[4maddftinfo[24m(1)                General Commands Manual               [4maddftinfo[24m(1)

[1mName[0m
       addftinfo - add font metrics to [4mtroff[24m fonts for use with [4mgroff[0m

[1mSynopsis[0m
       [1maddftinfo [22m[[1m-asc-height [4m[22mn[24m] [[1m-body-depth [4m[22mn[24m] [[1m-body-height [4m[22mn[24m]
                 [[1m-cap-height [4m[22mn[24m] [[1m-comma-depth [4m[22mn[24m] [[1m-desc-depth [4m[22mn[24m]
                 [[1m-fig-height [4m[22mn[24m] [[1m-x-height [4m[22mn[24m] [4mresolution[24m [4munit‐width[24m [4mfont[0m

       [1maddftinfo --help[0m

       [1maddftinfo -v[0m
       [1maddftinfo --version[0m

[1mDescription[0m
       [4maddftinfo[24m  reads  an  AT&T [4mtroff[24m font description file [4mfont[24m, adds addi‐
       tional font metric information required by GNU [4mtroff[24m(1), and writes the
       combined result to the standard output.  The information added  is  de‐
       rived  from the font’s existing parameters and assumptions about tradi‐
       tional [4mtroff[24m names for characters.  Among the font  metrics  added  are
       the  heights  and depths of characters (how far each extends vertically
       above and below the baseline).  The [4mresolution[24m and [4munit‐width[24m arguments
       should be the same as the corresponding parameters in  the  [4mDESC[24m  file.
       [4mfont[24m  is  the  name  of the file describing the font; if [4mfont[24m ends with
       “[1mI[22m”, the font is assumed to be oblique (or italic).

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       All other options change parameters that are used to derive the heights
       and depths.  Like the existing quantities in the font description file,
       each  value  [4mn[24m  is in [4mscaled[24m [4mpoints,[24m inches/[4mresolution[24m for a font whose
       type size is [4munit‐width[24m; see [4mgroff_font[24m(5).

       [1m-asc-height [4m[22mn[0m
              height of characters with ascenders, such as “b”, “d”, or “l”

       [1m-body-depth [4m[22mn[0m
              depth of characters such as parentheses

       [1m-body-height [4m[22mn[0m
              height of characters such as parentheses

       [1m-cap-height [4m[22mn[0m
              height of uppercase letters such as “A”

       [1m-comma-depth [4m[22mn[0m
              depth of a comma

       [1m-desc-depth [4m[22mn[0m
              depth of characters with descenders, such as “p”, “q”, or “y”

       [1m-fig-height[0m
              height of figures (numerals)

       [1m-x-height [4m[22mn[0m
              height of lowercase letters without ascenders such as “x”

       [4maddftinfo[24m makes no attempt to use the specified parameters to infer un‐
       specified parameters.  If a parameter is  not  specified,  the  default
       will be used.  The defaults are chosen to produce reasonable values for
       a Times font.

[1mSee also[0m
       [4mgroff_font[24m(5), [4mgroff[24m(1), [4mgroff_char[24m(7)

groff 1.23.0                      5 July 2023                     [4maddftinfo[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mafmtodit[24m(1)                 General Commands Manual                [4mafmtodit[24m(1)

[1mName[0m
       afmtodit  - adapt Adobe Font Metrics files for [4mgroff[24m PostScript and PDF
       output

[1mSynopsis[0m
       [1mafmtodit [22m[[1m-ckmnsx[22m] [[1m-a [4m[22mslant[24m] [[1m-d [4m[22mdevice‐description‐file[24m]
                [[1m-e [4m[22mencoding‐file[24m] [[1m-f [4m[22minternal‐name[24m] [[1m-i [4m[22mitalic‐correction‐[0m
                [4mfactor[24m] [[1m-o [4m[22moutput‐file[24m] [[1m-w [4m[22mspace‐width[24m] [4mafm‐file[24m [4mmap‐file[0m
                [4mfont‐description‐file[0m

       [1mafmtodit --help[0m

       [1mafmtodit -v[0m
       [1mafmtodit --version[0m

[1mDescription[0m
       [4mafmtodit[24m adapts an Adobe Font Metric file, [4mafm‐file[24m, for use  with  the
       [1mps [22mand [1mpdf [22moutput devices of [4mtroff[24m(1).  [4mmap‐file[24m associates a [4mgroff[24m or‐
       dinary  or special character name with a PostScript glyph name.  Output
       is written in [4mgroff_font[24m(5) format  to  [4mfont‐description‐file,[24m  a  file
       named for the intended [4mgroff[24m font name (but see the [1m-o [22moption).

       [4mmap‐file[24m should contain a sequence of lines of the form
              [4mps‐glyph[24m [4mgroff‐char[0m
       where  [4mps‐glyph[24m  is the PostScript glyph name and [4mgroff‐char[24m is a [4mgroff[0m
       ordinary (if of unit length) or special (if longer)  character  identi‐
       fier.   The  same  [4mps‐glyph[24m  can occur multiple times in the file; each
       [4mgroff‐char[24m must occur at most once.  Lines starting with “#” and  blank
       lines  are  ignored.  If the file isn’t found in the current directory,
       it is sought in the [4mdevps/generate[24m subdirectory of the default font di‐
       rectory.

       If a PostScript glyph is not mentioned in [4mmap‐file[24m, and a [4mgroff[24m charac‐
       ter name can’t be deduced using the Adobe Glyph List (AGL,  built  into
       [4mafmtodit[24m),  then [4mafmtodit[24m puts the PostScript glyph into the [4mgroff[24m font
       description file as an unnamed glyph which can only be accessed by  the
       “\N”  escape  sequence in a [4mroff[24m document.  In particular, this is true
       for glyph variants named in the form “[4mfoo[24m.[4mbar[24m”; all  glyph  names  con‐
       taining  one or more periods are mapped to unnamed entities.  Unless [1m-e[0m
       is specified, the encoding defined in the AFM file (i.e., entries  with
       non‐negative  codes)  is  used.   Refer  to  section “Using Symbols” in
       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, the [4mgroff[24m  Texinfo  manual,  or
       [4mgroff_char[24m(7),  which describe how [4mgroff[24m character identifiers are con‐
       structed.

       Glyphs not encoded in the AFM file (i.e., entries indexed as “-1”)  are
       still  available in [4mgroff[24m; they get glyph index values greater than 255
       (or greater than the biggest code used in the AFM file in the  unlikely
       case  that  it is greater than 255) in the [4mgroff[24m font description file.
       Unencoded glyph indices don’t have a specific order; it is best to  ac‐
       cess them only via special character identifiers.

       If the font file proper (not just its metrics) is available, listing it
       in  the  files  [4m/usr/share/groff/1.23.0/font/devps/download[24m  and  [4m/usr/[0m
       [4mshare/groff/1.23.0/font/devpdf/download[24m enables it to  be  embedded  in
       the output produced by [4mgrops[24m(1) and [4mgropdf[24m(1), respectively.

       If  the  [1m-i  [22moption is used, [4mafmtodit[24m automatically generates an italic
       correction, a left italic correction, and a  subscript  correction  for
       each  glyph  (the significance of these is explained in [4mgroff_font[24m(5));
       they can be specified for individual glyphs by adding to  the  [4mafm‐file[0m
       lines of the form:
              italicCorrection [4mps‐glyph[24m [4mn[0m
              leftItalicCorrection [4mps‐glyph[24m [4mn[0m
              subscriptCorrection [4mps‐glyph[24m [4mn[0m
       where [4mps‐glyph[24m is the PostScript glyph name, and [4mn[24m is the desired value
       of  the  corresponding parameter in thousandths of an em.  Such parame‐
       ters are normally needed only for italic (or oblique) fonts.

       The [1m-s [22moption should be given if the font is  “special”,  meaning  that
       [4mgroff[24m  should  search  it  whenever a glyph is not found in the current
       font.  In that case, [4mfont‐description‐file[24m should be listed as an argu‐
       ment to the [1mfonts [22mdirective in the output device’s [4mDESC[24m file; if it  is
       not  special,  there is no need to do so, since [4mtroff[24m(1) will automati‐
       cally mount it when it is first used.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-a [4m[22mslant[0m
              Use  [4mslant[24m as the slant (“angle”) parameter in the font descrip‐
              tion file; this is used by [4mgroff[24m in the positioning of  accents.
              By  default [4mafmtodit[24m uses the negative of the [1mItalicAngle [22mspeci‐
              fied in the AFM file; with true italic fonts it is sometimes de‐
              sirable to use a slant that is less than this.  If you find that
              an italic font places accents over base glyphs too  far  to  the
              right, use [1m-a [22mto give it a smaller slant.

       [1m-c     [22mInclude  comments  in  the font description file identifying the
              PostScript font.

       [1m-d [4m[22mdevice‐description‐file[0m
              The device description file is [4mdesc‐file[24m rather than the default
              [4mDESC[24m.  If not found in the current directory, the  [4mdevps[24m  subdi‐
              rectory  of the default font directory is searched (this is true
              for both the default device description file and  a  file  given
              with option [1m-d[22m).

       [1m-e [4m[22mencoding‐file[0m
              The  PostScript font should be reencoded to use the encoding de‐
              scribed in [4menc‐file[24m.  The format of  [4menc‐file[24m  is  described  in
              [4mgrops[24m(1).  If not found in the current directory, the [4mdevps[24m sub‐
              directory of the default font directory is searched.

       [1m-f [4m[22minternal‐name[0m
              The internal name of the [4mgroff[24m font is set to [4mname[24m.

       [1m-i [4m[22mitalic‐correction‐factor[0m
              Generate  an  italic correction for each glyph so that its width
              plus its italic correction is equal to  [4mitalic‐correction‐factor[0m
              thousandths  of an em plus the amount by which the right edge of
              the glyph’s bounding box is to the right of its origin.  If this
              would result in a negative italic correction, use a zero  italic
              correction instead.

              Also generate a subscript correction equal to the product of the
              tangent of the slant of the font and four fifths of the x‐height
              of  the  font.   If  this would result in a subscript correction
              greater than the italic correction, use a  subscript  correction
              equal to the italic correction instead.

              Also  generate  a left italic correction for each glyph equal to
              [4mitalic‐correction‐factor[24m thousandths of an em plus the amount by
              which the left edge of the glyph’s bounding box is to  the  left
              of  its  origin.  The left italic correction may be negative un‐
              less option [1m-m [22mis given.

              This option is normally needed only  with  italic  (or  oblique)
              fonts.   The  font description files distributed with [4mgroff[24m were
              created using an option of [1m-i50 [22mfor italic fonts.

       [1m-o [4m[22moutput‐file[0m
              Write to [4moutput‐file[24m instead of [4mfont‐description‐file.[0m

       [1m-k     [22mOmit any kerning data from the [4mgroff[24m font; use  only  for  mono‐
              spaced (constant‐width) fonts.

       [1m-m     [22mPrevent  negative  left italic correction values.  Font descrip‐
              tion files for roman styles distributed with [4mgroff[24m were  created
              with “[1m-i0 -m[22m” to improve spacing with [4meqn[24m(1).

       [1m-n     [22mDon’t  output  a [1mligatures [22mcommand for this font; use with mono‐
              spaced (constant‐width) fonts.

       [1m-s     [22mAdd the [1mspecial [22mdirective to the font description file.

       [1m-w [4m[22mspace‐width[0m
              Use [4mspace‐width[24m as the with of inter‐word spaces.

       [1m-x     [22mDon’t use the built‐in Adobe Glyph List.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devps/DESC[0m
              describes the [1mps [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devps/[24mF
              describes the font known as [4mF[24m on device [1mps[22m.

       [4m/usr/share/groff/1.23.0/font/devps/download[0m
              lists fonts available for embedding within the PostScript  docu‐
              ment (or download to the device).

       [4m/usr/share/groff/1.23.0/font/devps/generate/dingbats.map[0m
       [4m/usr/share/groff/1.23.0/font/devps/generate/dingbats-reversed.map[0m
       [4m/usr/share/groff/1.23.0/font/devps/generate/slanted-symbol.map[0m
       [4m/usr/share/groff/1.23.0/font/devps/generate/symbol.map[0m
       [4m/usr/share/groff/1.23.0/font/devps/generate/text.map[0m
              map  names  in  the  Adobe Glyph List to [4mgroff[24m special character
              identifiers for  Zapf  Dingbats  ([1mZD[22m),  reversed  Zapf  Dingbats
              ([1mZDR[22m),  slanted symbol ([1mSS[22m), symbol ([1mS[22m), and text fonts, respec‐
              tively.  These [4mmap‐file[24ms are used to produce the  font  descrip‐
              tion files provided with [4mgroff[24m for the [4mgrops[24m output driver.

[1mDiagnostics[0m
       AGL name '[4mx[24m' already mapped to groff name '[4my[24m'; ignoring AGL name
       'uni[4mXXXX[24m'
              You  can disregard these if they’re in the form shown, where the
              ignored AGL name contains four  hexadecimal  digits  [4mXXXX[24m.   The
              Adobe  Glyph  List  (AGL) has its own names for glyphs; they are
              often different from [4mgroff[24m’s special character names.   [4mafmtodit[0m
              is  constructing a mapping from [4mgroff[24m special character names to
              AGL names; this can be a one‐to‐one or many‐to‐one mapping,  but
              one‐to‐many  will not work, so [4mafmtodit[24m discards the excess map‐
              pings.  For example, if [4mx[24m is [1m*D[22m, [4my[24m is [1mDelta[22m, and [4mz[24m  is  [1muni0394[22m,
              [4mafmtodit[24m  is telling you that the [4mgroff[24m font description that it
              is writing cannot map the [4mgroff[24m special character [1m\[*D]  [22mto  AGL
              glyphs [1mDelta [22mand [1muni0394 [22mat the same time.

              If  you  get a message like this but are unhappy with which map‐
              ping is ignored, a remedy is to craft  an  alternative  [4mmap‐file[0m
              and re‐run [4mafmtodit[24m using it.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  Section “Using Symbols”  may  be
       of  particular  note.   You  can  browse  it  interactively  with “info
       '(groff)Using Symbols'”.

       [4mgroff[24m(1), [4mgropdf[24m(1), [4mgrops[24m(1), [4mgroff_font[24m(5)

groff 1.23.0                      5 July 2023                      [4mafmtodit[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mchem[24m(1)                     General Commands Manual                    [4mchem[24m(1)

[1mName[0m
       chem - embed chemical structure diagrams in [4mgroff[24m documents

[1mSynopsis[0m
       [1mchem [22m[[1m--[22m] [[4mfile[24m ...]

       [1mchem -h[0m
       [1mchem --help[0m

       [1mchem -v[0m
       [1mchem --version[0m

[1mDescription[0m
       [4mchem[24m produces chemical structure diagrams.   Today’s  version  is  best
       suited  for  organic  chemistry  (bonds, rings).  The [4mchem[24m program is a
       [4mgroff[24m preprocessor like [4meqn[24m, [4mpic[24m, [4mtbl[24m, etc.  It  generates  [4mpic[24m  output
       such  that  all [4mchem[24m parts are translated into diagrams of the [4mpic[24m lan‐
       guage.

       If no operands are given, or if [4mfile[24m is “[1m-[22m”, [4mchem[24m  reads  the  standard
       input  stream.   [1m-h  [22mand [1m--help [22mdisplay a usage message, whereas [1m-v [22mand
       [1m--version [22mdisplay version information; all exit.

       The program [4mchem[24m originates from the  Perl  source  file  [4mchem.pl[24m.   It
       tells  [4mpic[24m  to include a copy of the macro file [4mchem.pic[24m.  Moreover the
       [4mgroff[24m source file [4mpic.tmac[24m is loaded.

       In a style reminiscent of [4meqn[24m and [4mpic[24m, the [4mchem[24m diagrams are written in
       a special language.

       A set of [4mchem[24m lines looks like this

              .cstart
              [4mchem[24m [4mdata[0m
              .cend

       Lines containing the keywords [1m.cstart [22mand [1m.cend [22mstart and end the input
       for [4mchem[24m, respectively.  In [4mpic[24m context, i.e., after the call  of  [1m.PS[22m,
       [4mchem[24m  input  can optionally be started by the line [1mbegin chem [22mand ended
       by the line with the single word [1mend [22minstead.

       Anything outside these initialization lines is copied  through  without
       modification;  all  data  between the initialization lines is converted
       into [4mpic[24m commands to draw the diagram.

       As an example,

              .cstart
              CH3
              bond
              CH3
              .cend

       prints two [1mCH3 [22mgroups with a bond between them.

       If you want to create just [4mgroff[24m output, you must run [4mchem[24m followed  by
       [4mgroff[24m with the option [1m-p [22mfor the activation of [4mpic[24m:

              [4mchem[24m [[4mfile[24m ...] [1m| groff -p [22m...

[1mLanguage[0m
       The  [4mchem[24m input language is rather small.  It provides rings of several
       styles and a way to glue them together as  desired,  bonds  of  several
       styles, moieties (e.g., [1mC[22m, [1mNH3[22m, ..., and strings.

   [1mSetting variables[0m
       There  are  some  variables that can be set by commands.  Such commands
       have two possible forms, either

              [4mvariable[24m [4mvalue[0m

       or

              [4mvariable[24m [1m= [4m[22mvalue[0m

       This sets the given [4mvariable[24m to the argument [4mvalue[24m.  If more  arguments
       are  given only the last argument is taken, all other arguments are ig‐
       nored.

       There are only a few variables to be set by these commands:

       [1mtextht [4m[22marg[0m
              Set the height of the text to [4marg[24m; default is 0.16.

       [1mcwid [4m[22marg[0m
              Set the character width to [4marg[24m; default is 0.12.

       [1mdb [4m[22marg[24m Set the bond length to [4marg[24m; default is 0.2.

       [1msize [4m[22marg[0m
              Scale the diagram to make it look plausible at point  size  [4marg[24m;
              default is 10 point.

   [1mBonds[0m
       This

              [1mbond [22m[[4mdirection[24m] [[4mlength[24m [4mn[24m] [[1mfrom [4m[22mName[24m|[4mpicstuff[24m]

       draws a single bond in direction from nearest corner of [4mName[24m.  [1mbond [22mcan
       also  be [1mdouble bond[22m, [1mfront bond[22m, [1mback bond[22m, etc.  (We will get back to
       [4mName[24m soon.)

       [4mdirection[24m is the angle in degrees (0 up, positive clockwise) or  a  di‐
       rection  word like [1mup[22m, [1mdown[22m, [1msw [22m(= southwest), etc.  If no direction is
       specified, the bond goes in the current direction (usually that of  the
       last bond).

       Normally  the  bond  begins  at  the  last  object placed;  this can be
       changed by naming a [1mfrom [22mplace.  For instance, to make a  simple  alkyl
       chain:
              [1mCH3[0m
              [1mbond                [22m(this one goes right from the CH3)
              [1mC                   [22m(at the right end of the bond)
              [1mdouble bond up      [22m(from the C)
              [1mO                   [22m(at the end of the double bond)
              [1mbond right from C[0m
              [1mCH3[0m

       A  length  in  inches  may be specified to override the default length.
       Other [4mpic[24m commands can be tacked on to the end of a  bond  command,  to
       created dotted or dashed bonds or to specify a [1mto [22mplace.

   [1mRings[0m
       There  are  lots  of rings, but only five‐ and six‐sided rings get much
       support.  [1mring [22mby itself is a six‐sided ring; [1mbenzene  [22mis  the  benzene
       ring  with  a  circle  inside.  [1maromatic [22mputs a circle into any kind of
       ring.

              [1mring [22m[[1mpointing [22m([1mup[22m|[1mright[22m|[1mleft[22m|[1mdown[22m)] [[1maromatic[22m] [[1mput Mol at [4m[22mn[24m]
                   [[1mdouble [4m[22mi[24m,[4mj[24m [4mk[24m,[4ml[24m ... [[4mpicstuff[24m]

       The vertices of a ring are numbered 1, 2,  ...  from  the  vertex  that
       points  in the natural compass direction.  So for a hexagonal ring with
       the point at the top, the top vertex is 1, while  if  the  ring  has  a
       point at the east side, that is vertex 1.  This is expressed as

              R1: ring pointing up
              R2: ring pointing right

       The ring vertices are named [1m.V1[22m, ..., [1m.V[4m[22mn[24m, with [1m.V1 [22min the pointing di‐
       rection.  So the corners of [1mR1 [22mare [1mR1.V1 [22m(the [4mtop[24m), [1mR1.V2[22m, [1mR1.V3[22m, [1mR1.V4[0m
       (the  [4mbottom[24m),  etc., whereas for [1mR2[22m, [1mR2.V1 [22mis the rightmost vertex and
       [1mR2.V4 [22mthe leftmost.  These vertex names are used for  connecting  bonds
       or other rings.  For example,

              R1: benzene pointing right
              R2: benzene pointing right with .V6 at R1.V2

       creates two benzene rings connected along a side.

       Interior  double  bonds  are  specified as [1mdouble [4m[22mn1[24m[1m,[4m[22mn2[24m [4mn3[24m[1m,[4m[22mn4[24m ...[1m; [22meach
       number pair adds an interior bond.  So the alternate form of a  benzene
       ring is

              [1mring double 1,2 3,4 5,6[0m

       Heterocycles  (rings  with something other than carbon at a vertex) are
       written as [1mput [4m[22mX[24m [1mat [4m[22mV[24m, as in

              [1mR: ring put N at 1 put O at 2[0m

       In this heterocycle, [1mR.N [22mand [1mR.O [22mbecome synonyms for [1mR.V1 [22mand [1mR.V2[22m.

       There are two five‐sided rings.  [1mring5 [22mis pentagonal with a  side  that
       matches the six‐sided ring; it has four natural directions.  A [1mflatring[0m
       is a five‐sided ring created by chopping one corner of a six‐sided ring
       so that it exactly matches the six‐sided rings.

       The description of a ring has to fit on a single line.

   [1mMoieties and strings[0m
       A  moiety  is  a  string of characters beginning with a capital letter,
       such as N(C2H5)2.  Numbers are converted to subscripts (unless they ap‐
       pear to be fractional values, as in N2.5H).  The name of  a  moiety  is
       determined  from the moiety after special characters have been stripped
       out: e.g., N(C2H5)2) has the name NC2H52.

       Moieties can be specified in two kinds.  Normally a  moiety  is  placed
       right  after  the  last  thing mentioned, separated by a semicolon sur‐
       rounded by spaces, e.g.,

              [1mB1: bond ; OH[0m

       Here the moiety is [1mOH[22m; it is set after a bond.

       As the second kind a moiety can be positioned as the first  word  in  a
       [4mpic[24m‐like command, e.g.,

              [1mCH3 at C + (0.5,0.5)[0m

       Here  the  moiety  is [1mCH3[22m.  It is placed at a position relative to [1mC[22m, a
       moiety used earlier in the chemical structure.

       So moiety names can be specified as [4mchem[24m positions  everywhere  in  the
       [4mchem[24m code.  Beneath their printing moieties are names for places.

       The  moiety [1mBP [22mis special.  It is not printed but just serves as a mark
       to be referred to in later [4mchem[24m commands.  For example,

              [1mbond ; BP[0m

       sets a mark at the end of the bond.  This can be used then for specify‐
       ing a place.  The name [1mBP [22mis derived  from  [4mbranch[24m  [4mpoint[24m  (i.e.,  line
       crossing).

       A string within double quotes [1m" [22mis interpreted as a part of a [4mchem[24m com‐
       mand.   It  represents  a  string  that  should be printed (without the
       quotes).  Text within quotes [1m"[22m...[1m" [22mis treated more or less like a  moi‐
       ety except that no changes are made to the quoted part.

   [1mNames[0m
       In  the  alkyl chain above, notice that the carbon atom [1mC [22mwas used both
       to draw something and as the name for a place.  A moiety always defines
       a name for a place;  you can use your own names for places instead, and
       indeed, for rings you will have to.  A name is just

              [4mName[24m[1m: [22m...

       [4mName[24m is often the name of a moiety like [1mCH3[22m, but it  need  not  to  be.
       Any name that begins with a capital letter and which contains only let‐
       ters and numbers is valid:

              [1mFirst: bond[0m
                     [1mbond 30 from First[0m

   [1mMiscellaneous[0m
       The specific construction

              [1mbond [22m... [1m; moiety[0m

       is equivalent to

              bond
              moiety

       Otherwise,  each item has to be on a separate line (and only one line).
       Note that there must be whitespace after the semicolon which  separates
       the commands.

       A  period character [1m. [22mor a single quote [1m' [22min the first column of a line
       signals a [4mtroff[24m command, which is copied through as‐is.

       A line whose first non‐blank character  is  a  hash  character  ([1m#[22m)  is
       treated as a comment and thus ignored.  However, hash characters within
       a word are kept.

       A  line  whose first word is [1mpic [22mis copied through as‐is after the word
       [1mpic [22mhas been removed.

       The command

              [1msize [4m[22mn[0m

       scales the diagram to make it look plausible at point size  [4mn[24m  (default
       is 10 point).

       Anything else is assumed to be [4mpic[24m code, which is copied through with a
       label.

       Since  [4mchem[24m is a [4mpic[24m preprocessor, it is possible to include [4mpic[24m state‐
       ments in the middle of a diagram to draw things  not  provided  for  by
       [4mchem[24m  itself.   Such  [4mpic[24m statements should be included in [4mchem[24m code by
       adding [1mpic [22mas the first word of this line for clarity.

       The following [4mpic[24m commands are accepted as [4mchem[24m  commands,  so  no  [1mpic[0m
       command word is needed:

              [1mdefine [22mStart the definition of [4mpic[24m macro within [4mchem[24m.

              [1m[      [22mStart a block composite.

              [1m]      [22mEnd a block composite.

              [1m{      [22mStart a macro definition block.

              [1m}      [22mEnd a macro definition block.

       The macro names from [1mdefine [22mstatements are stored and their call is ac‐
       cepted as a [4mchem[24m command as well.

   [1mWish list[0m
       This TODO list was collected by Brian Kernighan.

       Error  checking is minimal; errors are usually detected and reported in
       an oblique fashion by [4mpic[24m.

       There is no library or file inclusion mechanism, and there is no short‐
       hand for repetitive structures.

       The extension mechanism is to create [4mpic[24m macros, but these  are  tricky
       to get right and don’t have all the properties of built‐in objects.

       There  is  no  in‐line chemistry yet (e.g., analogous to the [1m$[22m...[1m$ [22mcon‐
       struct of [4meqn[24m).

       There is no way to control entry point for bonds on groups.  Normally a
       bond connects to the carbon atom if entering from the top or bottom and
       otherwise to the nearest corner.

       Bonds from substituted atoms on heterocycles do not join at the  proper
       place without adding a bit of [4mpic[24m.

       There is no decent primitive for brackets.

       Text (quoted strings) doesn’t work very well.

       A squiggle bond is needed.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/pic/chem.pic[0m
              A collection of [4mpic[24m macros needed by [4mchem[24m.

       [4m/usr/share/groff/1.23.0/tmac/pic.tmac[0m
              A macro file which redefines [1m.PS[22m, [1m.PE[22m, and [1m.PF [22mto center [4mpic[24m di‐
              agrams.

       [4m/usr/share/doc/groff-1.23.0/examples/chem/[24m*[4m.chem[0m
              Example files for [4mchem[24m.

       [4m/usr/share/doc/groff-1.23.0/examples/chem/122/[24m*[4m.chem[0m
              Example files from the [4mchem[24m article by its authors, “CHEM—A Pro‐
              gram  for  Typesetting Chemical Structure Diagrams: User Manual”
              (CSTR #122).

[1mAuthors[0m
       The GNU version of  [4mchem[24m  was  written  by  Bernd  Warken  ⟨groff-bernd
       .warken-72@web.de⟩.    It  is  based  on  the  documentation  of  Brian
       Kernighan’s original [4mawk[24m version of [4mchem[24m.

[1mSee also[0m
       “CHEM—A Program for Typesetting Chemical Diagrams: User Manual” by  Jon
       L.  Bentley,  Lynn W. Jelinski, and Brian W. Kernighan, 1992, AT&T Bell
       Laboratories Computing Science Technical Report No. 122

       [4mgroff[24m(1), [4mpic[24m(1)

groff 1.23.0                      5 July 2023                          [4mchem[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4meqn[24m(1)                      General Commands Manual                     [4meqn[24m(1)

[1mName[0m
       eqn - format mathematics (equations) for [4mgroff[24m or MathML

[1mSynopsis[0m
       [1meqn [22m[[1m-CNrR[22m] [[1m-[22md [4mxy[24m] [[1m-f [4m[22mF[24m] [[1m-m [4m[22mn[24m] [[1m-M [4m[22mdir[24m] [[1m-p [4m[22mn[24m] [[1m-s [4m[22mn[24m] [[1m-T [4m[22mdev[24m]
           [[4mfile[24m ...]

       [1meqn --help[0m

       [1meqn -v[0m
       [1meqn --version[0m

[1mDescription[0m
       The GNU implementation of [4meqn[24m is part of the [4mgroff[24m(7) document  format‐
       ting  system.   [4meqn[24m  is a [4mtroff[24m(1) preprocessor that translates expres‐
       sions in its own language, embedded in [4mroff[24m(7) input files, into mathe‐
       matical notation typeset by [4mtroff[24m(1).  It copies each  [4mfile[24m’s  contents
       to  the standard output stream, translating each [4mequation[24m between lines
       starting with [1m.EQ [22mand [1m.EN[22m, or within a pair  of  user‐specified  delim‐
       iters.  Normally, [4meqn[24m is not executed directly by the user, but invoked
       by  specifying the [1m-e [22moption to [4mgroff[24m(1).  While GNU [4meqn[24m’s input syntax
       is highly compatible with AT&T [4meqn[24m, the output [4meqn[24m produces  cannot  be
       processed  by  AT&T  [4mtroff[24m; GNU [4mtroff[24m (or a [4mtroff[24m implementing relevant
       GNU extensions) must be used.  If no [4mfile[24m operands  are  given  on  the
       command line, or if [4mfile[24m is “[1m-[22m”, [4meqn[24m reads the standard input stream.

       Unless  the  [1m-R  [22moption is used, [4meqn[24m searches for the file [4meqnrc[24m in the
       directories given with the [1m-M [22moption first, then  in  [4m/usr/share/groff/[0m
       [4msite-tmac[24m,  and  finally  in  the  standard macro directory [4m/usr/share/[0m
       [4mgroff/1.23.0/tmac[24m.  If it exists and is readable, [4meqn[24m processes it  be‐
       fore any input files.

       This  man  page primarily discusses the differences between GNU [4meqn[24m and
       AT&T [4meqn[24m.  Most of the new features of the GNU [4meqn[24m input  language  are
       based on TeX.  There are some references to the differences between TeX
       and GNU [4meqn[24m below; these may safely be ignored if you do not know TeX.

       Three points are worth special note.

       • GNU  [4meqn[24m  emits  Presentation  MathML  output  when  invoked with the
         “[1m-T MathML[22m” option.

       • GNU [4meqn[24m does not support terminal devices well, though it may suffice
         for simple inputs.

       • GNU [4meqn[24m sets the input token “[1m...[22m” as an ellipsis on the  text  base‐
         line,  not  the  three centered dots of AT&T [4meqn[24m.  Set an ellipsis on
         the math axis with the GNU extension macro [1mcdots[22m.

   [1mAnatomy of an equation[0m
       [4meqn[24m input consists of tokens.  Consider a form of Newton’s  second  law
       of motion.  The input

              .EQ
              F =
              m a
              .EN

       becomes  [4mF[24m=[4mma[24m.  Each of [1mF[22m, [1m=[22m, [1mm[22m, and [1ma [22mis a token.  Spaces and newlines
       are interchangeable; they separate tokens but do  not  break  lines  or
       produce space in the output.

       The  following  input  characters  not only separate tokens, but manage
       their grouping and spacing as well.

       [1m{ }    [22mBraces perform grouping.  Whereas “[1me sup a b[22m” expresses  “([4me[24m  to
              the  [4ma[24m)  times [4mb[24m”, “[1me sup { a b }[22m” means “[4me[24m to the ([4ma[24m times [4mb[24m)”.
              When immediately preceded by a “[1mleft[22m” or  “[1mright[22m”  primitive,  a
              brace loses its special meaning.

       [1m^ ~    [22mare  the  [4mhalf[24m  [4mspace[24m and [4mfull[24m [4mspace,[24m respectively.  Use them to
              tune the appearance of the output.

       Tab and leader characters separate tokens  as  well  as  advancing  the
       drawing  position  to the next tab stop, but are seldom used in [4meqn[24m in‐
       put.  When they occur, they must appear at the outermost lexical scope.
       This roughly means that they can’t appear within braces that are neces‐
       sary to disambiguate the input; [4meqn[24m will  diagnose  an  error  in  this
       event.   (See subsection “Macros” below for additional token separation
       rules.)

       Other tokens are primitives, macros, an argument to either of the fore‐
       going, or components of an equation.

       [4mPrimitives[24m are fundamental keywords of the [4meqn[24m language.  They can con‐
       figure an aspect  of  the  preprocessor’s  state,  as  when  setting  a
       “global” font selection or type size ([1mgfont [22mand [1mgsize[22m), or declaring or
       deleting macros (“[1mdefine[22m” and [1mundef[22m); these are termed [4mcommands.[24m  Other
       primitives  perform  formatting operations on the tokens after them (as
       with [1mfat[22m, [1mover[22m, [1msqrt[22m, or [1mup[22m).

       Equation [4mcomponents[24m include mathematical variables, constants,  numeric
       literals,  and operators.  [4meqn[24m remaps some input character sequences to
       [4mgroff[24m special character escape sequences for economy in equation  entry
       and  to  ensure  that  glyphs  from  an  unstyled  font  are  used; see
       [4mgroff_char[24m(7).

              +   \[pl]                '    \[fm]
              ‐   \[mi]                <=   \[<=]
              =   \[eq]                >=   \[>=]

       [4mMacros[24m permit primitives, components, and other macros to be  collected
       and  referred  to by a single token.  Predefined macros make convenient
       the preparation of [4meqn[24m input in a form resembling  its  spoken  expres‐
       sion; for example, consider [1mcos[22m, [1mhat[22m, [1minf[22m, and [1mlim[22m.

   [1mSpacing and typeface[0m
       GNU  [4meqn[24m  imputes types to the components of an equation, adjusting the
       spacing between them accordingly.  Recognized  types  are  as  follows;
       most  affect  spacing  only, whereas the “[1mletter[22m” subtype of “[1mordinary[22m”
       also assigns a style.

         ordinary      character such as “1”, “a”, or “!”
           letter      character to be italicized by default
           digit       [4mn/a[0m
         operator      large operator such as “Σ”
         binary        binary operator such as “+”
         relation      relational operator such as “=”
         opening       opening bracket such as “(”
         closing       closing bracket such as “)”
         punctuation   punctuation character such as “,”
         inner         sub‐formula contained within brackets
         suppress      component to which automatic spacing is not applied

       Two primitives apply types to equation components.

       [1mtype [4m[22mt[24m [4me[0m
              Apply type [4mt[24m to expression [4me[24m.

       [1mchartype [4m[22mt[24m [4mtext[0m
              Assign each character in (unquoted) [4mtext[24m type [4mt[24m, persistently.

       [4meqn[24m sets up spacings and styles as if by the following commands.

              chartype "letter"      abcdefghiklmnopqrstuvwxyz
              chartype "letter"      ABCDEFGHIKLMNOPQRSTUVWXYZ
              chartype "letter"      \[*a]\[*b]\[*g]\[*d]\[*e]\[*z]
              chartype "letter"      \[*y]\[*h]\[*i]\[*k]\[*l]\[*m]
              chartype "letter"      \[*n]\[*c]\[*o]\[*p]\[*r]\[*s]
              chartype "letter"      \[*t]\[*u]\[*f]\[*x]\[*q]\[*w]
              chartype "binary"      *\[pl]\[mi]
              chartype "relation"    <>\[eq]\[<=]\[>=]
              chartype "opening"     {([
              chartype "closing"     })]
              chartype "punctuation" ,;:.
              chartype "suppress"    ^~

       [4meqn[24m assigns all other ordinary and special [4mroff[24m  characters,  including
       numerals  0–9, the “[1mordinary[22m” type.  (The “[1mdigit[22m” type is not used, but
       is available for customization.)  In keeping with  common  practice  in
       mathematical  typesetting,  lowercase, but not uppercase, Greek letters
       are assigned the “[1mletter[22m” type to style them in  italics.   The  macros
       for producing ellipses, “[1m...[22m”, [1mcdots[22m, and [1mldots[22m, use the “[1minner[22m” type.

   [1mPrimitives[0m
       [4meqn[24m  supports  without  alteration the AT&T [4meqn[24m primitives [1mabove[22m, [1mback[22m,
       [1mbar[22m, [1mbold[22m, [1mdefine[22m, [1mdown[22m, [1mfat[22m, [1mfont[22m, [1mfrom[22m, [1mfwd[22m,  [1mgfont[22m,  [1mgsize[22m,  [1mitalic[22m,
       [1mleft[22m,  [1mlineup[22m,  [1mmark[22m,  [1mmatrix[22m, [1mndefine[22m, [1mover[22m, [1mright[22m, [1mroman[22m, [1msize[22m, [1msqrt[22m,
       [1msub[22m, [1msup[22m, [1mtdefine[22m, [1mto[22m, [1munder[22m, and [1mup[22m.

   [1mNew primitives[0m
       The GNU extension primitives “[1mtype[22m” and [1mchartype [22mare discussed in  sub‐
       section  “Spacing  and typeface” above; “[1mset[22m” in subsection “Customiza‐
       tion” below; and [1mgrfont [22mand [1mgbfont [22min subsection “Fonts” below.  In the
       following synopses, [4mX[24m can be any character not appearing in the parame‐
       ter thus bracketed.

       [4me1[24m [1maccent [4m[22me2[0m
              Set [4me2[24m as an accent over [4me1[24m.  [4me2[24m is assumed to be at the  appro‐
              priate  height  for a lowercase letter without an ascender;  [4meqn[0m
              vertically shifts it depending on [4me1[24m’s height.  For example, [1mhat[0m
              is defined as follows.

                     accent { "^" }

              [1mdotdot[22m, [1mdot[22m, [1mtilde[22m, [1mvec[22m, and [1mdyad [22mare  also  defined  using  the
              [1maccent [22mprimitive.

       [1mbig [4m[22me[24m  Enlarge  the  expression  [4me[24m; semantics like those of CSS “large”
              are intended.  In [4mtroff[24m output, the type size is increased by  5
              scaled points.  MathML output emits the following.

                     <mstyle mathsize='big'>

       [1mcopy [4m[22mfile[0m
       [1minclude [4m[22mfile[0m
              Interpolate  the contents of [4mfile[24m, omitting lines beginning with
              [1m.EQ [22mor [1m.EN[22m.  If a relative path name, [4mfile[24m is sought relative to
              the current working directory.

       [1mifdef [4m[22mname[24m [4mX[24m [4manything[24m [4mX[0m
              If [4mname[24m is defined as a primitive or macro, interpret [4manything[24m.

       [1mnosplit [4m[22mtext[0m
              As "[4mtext[24m", but since [4mtext[24m is not quoted it is subject  to  macro
              expansion; it is not split up and the spacing between characters
              not adjusted per subsection “Spacing and typeface” above.

       [4me[24m [1mopprime[0m
              As  [1mprime[22m, but set the prime symbol as an operator on [4me[24m.  In the
              input “[1mA opprime sub 1[22m”, the “1” is tucked under the prime as  a
              subscript  to  the “A” (as is conventional in mathematical type‐
              setting), whereas when [1mprime [22mis used, the “1” is a subscript  to
              the  prime  character.  The precedence of [1mopprime [22mis the same as
              that of [1mbar [22mand “[1munder[22m”, and higher than that  of  other  primi‐
              tives  except  [1maccent  [22mand [1muaccent[22m.  In unquoted text, a neutral
              apostrophe ([1m'[22m) that is not the first character on the input line
              is treated like [1mopprime[22m.

       [1msdefine [4m[22mname[24m [4mX[24m [4manything[24m [4mX[0m
              As “[1mdefine[22m”, but [4mname[24m is not recognized as  a  macro  if  called
              with arguments.

       [4me1[24m [1msmallover [4m[22me2[0m
              As  [1mover[22m,  but reduces the type size of [4me1[24m and [4me2[24m, and puts less
              vertical space between [4me1[24m and [4me2[24m and the fraction bar.  The [1mover[0m
              primitive corresponds to the TeX [1m\over  [22mprimitive  in  displayed
              equation  styles;  [1msmallover [22mcorresponds to [1m\over [22min non‐display
              (“inline”) styles.

       [1mspace [4m[22mn[0m
              Set extra vertical spacing around the  equation,  replacing  the
              default  values,  where  [4mn[24m is an integer in hundredths of an em.
              If positive, [4mn[24m increases vertical spacing before  the  equation;
              if negative, it does so after the equation.  This primitive pro‐
              vides  an  interface to [4mgroff[24m’s [1m\x [22mescape sequence, but with the
              opposite sign convention.  It has no effect if the  equation  is
              part of a [4mpic[24m(1) picture.

       [1mspecial [4m[22mtroff‐macro[24m [4me[0m
              Construct  an  object  by  calling  [4mtroff‐macro[24m on [4me[24m.  The [4mtroff[0m
              string [1m0s [22mcontains the [4meqn[24m output for [4me[24m, and the  registers  [1m0w[22m,
              [1m0h[22m,  [1m0d[22m,  [1m0skern[22m,  and [1m0skew [22mthe width, height, depth, subscript
              kern, and skew of [4me[24m, respectively.  (The [4msubscript[24m  [4mkern[24m  of  an
              object  indicates  how much a subscript on that object should be
              “tucked in”, or placed to the left relative to a non‐subscripted
              glyph of the same size.  The [4mskew[24m of an object is how far to the
              right of the center of the object an accent over  it  should  be
              placed.)   The  macro  must modify [1m0s [22mso that it outputs the de‐
              sired result, returns the drawing position to the text  baseline
              at  the  beginning  of [4me[24m, and updates the foregoing registers to
              correspond to the new dimensions of the result.

              Suppose you want a construct that  “cancels”  an  expression  by
              drawing a diagonal line through it.

                     .de Ca
                     .  ds 0s \
                     \Z'\\*(0s'\
                     \v'\\n(0du'\
                     \D'l \\n(0wu -\\n(0hu-\\n(0du'\
                     \v'\\n(0hu'
                     ..
                     .EQ
                     special Ca "x \[mi] 3 \[pl] x" ~ 3
                     .EN

              We use the [1m\[mi] [22mand [1m\[pl] [22mspecial characters instead of + and -
              because  they  are part of the argument to a [4mtroff[24m macro, so [4meqn[0m
              does not transform them to mathematical glyphs for us.  Here’s a
              more complicated construct that draws a box  around  an  expres‐
              sion;  the bottom of the box rests on the text baseline.  We de‐
              fine the [4meqn[24m macro [1mbox [22mto wrap the call of the [4mtroff[24m macro [1mBx[22m.

                     .de Bx
                     .ds 0s \
                     \Z'\\h'1n'\\*[0s]'\
                     \v'\\n(0du+1n'\
                     \D'l \\n(0wu+2n 0'\
                     \D'l 0 -\\n(0hu-\\n(0du-2n'\
                     \D'l -\\n(0wu-2n 0'\
                     \D'l 0 \\n(0hu+\\n(0du+2n'\
                     \h'\\n(0wu+2n'
                     .nr 0w +2n
                     .nr 0d +1n
                     .nr 0h +1n
                     ..
                     .EQ
                     define box ' special Bx $1 '
                     box(foo) ~ "bar"
                     .EN

       [1msplit "[4m[22mtext[24m[1m"[0m
              As [4mtext[24m, but since [4mtext[24m is quoted, it is not  subject  to  macro
              expansion; it is split up and the spacing between characters ad‐
              justed per subsection “Spacing and typeface” above.

       [4me1[24m [1muaccent [4m[22me2[0m
              Set [4me2[24m as an accent under [4me1[24m.  [4me2[24m is assumed to be at the appro‐
              priate  height for a letter without a descender;  [4meqn[24m vertically
              shifts it depending on whether [4me1[24m has a  descender.   [1mutilde  [22mis
              predefined using [1muaccent [22mas a tilde accent below the baseline.

       [1mundef [4m[22mname[0m
              Remove  definition  of  macro or primitive [4mname[24m, making it unde‐
              fined.

       [1mvcenter [4m[22me[0m
              Vertically center [4me[24m about the [4mmath[24m [4maxis[24m, a horizontal line  upon
              which  fraction  bars  and  characters  such  as “+” and “−” are
              aligned.  MathML already behaves this way, so [4meqn[24m  ignores  this
              primitive  when  producing that output format.  The built‐in [1msum[0m
              macro is defined as if by the following.

                     define sum ! { type "operator" vcenter size +5 \(*S } !

   [1mExtended primitives[0m
       GNU [4meqn[24m extends the syntax of some AT&T [4meqn[24m primitives, introducing one
       deliberate incompatibility.

       [1mdelim on[0m
              [4meqn[24m recognizes an “[1mon[22m” argument  to  the  [1mdelim  [22mprimitive  spe‐
              cially, restoring any delimiters previously disabled with “[1mdelim[0m
              [1moff[22m”.  If delimiters haven’t been specified, neither command has
              effect.   Few  [4meqn[24m  documents are expected to use “o” and “n” as
              left and right delimiters, respectively.  If  yours  does,  con‐
              sider swapping them, or select others.

       [1mcol [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mccol [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mlcol [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mrcol [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mpile [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mcpile [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mlpile [4m[22mn[24m [1m{ [22m... [1m}[0m
       [1mrpile [4m[22mn[24m [1m{ [22m... [1m}[0m
              The  integer value [4mn[24m (in hundredths of an em) increases the ver‐
              tical spacing between rows, using  [4mgroff[24m’s  [1m\x  [22mescape  sequence
              (the  value  has no effect in MathML mode).  Negative values are
              accepted but have no effect.  If more than one [4mn[24m occurs in a ma‐
              trix or pile, the largest is used.

   [1mCustomization[0m
       When [4meqn[24m generates [4mtroff[24m input, the appearance  of  equations  is  con‐
       trolled by a large number of parameters.  They have no effect when gen‐
       erating  MathML,  which delegates typesetting to a MathML rendering en‐
       gine.  Configure these parameters with the [1mset [22mprimitive.

       [1mset [4m[22mp[24m [4mn[0m
              assigns parameter [4mp[24m the integer value [4mn[24m;  [4mn[24m  is  interpreted  in
              units of hundredths of an em unless otherwise stated.  For exam‐
              ple,

                     set x_height 45

              says  that  [4meqn[24m  should  assume  that  the  font’s  x‐height  is
              0.45 ems.

              Available parameters are  as  follows;  defaults  are  shown  in
              parentheses.   We  intend  these  descriptions  to be expository
              rather than rigorous.

              [1mminimum_size     [22msets a floor  for  the  type  size  (in  scaled
                               points) at which equations are set ([1m5[22m).

              [1mfat_offset       [22mThe  [1mfat  [22mprimitive  emboldens  an  equation by
                               overprinting two copies of the  equation  hori‐
                               zontally  offset by this amount ([1m4[22m).  In MathML
                               mode, components to  which  [1mfat_offset  [22mapplies
                               instead use the following.
                                      <mstyle mathvariant='double-struck'>

              [1mover_hang        [22mA  fraction  bar is longer by twice this amount
                               than the maximum of the widths of the numerator
                               and denominator; in other words,  it  overhangs
                               the  numerator and denominator by at least this
                               amount ([1m0[22m).

              [1maccent_width     [22mWhen [1mbar [22mor [1munder [22mis applied to a single  char‐
                               acter,  the  line is this long ([1m31[22m).  Normally,
                               [1mbar [22mor [1munder [22mproduces a line  whose  length  is
                               the width of the object to which it applies; in
                               the  case  of a single character, this tends to
                               produce a line that looks too long.

              [1mdelimiter_factor [22mExtensible delimiters produced  with  the  [1mleft[0m
                               and [1mright [22mprimitives have a combined height and
                               depth  of  at  least  this  many thousandths of
                               twice the maximum amount by which the sub‐equa‐
                               tion that the delimiters enclose  extends  away
                               from the axis ([1m900[22m).

              [1mdelimiter_shortfall[0m
                               Extensible  delimiters  produced  with the [1mleft[0m
                               and [1mright [22mprimitives have a combined height and
                               depth not less than the difference of twice the
                               maximum amount by which the  sub‐equation  that
                               the  delimiters  enclose  extends away from the
                               axis and this amount ([1m50[22m).

              [1mnull_delimiter_space[0m
                               This much horizontal space is inserted on  each
                               side of a fraction ([1m12[22m).

              [1mscript_space     [22mThe width of subscripts and superscripts is in‐
                               creased by this amount ([1m5[22m).

              [1mthin_space       [22mThis  amount of space is automatically inserted
                               after punctuation characters.  It also  config‐
                               ures  the  width of the space produced by the [1m^[0m
                               token ([1m17[22m).

              [1mmedium_space     [22mThis amount of space is automatically  inserted
                               on either side of binary operators ([1m22[22m).

              [1mthick_space      [22mThis  amount of space is automatically inserted
                               on either side of relations.  It  also  config‐
                               ures  the  width of the space produced by the [1m~[0m
                               token ([1m28[22m).

              [1mx_height         [22mThe height of lowercase letters without  ascen‐
                               ders such as “x” ([1m45[22m).

              [1maxis_height      [22mThe  height above the baseline of the center of
                               characters such as “+” and “−” ([1m26[22m).  It is im‐
                               portant that this value is correct for the font
                               you are using.

              [1mdefault_rule_thickness[0m
                               This should be set  to  the  thickness  of  the
                               [1m\[ru] [22mcharacter, or the thickness of horizontal
                               lines produced with the [1m\D [22mescape sequence ([1m4[22m).

              [1mnum1             [22mThe  [1mover  [22mprimitive shifts up the numerator by
                               at least this amount ([1m70[22m).

              [1mnum2             [22mThe [1msmallover [22mprimitive shifts up the numerator
                               by at least this amount ([1m36[22m).

              [1mdenom1           [22mThe [1mover [22mprimitive shifts down the  denominator
                               by at least this amount ([1m70[22m).

              [1mdenom2           [22mThe [1msmallover [22mprimitive shifts down the denomi‐
                               nator by at least this amount ([1m36[22m).

              [1msup1             [22mNormally  superscripts  are  shifted  up  by at
                               least this amount ([1m42[22m).

              [1msup2             [22mSuperscripts within superscripts or upper  lim‐
                               its  or  numerators  of [1msmallover [22mfractions are
                               shifted up by at least this amount ([1m37[22m).   Con‐
                               ventionally, this is less than [1msup1[22m.

              [1msup3             [22mSuperscripts   within  denominators  or  square
                               roots or subscripts or lower limits are shifted
                               up by at least this amount  ([1m28[22m).   Convention‐
                               ally, this is less than [1msup2[22m.

              [1msub1             [22mSubscripts  are  normally  shifted  down  by at
                               least this amount ([1m20[22m).

              [1msub2             [22mWhen there is both a  subscript  and  a  super‐
                               script,  the  subscript  is  shifted down by at
                               least this amount ([1m23[22m).

              [1msup_drop         [22mThe baseline of a superscript is no  more  than
                               this  much below the top of the object on which
                               the superscript is set ([1m38[22m).

              [1msub_drop         [22mThe baseline of a subscript is  at  least  this
                               much  below  the  bottom of the object on which
                               the subscript is set ([1m5[22m).

              [1mbig_op_spacing1  [22mThe baseline of an upper limit is at least this
                               much above the top of the object on  which  the
                               limit is set ([1m11[22m).

              [1mbig_op_spacing2  [22mThe  baseline of a lower limit is at least this
                               much below the bottom of the  object  on  which
                               the limit is set ([1m17[22m).

              [1mbig_op_spacing3  [22mThe  bottom  of an upper limit is at least this
                               much above the top of the object on  which  the
                               limit is set ([1m20[22m).

              [1mbig_op_spacing4  [22mThe  top of a lower limit is at least this much
                               below the bottom of the  object  on  which  the
                               limit is set ([1m60[22m).

              [1mbig_op_spacing5  [22mThis much vertical space is added above and be‐
                               low limits ([1m10[22m).

              [1mbaseline_sep     [22mThe  baselines  of the rows in a pile or matrix
                               are normally this  far  apart  ([1m140[22m).   Usually
                               equal to the sum of [1mnum1 [22mand [1mdenom1[22m.

              [1mshift_down       [22mThe  midpoint  between the top baseline and the
                               bottom baseline in a matrix or pile is  shifted
                               down  by this much from the axis ([1m26[22m).  Usually
                               equal to [1maxis_height[22m.

              [1mcolumn_sep       [22mThis much space is added between columns  in  a
                               matrix ([1m100[22m).

              [1mmatrix_side_sep  [22mThis  much space is added at each side of a ma‐
                               trix ([1m17[22m).

              [1mdraw_lines       [22mIf non‐zero, [4meqn[24m draws lines using the [4mtroff[24m [1m\D[0m
                               escape sequence, rather than the [1m\l [22mescape  se‐
                               quence  and  the  [1m\[ru] [22mspecial character.  The
                               [4meqnrc[24m file sets the default: [1m1 [22mon [1mps[22m, [1mhtml[22m, and
                               the X11 devices, otherwise [1m0[22m.

              [1mbody_height      [22mis the presumed height of an equation above the
                               text baseline; [4meqn[24m adds  any  excess  as  extra
                               pre‐vertical  line  spacing with [4mtroff[24m’s [1m\x [22mes‐
                               cape sequence ([1m85[22m).

              [1mbody_depth       [22mis the presumed depth of an equation below  the
                               text  baseline;  [4meqn[24m  adds  any excess as extra
                               post‐vertical line spacing with [4mtroff[24m’s [1m\x  [22mes‐
                               cape sequence ([1m35[22m).

              [1mnroff            [22mIf  non‐zero,  then [1mndefine [22mbehaves like [1mdefine[0m
                               and [1mtdefine [22mis ignored, otherwise  [1mtdefine  [22mbe‐
                               haves  like [1mdefine [22mand [1mndefine [22mis ignored.  The
                               [4meqnrc[24m  file  sets  the  default:  [1m1  [22mon  [1mascii[22m,
                               [1mlatin1[22m, [1mutf8[22m, and [1mcp1047 [22mdevices, otherwise [1m0[22m.

   [1mMacros[0m
       In  GNU  [4meqn[24m,  macros can take arguments.  A word defined by any of the
       [1mdefine[22m, [1mndefine[22m, or [1mtdefine [22mprimitives followed immediately by  a  left
       parenthesis is treated as a [4mparameterized[24m [4mmacro[24m [4mcall:[24m subsequent tokens
       up to a matching right parenthesis are treated as comma‐separated argu‐
       ments.   In this context only, commas and parentheses also serve as to‐
       ken separators.  A macro argument is not terminated by a  comma  inside
       parentheses  nested  within  it.  In a macro definition, [1m$[4m[22mn[24m, where [4mn[24m is
       between 1 and 9 inclusive, is replaced by the [4mn[24mth  argument;  if  there
       are fewer than [4mn[24m arguments, it is replaced by nothing.

   [1mPredefined macros[0m
       GNU  [4meqn[24m  supports  the  predefined  macros  offered  by AT&T [4meqn[24m: [1mand[22m,
       [1mapprox[22m, [1marc[22m, [1mcos[22m, [1mcosh[22m, [1mdel[22m, [1mdet[22m, [1mdot[22m, [1mdotdot[22m, [1mdyad[22m,  [1mexp[22m,  [1mfor[22m,  [1mgrad[22m,
       [1mhalf[22m,  [1mhat[22m,  [1mif[22m,  [1minter[22m, [1mIm[22m, [1minf[22m, [1mint[22m, [1mlim[22m, [1mln[22m, [1mlog[22m, [1mmax[22m, [1mmin[22m, [1mnothing[22m,
       [1mpartial[22m, [1mprime[22m, [1mprod[22m, [1mRe[22m, [1msin[22m, [1msinh[22m,  [1msum[22m,  [1mtan[22m,  [1mtanh[22m,  [1mtilde[22m,  [1mtimes[22m,
       [1munion[22m, [1mvec[22m, [1m==[22m, [1m!=[22m, [1m+=[22m, [1m->[22m, [1m<-[22m, [1m<<[22m, [1m>>[22m, and “[1m...[22m”.  The lowercase clas‐
       sical  Greek letters are available as [1malpha[22m, [1mbeta[22m, [1mchi[22m, [1mdelta[22m, [1mepsilon[22m,
       [1meta[22m, [1mgamma[22m, [1miota[22m, [1mkappa[22m, [1mlambda[22m, [1mmu[22m, [1mnu[22m, [1momega[22m, [1momicron[22m, [1mphi[22m, [1mpi[22m,  [1mpsi[22m,
       [1mrho[22m, [1msigma[22m, [1mtau[22m, [1mtheta[22m, [1mupsilon[22m, [1mxi[22m, and [1mzeta[22m.  Spell them with an ini‐
       tial  capital  letter ([1mAlpha[22m) or in full capitals ([1mALPHA[22m) to obtain up‐
       percase forms.

       GNU [4meqn[24m further defines the macros [1mcdot[22m, [1mcdots[22m, and  [1mutilde  [22m(all  dis‐
       cussed  above), [1mdollar[22m, which sets a dollar sign, and [1mldots[22m, which sets
       an ellipsis on the text baseline.

   [1mFonts[0m
       [4meqn[24m uses up to three typefaces to set an  equation:  italic  (oblique),
       roman (upright), and bold.  Assign each a [4mgroff[24m typeface with the prim‐
       itives  [1mgfont[22m,  [1mgrfont[22m,  and [1mgbfont.  [22mThe defaults are the styles [1mI[22m, [1mR[22m,
       and [1mB [22m(applied to the current font  family).   The  [1mchartype  [22mprimitive
       (see  above) sets a character’s type, which determines the face used to
       set it.  The “[1mletter[22m” type is set in italics; others are set in  roman.
       Use the [1mbold [22mprimitive to select an (upright) bold style.

       [1mgbfont [4m[22mf[0m
              Select [4mf[24m as the bold font.  This is a GNU extension.

       [1mgfont [4m[22mf[0m
              Select [4mf[24m as the italic font.

       [1mgrfont [4m[22mf[0m
              Select [4mf[24m as the roman font.  This is a GNU extension.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-C     [22mRecognize [1m.EQ [22mand [1m.EN [22meven when followed by  a  character  other
              than space or newline.

       [1m-d [4m[22mxy[24m  Specify  delimiters [4mx[24m for left and [4my[24m for right ends of equations
              not bracketed by [1m.EQ[22m/[1m.EN[22m.  [4mx[24m and [4my[24m need not  be  distinct.   Any
              “[1mdelim [4m[22mxy[24m” statements in the source file override this option.

       [1m-f [4m[22mF[24m   is equivalent to “[1mgfont [4m[22mF[24m”.

       [1m-m [4m[22mn[24m   is equivalent to “[1mset minimum_size [4m[22mn[24m”.

       [1m-M [4m[22mdir[24m Search  [4mdir[24m  for  [4meqnrc[24m before those listed in section “Descrip‐
              tion” above.

       [1m-N     [22mProhibit newlines within delimiters.  This option allows [4meqn[24m  to
              recover better from missing closing delimiters.

       [1m-p [4m[22mn[24m   Set  sub‐ and superscripts [4mn[24m points smaller than the surrounding
              text.  This option is deprecated.  [4meqn[24m normally  sets  sub‐  and
              superscripts at 70% of the type size of the surrounding text.

       [1m-r     [22mReduce  the type size of subscripts at most once relative to the
              base type size for the equation.

       [1m-R     [22mDon’t load [4meqnrc[24m.

       [1m-s [4m[22mn[24m   is equivalent to “[1mgsize [4m[22mn[24m”.  This option is deprecated.

       [1m-T [4m[22mdev[24m Prepare output for the device [4mdev[24m.  In most cases, the effect of
              this is to define a macro [4mdev[24m with a value of [1m1[22m; [4meqnrc[24m uses this
              to provide definitions appropriate for the device.  However,  if
              the  specified  driver  is “MathML”, the output is MathML markup
              rather than [4mtroff[24m input, and [4meqnrc[24m is not loaded  at  all.   The
              default output device is [1mps[22m.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/eqnrc[0m
              Initialization file.

[1mMathML mode limitations[0m
       MathML  is  designed  on  the  assumption that it cannot know the exact
       physical characteristics of the media and devices on which it  will  be
       rendered.  It does not support control of motions and sizes to the same
       degree [4mtroff[24m does.

       • [4meqn[24m customization parameters have no effect on generated MathML.

       • The  [1mspecial[22m,  [1mup[22m,  [1mdown[22m,  [1mfwd[22m,  and [1mback [22mprimitives cannot be imple‐
         mented, and yield a MathML “<merror>” message instead.

       • The [1mvcenter [22mprimitive is silently ignored, as centering on  the  math
         axis is the MathML default.

       • Characters  that [4meqn[24m sets extra large in [4mtroff[24m mode—notably the inte‐
         gral sign—may appear too small and  need  to  have  their  “<mstyle>”
         wrappers adjusted by hand.

       As  in its [4mtroff[24m mode, [4meqn[24m in MathML mode leaves the [1m.EQ [22mand [1m.EN [22mtokens
       in place, but emits nothing corresponding to  [1mdelim  [22mdelimiters.   They
       can,  however,  be  recognized  as  character sequences that begin with
       “<math>”, end with “</math>”, and do not cross line boundaries.

[1mCaveats[0m
       Tokens must be double‐quoted in [4meqn[24m input if they are not to be  recog‐
       nized  as  names  of  macros or primitives, or if they are to be inter‐
       preted by [4mtroff[24m.  In particular, short ones, like “[1mpi[22m”  and  “[1mPI[22m”,  can
       collide  with  [4mtroff[24m identifiers.  For instance, the [4meqn[24m command “[1mgfont[0m
       [1mPI[22m” does not select [4mgroff[24m’s Palatino italic font for the global  italic
       face; you must use “[1mgfont "PI"[22m” instead.

       Delimited  equations  are set at the type size current at the beginning
       of the input line, not necessarily that immediately preceding the open‐
       ing delimiter.

       Unlike TeX, [4meqn[24m does not inherently distinguish  displayed  and  inline
       equation  styles;  see  the  [1msmallover [22mprimitive above.  However, macro
       packages frequently define [1mEQ [22mand [1mEN  [22mmacros  such  that  the  equation
       within  is displayed.  These macros may accept arguments permitting the
       equation to be labeled or captioned; see the package’s documentation.

[1mBugs[0m
       [4meqn[24m abuses terminology—its “equations” can be  inequalities,  bare  ex‐
       pressions,  or  unintelligible  gibberish.   But there’s no changing it
       now.

       In [4mnroff[24m mode, lowercase Greek letters are rendered in roman instead of
       italic style.

       In MathML mode, the [1mmark [22mand [1mlineup [22mfeatures don’t work.  These  could,
       in theory, be implemented with “<maligngroup>” elements.

       In  MathML  mode, each digit of a numeric literal gets a separate “<mn>
       </mn>” pair, and decimal points are tagged with “<mo></mo>”.   This  is
       allowed by the specification, but inefficient.

[1mExamples[0m
       We first illustrate [4meqn[24m usage with a trigonometric identity.

              .EQ
              sin ( alpha + beta ) = sin alpha cos beta + cos alpha sin beta
              .EN

       It  can be convenient to set up delimiters if mathematical content will
       appear frequently in running text.

              .EQ
              delim $$
              .EN
              Having cached a table of logarithms,
              the property $ln ( x y ) = ln x + ln y$ sped calculations.

       The quadratic formula illustrates use of fractions  and  radicals,  and
       affords an opportunity to use the full space token [1m~[22m.

              .EQ
              x = { - b ~ \[+-] ~ sqrt { b sup 2 - 4 a c } } over { 2 a }
              .EN

       Alternatively,  we  could define the plus‐minus sign as a binary opera‐
       tor.  Automatic spacing puts 0.06 em less space on either side  of  the
       plus‐minus than ~ does, this being the difference between the widths of
       the  [1mmedium_space  [22mparameter  used  by binary operators and that of the
       full space.  Independently, we can define a macro  “frac”  for  setting
       fractions.

              .EQ
              chartype "binary" \[+-]
              define frac ! { $1 } over { $2 } !
              x = frac(- b \[+-] sqrt { b sup 2 - 4 a c }, 2 a)
              .EN

[1mSee also[0m
       “Typesetting  Mathematics—User’s  Guide”  (2nd  edition),  by  Brian W.
       Kernighan and Lorinda L. Cherry, 1978, AT&T Bell Laboratories Computing
       Science Technical Report No. 17.

       [4mThe[24m [4mTeXbook[24m, by Donald E.  Knuth,  1984,  Addison‐Wesley  Professional.
       Appendix  G  discusses  many of the parameters from section “Customiza‐
       tion” above in greater detail.

       [4mgroff_char[24m(7), particularly subsections “Logical symbols”,  “Mathemati‐
       cal  symbols”, and “Greek glyphs”, documents a variety of special char‐
       acter escape sequences useful in mathematical typesetting.

       [4mgroff[24m(1), [4mtroff[24m(1), [4mpic[24m(1), [4mgroff_font[24m(5)

groff 1.23.0                      5 July 2023                           [4meqn[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4meqn2graph[24m(1)                General Commands Manual               [4meqn2graph[24m(1)

[1mName[0m
       eqn2graph - convert an [4meqn[24m equation into a cropped image

[1mSynopsis[0m
       [1meqn2graph [22m[[1m-format [4m[22moutput‐format[24m] [[4mconvert‐argument[24m ...]

       [1meqn2graph --help[0m

       [1meqn2graph -v[0m
       [1meqn2graph --version[0m

[1mDescription[0m
       [4meqn2graph[24m reads a one‐line [4meqn[24m(1) equation from the standard input  and
       writes  an  image  file,  by default in Portable Network Graphics (PNG)
       format, to the standard output.

       The input EQN code should [4mnot[24m be preceded by the [1m.EQ  [22mmacro  that  nor‐
       mally  precedes it within [4mgroff[24m(1) macros; nor do you need to have dol‐
       lar‐sign or other delimiters around the equation.

       Arguments not recognized by [4meqn2graph[24m are passed to the ImageMagick  or
       GraphicsMagick  program  [4mconvert[24m(1).  By specifying these, you can give
       your image a border, set the image’s pixel density,  or  perform  other
       useful transformations.

       The  output image is clipped using [4mconvert[24m’s [1m-trim [22moption to the small‐
       est possible bounding box that contains all the black pixels.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-format [4m[22moutput‐format[0m
              Write  the  image  in [4moutput‐format[24m, which must be understood by
              [4mconvert[24m; the default is PNG.

[1mEnvironment[0m
       [4mGROFF_TMPDIR[0m
       [4mTMPDIR[0m
       [4mTMP[0m
       [4mTEMP[24m   These environment variables are searched in the given  order  to
              determine  the  directory where temporary files will be created.
              If none are set, [4m/tmp[24m is used.

[1mAuthors[0m
       [4meqn2graph[24m was written by Eric S. Raymond ⟨esr@thyrsus.com⟩, based on  a
       recipe for [4mpic2graph[24m(1), by W. Richard Stevens.

[1mSee also[0m
       [4mpic2graph[24m(1), [4mgrap2graph[24m(1), [4meqn[24m(1), [4mgroff[24m(1), [4mconvert[24m(1)

groff 1.23.0                      5 July 2023                     [4meqn2graph[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgdiffmk[24m(1)                  General Commands Manual                 [4mgdiffmk[24m(1)

[1mName[0m
       gdiffmk - mark differences between [4mgroff[24m/[4mnroff[24m/[4mtroff[24m files

[1mSynopsis[0m
       [1mgdiffmk [22m[[1m-a [4m[22madd‐mark[24m] [[1m-c [4m[22mchange‐mark[24m] [[1m-d [4m[22mdelete‐mark[24m] [[1m-x [4m[22mdiff‐[0m
               [4mcommand[24m] [[1m-D [22m[[1m-B[22m] [[1m-M [4m[22mmark1[24m [4mmark2[24m]] [[1m--[22m] [4mfile1[24m [4mfile2[24m [[4moutput[24m]

       [1mgdiffmk --help[0m

       [1mgdiffmk --version[0m

[1mDescription[0m
       [4mgdiffmk[24m  compares two [4mroff[24m(7) documents, [4mfile1[24m and [4mfile2[24m, and creates a
       [4mroff[24m document consisting of [4mfile2[24m with added margin character ([1m.mc[22m) re‐
       quests indicating output lines that differ from [4mfile1.[24m  If the [4mfile1[24m or
       [4mfile2[24m argument is “[1m-[22m”, [4mgdiffmk[24m reads the standard input stream for that
       input.  If the [4moutput[24m operand is present, [4mgdiffmk[24m writes  output  to  a
       file  of  that  name.  If it is “[1m-[22m” or absent, [4mgdiffmk[24m writes output to
       the standard output stream.  “[1m-[22m” cannot be both  an  input  and  output
       operand.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message and [1m--version [22mshows version informa‐
       tion; both exit afterward.

       [1m-a [4m[22madd‐mark[0m
              Use [4madd‐mark[24m for source lines not in [4mfile1[24m but present in [4mfile2[24m.
              Default: “[1m+[22m”.

       [1m-B     [22mBy default, the deleted texts marked by the [1m-D [22moption  end  with
              an  added  [4mroff[24m break request, [1m.br[22m, to ensure that the deletions
              are marked properly.  This is the only  way  to  guarantee  that
              deletions  and  small  changes get flagged.  This option directs
              the program not to insert these breaks; it makes no sense to use
              it without [1m-D[22m.

       [1m-c [4m[22mchange‐mark[0m
              Use [4mchange‐mark[24m for changed source lines.  Default: “[1m|[22m”.

       [1m-d [4m[22mdelete‐mark[0m
              Use the [4mdelete‐mark[24m for deleted source lines.  Default: “[1m*[22m”.

       [1m-D     [22mShow the deleted portions from changed and deleted text.

       [1m-M [4m[22mmark1[24m [4mmark2[0m
              Change the delimiting marks for the  [1m-D  [22moption.   It  makes  no
              sense  to use this option without [1m-D[22m.  Default delimiting marks:
              “[1m[[[22m” ... “[1m]][22m”.

       [1m-x [4m[22mdiff‐command[0m
              Use the [4mdiff‐command[24m command to perform the comparison of  [4mfile1[0m
              and  [4mfile2[24m.   In  particular, [4mdiff‐command[24m should accept the GNU
              [4mdiff[24m(1) [1m-D [22moption.  Default: [1mdiff[22m.

       [1m--     [22mTreat all subsequent arguments as file names, even if they begin
              with “[1m-[22m”.

[1mBugs[0m
       The output is not necessarily compatible with all  macro  packages  and
       all  preprocessors.   A  workaround  that  often overcomes preprocessor
       problems is to run [4mgdiffmk[24m on the output of all the  preprocessors  in‐
       stead of the input source.

       [4mgdiffmk[24m  relies  on the [1m-D [22moption of GNU [4mdiff[24m to make a merged “#ifdef”
       output format.  Busybox [4mdiff[24m is known to not support it.  Also see  the
       [1m-x [4m[22mdiff‐command[24m option.

[1mAuthors[0m
       [4mgdiffmk[24m was written by Mike Bianchi ⟨MBianchi@Foveal.com⟩, now retired.
       It is maintained by the [4mgroff[24m developers.

[1mSee also[0m
       [4mgroff[24m(1), [4mnroff[24m(1), [4mgtroff[24m(1), [4mroff[24m(7), [4mdiff[24m(1)

groff 1.23.0                      5 July 2023                       [4mgdiffmk[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mglilypond[24m(1)                General Commands Manual               [4mglilypond[24m(1)

[1mName[0m
       glilypond - embed LilyPond musical notation in [4mgroff[24m documents

[1mSynopsis[0m
       [1mglilypond [22m[[1m-k[22m] [{[1m--ly2eps[22m|[1m--pdf2eps[22m}] [[1m-e [4m[22mdirectory[24m] [[1m-o [4m[22moutput‐file[24m]
                 [[1m-p [4m[22mfilename‐prefix[24m] [[1m-t [4m[22mtdir[24m] [{[1m-v[22m|[1m-V[22m}] [[1m--[22m] [[4mfile[24m ...]
       [1mglilypond [22m[{[1m--ly2eps[22m|[1m--pdf2eps[22m}] [[1m--eps_dir [4m[22mdirectory[24m] [[1m--keep_all[22m]
                 [[1m--output [4m[22moutput‐file[24m] [[1m--prefix [4m[22mfilename‐prefix[24m] [[1m--temp_dir[0m
                 [4mtdir[24m] [[1m--verbose[22m] [[1m--[22m] [[4mfile[24m ...]

       [1mglilypond -?[0m
       [1mglilypond -h[0m
       [1mglilypond --help[0m
       [1mglilypond --usage[0m

       [1mglilypond -l[0m
       [1mglilypond --license[0m

       [1mglilypond --version[0m

[1mDescription[0m
       [4mglilypond[24m  is  a  [4mgroff[24m(7)  preprocessor  that enables the embedding of
       LilyPond music scores in [4mgroff[24m documents.  If no operands are given, or
       if [4mfile[24m is “[1m-[22m”, [4mglilypond[24m reads the standard input stream.   A  double‐
       dash  argument (“[1m--[22m”) causes all subsequent arguments to be interpreted
       as [4mfile[24m operands, even if their names start with a dash.

[1mUsage[0m
       At present, [4mglilypond[24m works with the [4mgroff[24m [1mps[22m, [1mdvi[22m, [1mhtml[22m, and [1mxhtml [22mde‐
       vices.  The [1mlbp [22mand [1mlj4 [22mdevices are untested.  Unfortunately,  the  [1mpdf[0m
       device does not yet work.

[1mOption overview[0m
       [1m-?[22m|[1m-h[22m|[1m--help[22m|[1m--usage[0m
              Display usage information and exit.

       [1m--version[0m
              Display version information and exit.

       [1m-l[22m|[1m--license[0m
              Display copyright license information and exit.

   [1mOptions for building EPS files[0m
       [1m--ly2eps[0m
              Direct  [4mlilypond[24m(1)  to  create  Encapsulated  PostScript  (EPS)
              files.  This is the default.

       [1m--pdf2eps[0m
              The program [4mglilypond[24m generates a PDF file using [4mlilypond[24m.  Then
              the EPS file is generated by [4mpdf2ps[24m and [4mps2eps[24m.

   [1mDirectories and files[0m
       [1m-e[22m|[1m--eps_dir [4m[22mdirectory_name[0m
              Normally all [4mEPS[24m files are  sent  to  the  temporary  directory.
              With  this option, you can generate your own directory, in which
              all useful [4mEPS[24m files are send.  So at last, the temporary direc‐
              tory can be removed.

       [1m-p[22m|[1m--prefix [4m[22mbegin_of_name[0m
              Normally all temporary files get names that start with the [1mly[4m[22m...[0m
              prefix.  With this option, you can freely change this prefix.

       [1m-k[22m|[1m--keep_all[0m
              Normally all temporary files without the [4meps[24m files are  deleted.
              With  this  option,  all  generated files either by the [4mlilypond[0m
              program or other format transposers are kept.

       [1m-t[22m|[1m--temp_dir [4m[22mdir[0m
              With this option, you call a directory that is the base for  the
              temporary  directory.  This directory name is used as is without
              any extensions.  If this directory does not exist it is be  cre‐
              ated.  The temporary directory is created by Perl’s security op‐
              erations  directly  under this directory.  In this temporary di‐
              rectory, the temporary files are stored.

   [1mOutput[0m
       [1m-o[22m|[1m--output [4m[22mfile_name[0m
              Normally all [4mgroff[24m output of this program  is  sent  to  [1mSTDOUT[22m.
              With  this  option, that can be changed, such that the output is
              stored into a file named in the option argument [4mfile_name[24m.

       [1m-v[22m|[1m-V[22m|[1m--verbose[0m
              A lot more of information is sent to STDERR.

   [1mShort option collections[0m
       The argument handling of options

       [4mShort[24m [4moptions[24m are arguments that start with a single dash [1m-[22m.   Such  an
       argument can consist of arbitrary many options without option argument,
       composed  as  a  collection  of  option characters following the single
       dash.

       Such a collection can be terminated by an option character that expects
       an option argument.  If this option character is not the last character
       of the argument, the following final part of the argument is the option
       argument.  If it is the last character of the argument, the next  argu‐
       ment is taken as the option argument.

       This is the standard for [4mPOSIX[24m and [4mGNU[24m option management.

       For example,

       [1m-kVe [4m[22msome_dir[0m
              is  a  collection  of the short options [1m-k [22mand [1m-V [22mwithout option
              argument, followed by the short option [1m-e [22mwith  option  argument
              that  is  the  following part of the argument [4msome_dir[24m.  So this
              argument could also be written as several  arguments  [1m-k  -V  -e[0m
              [4msome_dir[24m.

   [1mHandling of long options[0m
       Arguments that start with a double dash [1m-- [22mare so‐called [4mlong[24m [4moptions[24m [4mR[0m
       [4m.[24m  Each double dash argument can only have a single long option.

       [4mLong[24m  [4moptions[24m  have or have not an option argument.  An option argument
       can be the next argument or can be appended with an equal sign [1m= [22mto the
       same argument as the long option.

       [1m--help [22mis a long option without an option argument.

       [1m--eps_dir [4m[22msome_dir[0m
       [1m--eps_dir=[4m[22msome_dir[0m
              is the long option [1m--eps_dir [22mwith the option argument [4msome_dir[24m.

       Moreover the program allows abbreviations of long options, as  much  as
       possible.

       The  [4mlong[24m [4moption[24m [1m--keep_all [22mcan be abbreviated from [1m--keep_al [22mup to [1m--k[0m
       because the program does not have another [4mlong[24m [4moption[24m whose name starts
       with the character [1mk[22m.

       On the other hand, the option [1m--version [22mcannot be  abbreviated  further
       than [1m--vers [22mbecause there is also the [4mlong[24m [4moption[24m [1m--verbose [22mthat can be
       abbreviated up to [1m--verb[22m.

       An  option  argument  can  also  be appended to an abbreviation.  So is
       [1m--e=[4m[22msome_dir[24m the same as [1m--eps_dir [4m[22msome_dir[24m.

       Moreover the program allows an arbitrary usage of upper and lower  case
       in the option name.  This is [4mPerl[24m style.

       For  example,  the  [4mlong[24m  [4moption[24m  [1m--keep_all  [22mcan as well be written as
       [1m--Keep_All [22mor even as an abbreviation like [1m--KeE[22m.

[1mLilyPond regions in [4mroff[24m input[0m
   [1mIntegrated LilyPond code[0m
       A [4mlilypond[24m part within a structure written in the [4mgroff[24m language is the
       whole part between the marks
              [1m.lilypond start[0m
       and
              [1m.lilypond end[0m
       A [4mgroff[24m input can have several of these [4mlilypond[24m parts.

       When processing such a [4mlilypond[24m part between [1m.lilypond start [22mand [1m.lily‐[0m
       [1mpond end [22mwe say that the [1mglilypond [22mprogram is in [4mlilypond[24m [4mmode[24m.

       These [4mlilypond[24m parts are sent into temporary [4mlilypond[24m  files  with  the
       file name extension [1m.ly[22m.  These files are transformed later on into [4mEPS[0m
       files.

   [1mInclusion of [4m.ly[24m files[0m
       An  additional  command  line  for  file inclusion of [4mlilypond[24m files is
       given by
       [1m.lilypond include [4m[22mfile_name[0m
       in [4mgroff[24m input.  For each such [4minclude[24m command, one  file  of  [4mlilypond[0m
       code  can  be  included into the [4mgroff[24m code.  Arbitrarily many of these
       commands can be included in the [4mgroff[24m input.

       These include commands can only be used  outside  the  [4mlilypond[24m  parts.
       Within the [4mlilypond[24m [4mmode[24m, this inclusion is not possible.  So [1m.lilypond[0m
       [1minclude  [22mmay not be used in [4mlilypond[24m [4mmode[24m, i.e. between [1m.lilypond start[0m
       and [1m.lilypond end[22m.  These included [4mly[24m‐files are also  transformed  into
       [4mEPS[24m files.

[1mGenerated files[0m
       By  the  transformation process of [4mlilypond[24m parts into [4mEPS[24m files, there
       are many files generated.  By default, these files are regarded as tem‐
       porary files and as such stored in a temporary directory.

       This process can be changed by command‐line options.

   [1mCommand‐line options for directories[0m
       The temporary directory for this program is  either  created  automati‐
       cally or can be named by the option [1m-t[22m|[1m--temp_dir [4m[22mdir[24m.

       Moreover, the [4mEPS[24m files that are later on referred by [1m.PSPIC [22mcommand in
       the  final [4mgroff[24m output can be stored in a different directory that can
       be set by the command‐line option  [1m-e[22m|[1m--eps_dir  [4m[22mdirectory_name[24m.   With
       this  option,  the temporary directory can be removed completely at the
       end of the program.

       The beginning of the names of the temporary files can  be  set  by  the
       command‐line options [1m-p [22mor [1m--prefix[22m.

       All  of  the  temporary files except the [4mEPS[24m files are deleted finally.
       This  can  be  changed  by  setting  the  command‐line  options  [1m-k  [22mor
       [1m--keep_files[22m.  With this, all temporary files and directories are kept,
       not deleted.

       These  [4mEPS[24m  files are stored in a temporary or [4mEPS[24m directory.  But they
       cannot be deleted by the transformation process because they are needed
       for the display which can take a long time.

[1mTransformation processes for generating EPS files[0m
   [1mMode pdf2eps[0m
       This mode is the actual default and can also be chosen  by  the  option
       [1m--pdf2eps[22m.

       In  this mode, the [1m.ly [22mfiles are transformed by the [4mlilypond[24m(1) program
       into [4mPDF[24m files, using
              [1mlilypond --pdf --output=[4m[22mfile‐name[0m
       for each [1m.ly [22mfile.  The [4mfile‐name[24m must be provided without  the  exten‐
       sion [1m.pdf[22m.  By this process, a file [4mfile‐name[24m[1m.pdf [22mis generated.

       The  next step is to transform these [4mPDF[24m files into a [4mPS[24m file.  This is
       done by the [4mpdf2ps[24m(1) program using
              $ [1mpdf2ps [4m[22mfile‐name[24m[1m.pdf [4m[22mfile‐name[24m[1m.pds[0m
       The next step creates an [4mEPS[24m file from the [4mPS[24m file.  This  is  done  by
       the [4mps2eps[24m(1) program using
              $ [1mps2eps [4m[22mfile‐name[24m[1m.ps[0m

       By  that, a file [4mfile‐name[24m[1m.eps [22mis created for each [4mlilypond[24m part in the
       [4mgroff[24m file or standard input.

       The last step to be done is replacing all [4mlilypond[24m parts by  the  [4mgroff[0m
       command
              [1m.PSPIC [4m[22mfile‐name[24m[1m.eps[0m

   [1mMode ly2eps[0m
       In  earlier  time, this mode was the default.  But now it does not work
       any more, so accept the new default [4mpdf2eps[24m.  For  testing,  this  mode
       can also be chosen by the [4mglilypond[24m option [1m--ly2eps[22m.

       In  this  mode,  the  [1m.ly [22mfiles are transformed by the [4mlilypond[24m program
       into many files of different formats, including [4meps[24m files, using
              $ [1mlilypond --ps -dbackend=eps -dgs-load-fonts --output=[4m[22mfile‐name[0m
       for each [1m.ly [22mfile.  The output [4mfile-name[24m must be  provided  without  an
       extension, its directory is temporary.

       There  are many [4mEPS[24m files created.  One having the complete transformed
       [1mly [22mfile, named [4mfile-name[24m[1m.eps[22m.

       Moreover there are [4mEPS[24m files for each page, named [4mfile-name[24m[1m-[4m[22mdigit[24m[1m.eps[22m.

       The last step to be done is replacing all [4mlilypond[24m parts by the collec‐
       tion of the corresponding [4mEPS[24m page files.  This is done by  [4mgroff[24m  com‐
       mands
       [1m.PSPIC [4m[22mfile‐name[24m[1m-[4m[22mdigit[24m[1m.eps[0m

[1mGenerated [4mgroff[24m output[0m
       The new [4mgroff[24m(7) structure generated by [4mglilypond[24m is either

       1)     sent  to  standard  output and can there be saved into a file or
              piped into [4mgroff[24m(1) or

       2)     stored into a file by given the option [1m-o  | [22m--output [4mfile_name[0m

[1mAuthors[0m
       [4mglilypond[24m was written by Bernd Warken ⟨groff-bernd.warken-72@web.de⟩.

[1mSee also[0m
       [4mgroff[24m(1)
              describes the usage of the [4mgroff[24m command and  contains  pointers
              to further documentation of the [4mgroff[24m system.

       [4mgroff_tmac[24m(5)
              describes the [1m.PSPIC [22mrequest.

       [4mlilypond[24m(1)
              briefly  describes the [4mlilypond[24m command and contains pointers to
              further documentation.

       [4mpdf2ps[24m(1)
              transforms a [4mPDF[24m file into a [4mPostScript[24m format.

       [4mps2eps[24m(1)
              transforms a [4mPS[24m file into an [4mEPS[24m format.

groff 1.23.0                      5 July 2023                     [4mglilypond[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgperl[24m(1)                    General Commands Manual                   [4mgperl[24m(1)

[1mName[0m
       gperl - execute Perl commands in [4mgroff[24m documents

[1mSynopsis[0m
       [1mgperl [22m[[4mfile[24m ...]

       [1mgperl -h[0m
       [1mgperl --help[0m

       [1mgperl -v[0m
       [1mgperl --version[0m

[1mDescription[0m
       This is a preprocessor for [4mgroff[24m(1).  It allows the use of [4mperl[24m(7) code
       in [4mgroff[24m(7) files.  The result of a [4mPerl[24m [4mpart[24m can be  stored  in  groff
       [4mstrings[24m  or  [4mnumerical[24m [4mregisters[24m based on the arguments at a final line
       of a [4mPerl[24m [4mpart[24m.

       If no operands are given, or if [4mfile[24m is “[1m-[22m”, [4mgperl[24m reads  the  standard
       input  stream.  A double‐dash argument (“[1m--[22m”) causes all subsequent ar‐
       guments to be interpreted as [4mfile[24m operands, even if their  names  start
       with  a  dash.   [1m-h  [22mand [1m--help [22mdisplay a usage message, whereas [1m-v [22mand
       [1m--version [22mdisplay version information; all exit afterward.

[1mPerl regions[0m
       [4mPerl[24m parts in [4mgroff[24m [4mfiles[24m are enclosed by two [1m.Perl [22mrequests with  dif‐
       ferent arguments, a [4mstarting[24m and an [4mending[24m command.

   [1mStarting Perl mode[0m
       The  starting [4mPerl[24m [4mrequest[24m can either be without arguments, or by a re‐
       quest that has the term [1mstart [22mas its only argument.

              •      [1m.Perl[0m

              •      [1m.Perl start[0m

   [1mEnding Perl mode without storage[0m
       A [1m.Perl [22mcommand line with an argument different from [1mstart  [22mfinishes  a
       running  [4mPerl[24m [4mpart[24m.  Of course, it would be reasonable to add the argu‐
       ment [1mstop[22m; that’s possible, but not necessary.

              •      [1m.Perl stop[0m

              •      [1m.Perl [4m[22mother_than_start[0m
       The argument [4mother_than_start[24m can  additionally  be  used  as  a  [4mgroff[0m
       string variable name for storage — see next section.

   [1mEnding Perl mode with storage[0m
       A useful feature of [4mgperl[24m is to store one or more results from the [4mPerl[0m
       [4mmode[24m.

       The output of a [4mPerl[24m [4mpart[24m can be got with backticks [1m`...`[22m.

       This  program  collects all printing to STDOUT (normal standard output)
       by the Perl [1mprint [22mprogram.  This pseudo‐printing output can  have  sev‐
       eral lines, due to printed line breaks with [1m\n[22m.  By that, the output of
       a  Perl  run should be stored into a Perl array, with a single line for
       each array member.

       This Perl array output can be stored by [4mgperl[24m in either

       [4mgroff[24m [4mstrings[0m
              by creating a groff command [1m.ds[0m

       [4mgroff[24m [4mregister[0m
              by creating a groff command [1m.rn[0m

       The storage modes can be determined by arguments of  a  final  stopping
       [1m.Perl  [22mcommand.   Each  argument [1m.ds [22mchanges the mode into [4mgroff[24m [4mstring[0m
       and [1m.nr [22mchanges the mode into [4mgroff[24m [4mregister[24m for all  following  output
       parts.

       By default, all output is saved as strings, so [1m.ds [22mis not really needed
       before  the  first  [1m.nr [22mcommand.  That suits to [4mgroff[24m(7), because every
       output can be saved as [4mgroff[24m string, but the registers can be very  re‐
       strictive.

       In [4mstring[24m [4mmode[24m, [4mgperl[24m generates a [4mgroff[24m [4mstring[24m storage line
              [1m.ds [4m[22mvar_name[24m [4mcontent[0m
       In [4mregister[24m [4mmode[24m the following groff command is generated
              [1m.nr [4m[22mvar_name[24m [4mcontent[0m

       We present argument collections in the following.  You can add as first
       argument for all [1mstop[22m.  We omit this additional element.

       [1m.Perl .ds [4m[22mvar_name[0m
              This  will  store  1  output  line  into  the groff string named
              [4mvar_name[24m by the automatically created command
                     [1m.ds [4m[22mvar_name[24m [4moutput[0m

       [1m.Perl [4m[22mvar_name[0m
              If [4mvar_name[24m is different from [1mstart [22mthis is  equivalent  to  the
              former  command, because the string mode is string with [1m.ds [22mcom‐
              mand.  default.

       [1m.Perl [4m[22mvar_name1[24m [4mvar_name2[0m
              This will store 2 output lines into groff string names [4mvar_name1[0m
              and [4mvar_name2[24m, because the default mode [1m.ds [22mis active, such that
              no [1m.ds [22margument is needed.  Of course, this is equivalent to
                     [1m.Perl .ds [4m[22mvar_name1[24m [4mvar_name2[0m
              and
                     [1m.Perl .ds [4m[22mvar_name1[24m [1m.ds [4m[22mvar_name2[0m

       [1m.Perl .nr [4m[22mvar_name1[24m [4mvarname2[0m
              stores both variables as register variables.  [4mgperl[24m generates
              [1m.nr [4m[22mvar_name1[24m [4moutput_line1[0m
              [1m.nr [4m[22mvar_name2[24m [4moutput_line2[0m

       [1m.Perl .nr [4m[22mvar_name1[24m [1m.ds [4m[22mvar_name2[0m
              stores the 1st argument as [4mregister[24m and the second as [4mstring[24m by
              [1m.nr [4m[22mvar_name1[24m [4moutput_line1[0m
              [1m.ds [4m[22mvar_name2[24m [4moutput_line2[0m

[1mExample[0m
       A possible [4mPerl[24m [4mpart[24m in a [4mroff[24m [4mfile[24m could look like that:
              before
              .Perl start
              my $result = 'some data';
              print $result;
              .Perl stop .ds string_var
              after

       This stores  the  result  [1m”some  data”  [22minto  the  [4mroff[24m  [4mstring[24m  called
       [1mstring_var[22m, such that the following line is printed:
              .ds string_var some data
       by [4mgperl[24m as food for the coming [4mgroff[24m run.

       A [4mPerl[24m [4mpart[24m with several outputs is:
              .Perl start
              print ”first\n”;
              print ”second line\n”;
              print ”3\n”;
              .Perl var1 var2 .nr var3
       This  stores 3 printed lines into 3 [4mgroff[24m strings.  [1mvar1[22m,[1mvar2[22m,[1mvar3[22m.  So
       the following [4mgroff[24m command lines are created:
              .ds var1 first
              .ds var2 second line
              .nr var3 3

[1mAuthors[0m
       [4mgperl[24m was written by Bernd Warken ⟨groff-bernd.warken-72@web.de⟩.

[1mSee also[0m
       Man pages related to [4mgroff[24m are [4mgroff[24m(1), [4mgroff[24m(7), and [4mgrog[24m(1).

       Documents related to [4mPerl[24m are [4mperl[24m(1), [4mperl[24m(7).

groff 1.23.0                      5 July 2023                         [4mgperl[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgpinyin[24m(1)                  General Commands Manual                 [4mgpinyin[24m(1)

[1mName[0m
       gpinyin - use Hanyu Pinyin Chinese in [4mgroff[24m documents

[1mSynopsis[0m
       [1mgpinyin [22m[[4mfile[24m ...]

       [1mgpinyin -h[0m
       [1mgpinyin --help[0m

       [1mgpinyin -v[0m
       [1mgpinyin --version[0m

[1mDescription[0m
       [4mgpinyin[24m is a preprocessor for [4mgroff[24m(1) that facilitates  use  of  Hanyu
       Pinyin  in [4mgroff[24m(7) files.  Pinyin is a method for writing the Mandarin
       Chinese language with the Latin alphabet.  Mandarin  consists  of  more
       than  four hundred base syllables, each spoken with one of five differ‐
       ent tones.  Changing the tone applied to the syllable generally  alters
       the  meaning of the word it forms.  In Pinyin, a syllable is written in
       the Latin alphabet and a numeric tone indicator can be appended to each
       syllable.

       Each [4minput‐file[24m is a file name or the character “[1m-[22m”  to  indicate  that
       the  standard input stream should be read.  As usual, the argument “[1m--[22m”
       can be used in order to force interpretation of all remaining arguments
       as file names, even if an [4minput‐file[24m argument begins with  a  “[1m-[22m”.   [1m-h[0m
       and [1m--help [22mdisplay a usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

   [1mPinyin sections[0m
       Pinyin  sections  in  [4mgroff[24m  files are enclosed by two [1m.pinyin [22mrequests
       with different arguments.  The starting request is
              .pinyin start
       or
              .pinyin begin
       and the ending request is
              .pinyin stop
       or
              .pinyin end
       .

   [1mSyllables[0m
       In Pinyin, each syllable is represented by one  to  six  letters  drawn
       from  the  fifty‐two  upper‐ and lowercase letters of the Unicode basic
       Latin character set, plus the letter “U” with dieresis (umlaut) in both
       cases—in other words, the members of the set “[a–zA–ZüÜ]”.

       In [4mgroff[24m input, all basic Latin letters are written as themselves.  The
       “u with dieresis” can be written as “\[:u]” in lowercase or “\[:U]”  in
       uppercase.  Within [1m.pinyin [22msections, [4mgpinyin[24m supports the form “ue” for
       lowercase and the forms “Ue” and “UE” for uppercase.

   [1mTones[0m
       Each syllable has exactly one of five [4mtones[24m.  The fifth tone is not ex‐
       plicitly  written at all, but each of the first through fourth tones is
       indicated with a diacritic above a specific vowel within the syllable.

       In a [4mgpinyin[24m source file, these tones are written by adding  a  numeral
       in  the  range  0 to 5 after the syllable.  The tone numbers 1 to 4 are
       transformed into accents above vowels in the output.  The tone  numbers
       0 and 5 are synonymous.

       The tones are written as follows.

       Tone     Description      Diacritic   Example Input   Example Output
       ─────────────────────────────────────────────────────────────────────
       first    flat             ¯           ma1             mā
       second   rising           ´           ma2             má
       third    falling‐rising   ˇ           ma3             mǎ
       fourth   falling          `           ma4             mà
       fifth    neutral          (none)      ma0             ma
                                             ma5

       The  neutral tone number can be omitted from a word‐final syllable, but
       not otherwise.

[1mAuthors[0m
       [4mgpinyin[24m was written by Bernd Warken ⟨groff-bernd.warken-72@web.de⟩.

[1mSee also[0m
       Useful documents on the World Wide Web related to Pinyin include
           [4mPinyin[24m [4mto[24m [4mUnicode[24m ⟨http://www.foolsworkshop.com/ptou/index.html⟩,
           [4mOn‐line[24m [4mChinese[24m [4mTools[24m ⟨http://www.mandarintools.com/⟩,
           [4mPinyin.info:[24m [4ma[24m [4mguide[24m [4mto[24m [4mthe[24m [4mwriting[24m [4mof[24m [4mMandarin[24m [4mChinese[24m [4min[24m [4mroman‐[0m
           [4mization[24m ⟨http://www.pinyin.info/index.html⟩,
           “Where  do  the  tone  marks  go?”   ⟨http://www.pinyin.info/rules/
           where.html⟩,
           [4mpinyin.txt[24m  from the CJK macro package for TeX ⟨http://git.savannah
           .gnu.org/gitweb/?p=cjk.git;a=blob_plain;f=doc/pinyin.txt;hb=HEAD⟩,
       and
           [4mpinyin.sty[24m from the CJK macro package for TeX ⟨http://git.savannah
           .gnu.org/gitweb/?p=cjk.git;a=blob_plain;f=texinput/pinyin.sty
           ;hb=HEAD⟩.

       [4mgroff[24m(1) and [4mgrog[24m(1) explain how to view [4mroff[24m documents.

       [4mgroff[24m(7) and [4mgroff_char[24m(7) are comprehensive  references  covering  the
       language  elements of GNU [4mtroff[24m and the available glyph repertoire, re‐
       spectively.

groff 1.23.0                      5 July 2023                       [4mgpinyin[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrap2graph[24m(1)               General Commands Manual              [4mgrap2graph[24m(1)

[1mName[0m
       grap2graph - convert a [4mgrap[24m diagram into a cropped image

[1mSynopsis[0m
       [1mgrap2graph [22m[[1m-unsafe[22m] [[1m-format [4m[22moutput‐format[24m] [[4mconvert‐argument[24m ...]

       [1mgrap2graph --help[0m

       [1mgrap2graph -v[0m
       [1mgrap2graph --version[0m

[1mDescription[0m
       [4mgrap2graph[24m reads a [4mgrap[24m(1) program from the standard input  and  writes
       an image file, by default in Portable Network Graphics (PNG) format, to
       the standard output.

       The  input  GRAP code should [4mnot[24m be wrapped with the [1m.G1 [22mand [1m.G2 [22mmacros
       that normally guard it within [4mgroff[24m(1) documents.

       Arguments not recognized by [4mgrap2graph[24m are passed to the ImageMagick or
       GraphicsMagick program [4mconvert[24m(1).  By specifying these, you  can  give
       your  image  a  border, set the image’s pixel density, or perform other
       useful transformations.

       The output image is clipped using [4mconvert[24m’s [1m-trim [22moption to the  small‐
       est possible bounding box that contains all the black pixels.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-format [4m[22moutput‐format[0m
              Write the image in [4moutput‐format[24m, which must  be  understood  by
              [4mconvert[24m; the default is PNG.

       [1m-unsafe[0m
              Run [4mgroff[24m in [4munsafe[24m mode, enabling the PIC command [1msh [22mto execute
              arbitrary  Unix  shell commands.  The [4mgroff[24m default is to forbid
              this.

[1mEnvironment[0m
       [4mGROFF_TMPDIR[0m
       [4mTMPDIR[0m
       [4mTMP[0m
       [4mTEMP[24m   These environment variables are searched in the given  order  to
              determine  the  directory where temporary files will be created.
              If none are set, [4m/tmp[24m is used.

[1mAuthors[0m
       [4mgrap2graph[24m was written by Eric S. Raymond ⟨esr@thyrsus.com⟩, based on a
       recipe for [4mpic2graph[24m(1), by W. Richard Stevens.

[1mSee also[0m
       [4mpic2graph[24m(1), [4meqn2graph[24m(1), [4mgrap[24m(1), [4mpic[24m(1), [4mgroff[24m(1), [4mconvert[24m(1)

groff 1.23.0                      5 July 2023                    [4mgrap2graph[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrn[24m(1)                      General Commands Manual                     [4mgrn[24m(1)

[1mName[0m
       grn - embed Gremlin images in [4mgroff[24m documents

[1mSynopsis[0m
       [1mgrn [22m[[1m-C[22m] [[1m-T [4m[22mdev[24m] [[1m-M [4m[22mdir[24m] [[1m-F [4m[22mdir[24m] [[4mfile[24m ...]

       [1mgrn -?[0m
       [1mgrn --help[0m

       [1mgrn -v[0m
       [1mgrn --version[0m

[1mDescription[0m
       [4mgrn[24m is a preprocessor for including [4mgremlin[24m pictures in [4mtroff[24m(1) input.
       [4mgrn[24m writes to standard output, processing only input lines between  two
       that  start  with  [1m.GS  [22mand [1m.GE[22m.  Those lines must contain [4mgrn[24m commands
       (see below).  These macros request a [4mgremlin[24m file; the picture in  that
       file  is  converted  and  placed in the [4mtroff[24m input stream.  [1m.GS [22mmay be
       called with a [1mC[22m, [1mL[22m, or [1mR [22margument to center,  left‐,  or  right‐justify
       the  whole  [4mgremlin[24m  picture (the default is to center).  If no [4mfile[24m is
       mentioned, the standard input is read.  At the end of the picture,  the
       position  on the page is the bottom of the [4mgremlin[24m picture.  If the [4mgrn[0m
       entry is ended with [1m.GF [22minstead of [1m.GE[22m, the position is left at the top
       of the picture.

       Currently only the [4mme[24m macro package has support for [1m.GS[22m, [1m.GE[22m, and [1m.GF[22m.

       [4mgrn[24m produces drawing escape sequences that use [4mgroff[24m’s color scheme ex‐
       tension ([1m\D'F [22m...[1m'[22m), and thus may not work with other [4mtroff[24ms.

   [4m[1mgrn[24m commands[0m
       Each input line between [1m.GS [22mand [1m.GE [22mmay have one [4mgrn[24m command.  Commands
       consist of one or two strings  separated  by  white  space,  the  first
       string  being  the command and the second its operand.  Commands may be
       upper‐ or lowercase and abbreviated down to one character.

       Commands that affect  a  picture’s  environment  (those  listed  before
       “[1mdefault[22m”,  see  below) are only in effect for the current picture: the
       environment is reinitialized to the defaults at the start of  the  next
       picture.  The commands are as follows.

       [1m1 [4m[22mN[0m
       [1m2 [4m[22mN[0m
       [1m3 [4m[22mN[0m
       [1m4 [4m[22mN[24m    Set  [4mgremlin[24m’s text size number 1 (2, 3, or 4) to [4mN[24m points.  The
              default is 12 (16, 24, and 36, respectively).

       [1mroman [4m[22mf[0m
       [1mitalics [4m[22mf[0m
       [1mbold [4m[22mf[0m
       [1mspecial [4m[22mf[0m
              Set the roman (italics, bold, or special) font to [4mtroff[24m’s font [4mf[0m
              (either a name or number).  The default is R (I, B, and  S,  re‐
              spectively).

       [1ml [4m[22mf[0m
       [1mstipple [4m[22mf[0m
              Set the stipple font to [4mtroff[24m’s stipple font [4mf[24m (name or number).
              The  command  [1mstipple [22mmay be abbreviated down as far as “[1mst[22m” (to
              avoid confusion with “[1mspecial[22m”).  There is [4mno[24m default for  stip‐
              ples (unless one is set by the “[1mdefault[22m” command), and it is in‐
              valid  to include a [4mgremlin[24m picture with polygons without speci‐
              fying a stipple font.

       [1mx [4m[22mN[0m
       [1mscale [4m[22mN[0m
              Magnify the picture (in addition to any  default  magnification)
              by  [4mN[24m,  a  floating‐point  number larger than zero.  The command
              [1mscale [22mmay be abbreviated down to “[1msc[22m”.

       [1mnarrow [4m[22mN[0m
       [1mmedium [4m[22mN[0m
       [1mthick [4m[22mN[0m
              Set the thickness of [4mgremlin[24m’s narrow (medium and thick, respec‐
              tively) lines to [4mN[24m times 0.15pt (this value can  be  changed  at
              compile  time).  The default is 1.0 (3.0 and 5.0, respectively),
              which corresponds to 0.15pt (0.45pt and  0.75pt,  respectively).
              A  thickness  value  of zero selects the smallest available line
              thickness.  Negative values cause the line thickness to be  pro‐
              portional to the current point size.

       [1mpointscale [22m[[1moff[22m|[1mon[22m]
              Scale  text  to  match  the  picture.   Gremlin  text is usually
              printed in the point size specified with the commands [1m1[22m,  [1m2[22m,  [1m3[22m,
              or [1m4[22m, regardless of any scaling factors in the picture.  Setting
              [1mpointscale  [22mwill cause the point sizes to scale with the picture
              (within [4mtroff[24m’s limitations, of course).  An operand of anything
              but [1moff [22mwill turn text scaling on.

       [1mdefault[0m
              Reset the picture environment defaults to the  settings  in  the
              current picture.  This is meant to be used as a global parameter
              setting  mechanism at the beginning of the [4mtroff[24m input file, but
              can be used at any time to reset the default settings.

       [1mwidth [4m[22mN[0m
              Force the picture to be [4mN[24m inches wide.  This overrides any scal‐
              ing factors present in the same picture.  “[1mwidth 0[22m” is ignored.

       [1mheight [4m[22mN[0m
              Force the picture to be [4mN[24m inches high, overriding other  scaling
              factors.   If  both  [1mwidth [22mand [1mheight [22mare specified, the tighter
              constraint will determine the scale of the picture.  [1mheight  [22mand
              [1mwidth  [22mcommands  are  not  saved with a “[1mdefault[22m” command.  They
              will, however, affect point size scaling if that option is set.

       [1mfile [4m[22mname[0m
              Get picture from [4mgremlin[24m file [4mname[24m located the current directory
              (or in the library directory; see the [1m-M [22moption above).  If mul‐
              tiple [1mfile [22mcommands are given, the last one controls.   If  [4mname[0m
              doesn’t  exist, an error message is reported and processing con‐
              tinues from the [1m.GE [22mline.

   [1mUsage with [4mgroff[0m
       Since [4mgrn[24m is a preprocessor, it has no access to elements of  formatter
       state, such as indentation, line length, type size, or register values.
       Consequently,  no  [4mtroff[24m  input  can  be placed between the [1m.GS [22mand [1m.GE[0m
       macros.  However, [4mgremlin[24m text elements are subsequently  processed  by
       [4mtroff[24m,  so anything valid in a single line of [4mtroff[24m input is valid in a
       line of [4mgremlin[24m text (barring the dot control character “.” at the  be‐
       ginning  of  a  line).  Thus, it is possible to have equations within a
       [4mgremlin[24m figure by including in the [4mgremlin[24m  file  [4meqn[24m  expressions  en‐
       closed by previously defined delimiters (e.g., “$$”).

       When using [4mgrn[24m along with other preprocessors, it is best to run [4mtbl[24m(1)
       before  [4mgrn[24m,  [4mpic[24m(1),  and/or  [4mideal[24m  to avoid overworking [4mtbl[24m.  [4meqn[24m(1)
       should always be run last.  [4mgroff[24m(1) will automatically run  preproces‐
       sors in the correct order.

       A  picture  is  considered  an entity, but that doesn’t stop [4mtroff[24m from
       trying to break it up if it falls off the end of a page.   Placing  the
       picture between “keeps” in the [4mme[24m macros will ensure proper placement.

       [4mgrn[24m  uses  [4mtroff[24m’s registers [1mg1 [22mthrough [1mg9 [22mand sets registers [1mg1 [22mand [1mg2[0m
       to the width and height of the [4mgremlin[24m figure (in device units)  before
       entering  the  [1m.GS  [22mmacro  (this is for those who want to rewrite these
       macros).

   [1mGremlin file format[0m
       There exist two distinct [4mgremlin[24m file formats: the original format  for
       AED  graphic  terminals, and the Sun or X11 version.  An extension used
       by the Sun/X11 version allowing reference points with negative  coordi‐
       nates  is  [4mnot[24m  compatible  with the AED version.  As long as a [4mgremlin[0m
       file does not contain negative coordinates, either format will be  read
       correctly by either version of [4mgremlin[24m or [4mgrn[24m.  The other difference in
       Sun/X11  format is the use of names for picture objects (e.g., [1mPOLYGON[22m,
       [1mCURVE[22m) instead of numbers.  Files representing  the  same  picture  are
       shown below.

                        sungremlinfile        gremlinfile
                        0 240.00 128.00       0 240.00 128.00
                        CENTCENT              2
                        240.00 128.00         240.00 128.00
                        185.00 120.00         185.00 120.00
                        240.00 120.00         240.00 120.00
                        296.00 120.00         296.00 120.00
                        *                     -1.00 -1.00
                        2 3                   2 3
                        10 A Triangle         10 A Triangle
                        POLYGON               6
                        224.00 416.00         224.00 416.00
                        96.00 160.00          96.00 160.00
                        384.00 160.00         384.00 160.00
                        *                     -1.00 -1.00
                        5 1                   5 1
                        0                     0
                        -1                    -1

       • The first line of each [4mgremlin[24m file contains either the string “[1mgrem‐[0m
         [1mlinfile[22m” (AED) or “[1msungremlinfile[22m” (Sun/X11).

       • The  second line of the file contains an orientation and [4mx[24m and [4my[24m val‐
         ues for a positioning point, separated by spaces.   The  orientation,
         either [1m0 [22mor [1m1[22m, is ignored by the Sun/X11 version.  [1m0 [22mmeans that [4mgrem‐[0m
         [4mlin[24m  will  display  things in horizontal format (a drawing area wider
         than it is tall, with a menu across the top).  [1m1 [22mmeans  that  [4mgremlin[0m
         will display things in vertical format (a drawing area taller than it
         is  wide,  with a menu on the left side).  [4mx[24m and [4my[24m are floating‐point
         values giving a positioning point to be used when this file  is  read
         into  another file.  The stuff on this line really isn’t all that im‐
         portant; a value of “[1m1 0.00 0.00[22m” is suggested.

       • The rest of the file consists of zero or more element specifications.
         After the last element specification is a line containing the  string
         “[1m-1[22m”.

       • Lines longer than 127 characters are truncated to that length.

   [1mElement specifications[0m
       • The  first line of each element contains a single decimal number giv‐
         ing the type of the element (AED) or its name (Sun/X11).

                    [4mgremlin[24m File Format: Object Type Specification
               ─────────────────────────────────────────────────────────
               AED Number   Sun/X11 Name           Description
                    [1m0       BOTLEFT        [22mbottom‐left‐justified text
                    [1m1       BOTRIGHT       [22mbottom‐right‐justified text
                    [1m2       CENTCENT       [22mcenter‐justified text
                    [1m3       VECTOR         [22mvector
                    [1m4       ARC            [22marc
                    [1m5       CURVE          [22mcurve
                    [1m6       POLYGON        [22mpolygon
                    [1m7       BSPLINE        [22mb‐spline
                    [1m8       BEZIER         [22mBézier
                   [1m10       TOPLEFT        [22mtop‐left‐justified text
                   [1m11       TOPCENT        [22mtop‐center‐justified text
                   [1m12       TOPRIGHT       [22mtop‐right‐justified text
                   [1m13       CENTLEFT       [22mleft‐center‐justified text
                   [1m14       CENTRIGHT      [22mright‐center‐justified text
                   [1m15       BOTCENT        [22mbottom‐center‐justified text

       • After the object type comes a variable number of lines, each specify‐
         ing a point used to display the element.  Each line contains an x‐co‐
         ordinate and a y‐coordinate in floating‐point  format,  separated  by
         spaces.   The  list  of points is terminated by a line containing the
         string “[1m-1.0 -1.0[22m” (AED) or a single asterisk, “[1m*[22m” (Sun/X11).

       • After the points comes a line containing two decimal  values,  giving
         the  brush  and size for the element.  The brush determines the style
         in which things are drawn.  For vectors, arcs, and curves  there  are
         six valid brush values.

                               [1m1   [22mthin dotted lines
                               [1m2   [22mthin dot‐dashed lines
                               [1m3   [22mthick solid lines
                               [1m4   [22mthin dashed lines
                               [1m5   [22mthin solid lines
                               [1m6   [22mmedium solid lines

         For  polygons,  one  more value, 0, is valid.  It specifies a polygon
         with an invisible border.  For text, the brush selects a font as fol‐
         lows.

                             [1m1   [22mroman (R font in [4mtroff[24m)
                             [1m2   [22mitalics (I font in [4mtroff[24m)
                             [1m3   [22mbold (B font in [4mtroff[24m)
                             [1m4   [22mspecial (S font in [4mtroff[24m)

         If you’re using [4mgrn[24m to run your pictures through [4mgroff[24m, the  font  is
         really  just a starting font.  The text string can contain formatting
         sequences like “\fI” or “\d” which may change the font (as well as do
         many other things).  For text, the size field is a decimal value  be‐
         tween  1  and  4.   It selects the size of the font in which the text
         will be drawn.  For polygons, this size field  is  interpreted  as  a
         stipple number to fill the polygon with.  The number is used to index
         into a stipple font at print time.

       • The  last line of each element contains a decimal number and a string
         of characters, separated by a single space.  The number is a count of
         the number of characters in the string.   This  information  is  used
         only  for  text elements, and contains the text string.  There can be
         spaces inside the text.  For arcs, curves, and vectors, the character
         count is zero ([1m0[22m), followed by exactly one space before the newline.

   [1mCoordinates[0m
       [4mgremlin[24m was designed for AED terminals, and its coordinates reflect the
       AED coordinate space.  For vertical pictures, [4mx[24m  values  range  116  to
       511,  and  [4my[24m  values  from 0 to 483.  For horizontal pictures, [4mx[24m values
       range from 0 to 511, and [4my[24m values from 0 to 367.  Although you  needn’t
       absolutely  stick  to  this  range, you’ll get better results if you at
       least stay in this vicinity.  Also, point lists  are  terminated  by  a
       point  of  (-1,  -1),  so  you shouldn’t ever use negative coordinates.
       [4mgremlin[24m writes out coordinates using the [4mprintf[24m(3) format “%f1.2”; it’s
       probably a good idea to use the same format if you want to  modify  the
       [4mgrn[24m code.

   [1mSun/X11 coordinates[0m
       There  is no restriction on the range of coordinates used to create ob‐
       jects in the Sun/X11 version of [4mgremlin[24m.  However, files with  negative
       coordinates [4mwill[24m cause problems if displayed on the AED.

[1mOptions[0m
       [1m-? [22mand [1m--help [22mdisplay a usage message, while [1m-v [22mand [1m--version [22mshow ver‐
       sion information; all exit afterward.

       [1m-C     [22mRecognize  [1m.GS [22mand [1m.GE [22m(and [1m.GF[22m) even when followed by a charac‐
              ter other than space or newline.

       [1m-F [4m[22mdir[24m Search [4mdir[24m for subdirectories [4mdev[24mname ([4mname[24m is the name  of  the
              output  driver) for the [4mDESC[24m file before the default font direc‐
              tories [4m/usr/share/groff/site-font[24m, [4m/usr/share/groff/1.23.0/font[24m,
              and [4m/usr/lib/font[24m.

       [1m-M [4m[22mdir[24m Prepend [4mdir[24m to the search path for [4mgremlin[24m files.   The  default
              search  path is the current directory, the home directory, [4m/usr/[0m
              [4mshare/groff/site-tmac[24m, and [4m/usr/share/groff/1.23.0/tmac[24m, in that
              order.

       [1m-T [4m[22mdev[24m Prepare device output using output driver [4mdev[24m.  The  default  is
              [1mps[22m.  See [4mgroff[24m(1) for a list of valid devices.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/dev[24mname[4m/DESC[0m
              describes the output device [4mname[24m.

[1mAuthors[0m
       David  Slattengren  and Barry Roitblat wrote the original Berkeley [4mgrn[24m.
       Daniel Senderowicz and Werner Lemberg modified it for [4mgroff[24m.

[1mSee also[0m
       [4mgremlin[24m(1), [4mgroff[24m(1), [4mpic[24m(1), [4mideal[24m(1)

groff 1.23.0                      5 July 2023                           [4mgrn[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrodvi[24m(1)                   General Commands Manual                  [4mgrodvi[24m(1)

[1mName[0m
       grodvi - [4mgroff[24m output driver for TeX DVI format

[1mSynopsis[0m
       [1mgrodvi [22m[[1m-dl[22m] [[1m-F [4m[22mdir[24m] [[1m-p [4m[22mpaper‐format[24m] [[1m-w [4m[22mn[24m] [[4mfile[24m ...]

       [1mgrodvi --help[0m

       [1mgrodvi -v[0m
       [1mgrodvi --version[0m

[1mDescription[0m
       The GNU [4mroff[24m DVI output driver translates the output of  [4mtroff[24m(1)  into
       TeX  DVI format.  Normally, [4mgrodvi[24m is invoked by [4mgroff[24m(1) when the lat‐
       ter is given the “[1m-T dvi[22m” option.  (In this installation, [1mps [22mis the de‐
       fault output device.)  Use [4mgroff[24m’s [1m-P [22moption to pass any options  shown
       above  to  [4mgrodvi[24m.   If no [4mfile[24m arguments are given, or if [4mfile[24m is “-”,
       [4mgrodvi[24m reads the standard input stream.  Output is written to the stan‐
       dard output stream.

       The DVI file generated by [4mgrodvi[24m can interpreted by any correctly writ‐
       ten DVI driver.  [4mtroff[24m drawing primitives are  implemented  using  [4mtpic[0m
       version  2  specials.   If the driver does not support these, [1m\D [22mescape
       sequences will not produce any output.

       Encapsulated PostScript (EPS) files can be  easily  included;  use  the
       [1mPSPIC  [22mmacro.   [4mpspic.tmac[24m  is  loaded  automatically by [4mdvi.tmac[24m.  See
       [4mgroff_tmac[24m(5).

       The default color used by the [1m\m [22mand  [1m\M  [22mescape  sequences  is  black.
       Currently,  the  stroke color for [1m\D [22mdrawing escape sequences is black;
       fill color values are translated to gray.

       In [4mgroff[24m, as in AT&T [4mtroff[24m, the [1m\N [22mescape sequence can be used  to  ac‐
       cess any glyph in the current font by its position in the corresponding
       TFM file.

       By design, the DVI format doesn’t care about the physical dimensions of
       the  output  medium.   Instead,  [4mgrodvi[24m  emits  the equivalent to TeX’s
       [1m\special{papersize=[4m[22mwidth[24m[1m,[4m[22mlength[24m[1m} [22mon the first page; [4mdvips[24m  (or  another
       DVI  driver)  then  sets the page size accordingly.  If either the page
       width or length is not positive, no [1mpapersize [22mspecial is output.

       A device control escape sequence [1m\X'[4m[22manything[24m[1m' [22mis translated to the same
       DVI file instructions as would be  produced  by  [1m\special{[4m[22manything[24m[1m}  [22min
       TeX; [4manything[24m cannot contain a newline.

   [1mTypefaces[0m
       [4mgrodvi[24m  supports  the  standard  four  styles: [1mR [22m(roman), [1mI [22m([4mitalic[24m), [1mB[0m
       ([1mbold[22m), and [1mBI [22m([4m[1mbold‐italic[24m[22m).  Fonts are grouped into families [1mT [22mand  [1mH[0m
       having members in each style.  “CM” abbreviates “Computer Modern”.

              [1mTR     [22mCM Roman (cmr10)
              [1mTI     [22mCM Text Italic (cmti10)
              [1mTB     [22mCM Bold Extended Roman (cmbx10)
              [1mTBI    [22mCM Bold Extended Text Italic (cmbxti10)
              [1mHR     [22mCM Sans Serif (cmss10)
              [1mHI     [22mCM Slanted Sans Serif (cmssi10)
              [1mHB     [22mCM Sans Serif Bold Extended (cmssbx10)
              [1mHBI    [22mCM Slanted Sans Serif Bold Extended (cmssbxo10)

       The following fonts are not members of a family.

              [1mCW     [22mCM Typewriter Text (cmtt10)
              [1mCWI    [22mCM Italic Typewriter Text (cmitt10)

       Special  fonts  include  [1mMI  [22m(cmmi10), [1mS [22m(cmsy10), [1mEX [22m(cmex10), [1mSC [22m(cm‐
       tex10, only for [1mCW[22m), and, perhaps surprisingly, [1mTR[22m, [1mTI[22m, and [1mCW[22m, because
       TeX places some glyphs in text fonts that  [4mtroff[24m  generally  does  not.
       For italic fonts, [1mCWI [22mis used instead of [1mCW[22m.

       Finally,  the  symbol  fonts  of  the American Mathematical Society are
       available as special fonts [1mSA [22m(msam10) and [1mSB [22m(msbm10).  They  are  are
       not mounted by default.

       The  [4mtroff[24m  option  [1m-mec [22mloads the [4mec.tmac[24m macro file, employing the EC
       and TC fonts instead of CM.  These are designed similarly to  the  Com‐
       puter  Modern  fonts;  further,  they  provide Euro [1m\[Eu] [22mand per mille
       [1m\[%0] [22mglyphs.  [4mec.tmac[24m must  be  loaded  before  any  language‐specific
       macro  files  because  it does not set up the codes necessary for auto‐
       matic hyphenation.

   [1mFont description files[0m
       Use [4mtfmtodit[24m(1) to create [4mgroff[24m font description files  from  TFM  (TeX
       font metrics) files.  The font description file should contain the fol‐
       lowing additional directives, which [4mtfmtodit[24m generates automatically.

       [1minternalname [4m[22mname[0m
              The name of the TFM file (without the [4m.tfm[24m extension) is [4mname[24m.

       [1mchecksum [4m[22mn[0m
              The checksum in the TFM file is [4mn[24m.

       [1mdesignsize [4m[22mn[0m
              The design size in the TFM file is [4mn[24m.

   [1mDrawing commands[0m
       [4mgrodvi[24m supports an additional drawing command.

       [1m\D'R [4m[22mdh[24m [4mdv[24m[1m'[0m
              Draw a rule (solid black rectangle) with one corner at the draw‐
              ing  position, and the diagonally opposite corner at the drawing
              position +([4mdh[24m,[4mdv[24m), which becomes the new drawing position after‐
              ward.  This command produces a rule in the DVI file and  so  can
              be  printed  even  with a driver that does not support [4mtpic[24m spe‐
              cials, unlike the other [1m\D [22mcommands.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-d     [22mDo  not  use [4mtpic[24m specials to implement drawing commands.  Hori‐
              zontal and vertical lines are implemented by rules.  Other draw‐
              ing commands are ignored.

       [1m-F [4m[22mdir[24m Prepend directory dir[4m/dev[24mname to the search path  for  font  and
              device  description  files; [4mname[24m is the name of the device, usu‐
              ally [1mdvi[22m.

       [1m-l     [22mUse landscape orientation rather than portrait.

       [1m-p [4m[22mpaper‐format[0m
              Set  physical  dimensions  of  output  medium,  overriding   the
              [1mpapersize[22m,  [1mpaperlength[22m,  and  [1mpaperwidth [22mdirectives in the [4mDESC[0m
              file.   [4mpaper‐format[24m  can  be  any  argument  accepted  by   the
              [1mpapersize [22mdirective; see [4mgroff_font[24m(5).

       [1m-w [4m[22mn[24m   Draw  rules  (lines) with a thickness of [4mn[24m thousandths of an em.
              The default thickness is [1m40 [22m(0.04 em).

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              lists directories in which to search for [4mdevdvi[24m, [4mgrodvi[24m’s direc‐
              tory of device and font description  files.   See  [4mtroff[24m(1)  and
              [4mgroff_font[24m(5).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/DESC[0m
              describes the [1mdvi [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devdvi/[24mF
              describes the font known as [4mF[24m on device [1mdvi[22m.

       [4m/usr/share/groff/1.23.0/tmac/dvi.tmac[0m
              defines  font  mappings,  special characters, and colors for use
              with the [1mdvi [22moutput  device.   It  is  automatically  loaded  by
              [4mtroffrc[24m when the [1mdvi [22moutput device is selected.

       [4m/usr/share/groff/1.23.0/tmac/ec.tmac[0m
              configures the [1mdvi [22moutput device to use the EC and TC font fami‐
              lies instead of CM (Computer Modern).

[1mBugs[0m
       DVI  files  produced by [4mgrodvi[24m use a different resolution (57,816 units
       per inch) from those produced  by  TeX.   Incorrectly  written  drivers
       which  assume the resolution used by TeX, rather than using the resolu‐
       tion specified in the DVI file, will not work with [4mgrodvi[24m.

       When using the [1m-d [22moption with boxed  tables,  vertical  and  horizontal
       lines  can  sometimes  protrude by one pixel.  This is a consequence of
       the way TeX requires that the heights and widths of rules be rounded.

[1mSee also[0m
       “What are the EC fonts?”   ⟨https://texfaq.org/FAQ-ECfonts⟩;  TeX  FAQ:
       Frequently Asked Question List for TeX

       [4mtfmtodit[24m(1),    [4mgroff[24m(1),    [4mtroff[24m(1),   [4mgroff_out[24m(5),   [4mgroff_font[24m(5),
       [4mgroff_char[24m(7), [4mgroff_tmac[24m(5)

groff 1.23.0                      5 July 2023                        [4mgrodvi[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgroff[24m(1)                    General Commands Manual                   [4mgroff[24m(1)

[1mName[0m
       groff - front end to the GNU [4mroff[24m document formatting system

[1mSynopsis[0m
       [1mgroff [22m[[1m-abcCeEgGijklNpRsStUVXzZ[22m] [[1m-d [4m[22mctext[24m] [[1m-d [4m[22mstring[24m[1m=[4m[22mtext[24m]
             [[1m-D [4m[22mfallback‐encoding[24m] [[1m-f [4m[22mfont‐family[24m] [[1m-F [4m[22mfont‐directory[24m]
             [[1m-I [4m[22minclusion‐directory[24m] [[1m-K [4m[22minput‐encoding[24m] [[1m-L [4m[22mspooler‐[0m
             [4margument[24m] [[1m-m [4m[22mmacro‐package[24m] [[1m-M [4m[22mmacro‐directory[24m] [[1m-n [4m[22mpage‐[0m
             [4mnumber[24m] [[1m-o [4m[22mpage‐list[24m] [[1m-P [4m[22mpostprocessor‐argument[24m] [[1m-r [4m[22mcnumeric‐[0m
             [4mexpression[24m] [[1m-r [4m[22mregister[24m[1m=[4m[22mnumeric‐expression[24m] [[1m-T [4m[22moutput‐device[24m]
             [[1m-w [4m[22mwarning‐category[24m] [[1m-W [4m[22mwarning‐category[24m] [[4mfile[24m ...]

       [1mgroff -h[0m
       [1mgroff --help[0m

       [1mgroff -v [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff --version [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       [4mgroff[24m is the primary front end to the GNU [4mroff[24m document formatting sys‐
       tem.  GNU [4mroff[24m is a typesetting system  that  reads  plain  text  input
       files that include formatting commands to produce output in PostScript,
       PDF,  HTML,  DVI, or other formats, or for display to a terminal.  For‐
       matting commands can be low‐level typesetting primitives, macros from a
       supplied package, or user‐defined macros.  All three approaches can  be
       combined.   If no [4mfile[24m operands are specified, or if [4mfile[24m is “[1m-[22m”, [4mgroff[0m
       reads the standard input stream.

       A reimplementation and extension of  the  typesetter  from  AT&T  Unix,
       [4mgroff[24m  is  present  on most POSIX systems owing to its long association
       with Unix manuals (including man pages).  It and  its  predecessor  are
       notable for their production of several best‐selling software engineer‐
       ing texts.  [4mgroff[24m is capable of producing typographically sophisticated
       documents while consuming minimal system resources.

       The  [4mgroff[24m  command  orchestrates  the  execution of preprocessors, the
       transformation of input documents into a  device‐independent  page  de‐
       scription language, and the production of output from that language.

[1mOptions[0m
       [1m-h [22mand [1m--help [22mdisplay a usage message and exit.

       Because  [4mgroff[24m is intended to subsume most users’ direct invocations of
       the [4mtroff[24m(1) formatter, the two programs share a set of options.   How‐
       ever,  [4mgroff[24m  has  some  options  that [4mtroff[24m does not share, and others
       which [4mgroff[24m interprets differently.  At the same time,  not  all  valid
       [4mtroff[24m options can be given to [4mgroff[24m.

   [4m[1mgroff[24m‐specific options[0m
       The  following  options  either do not exist in GNU [4mtroff[24m or are inter‐
       preted differently by [4mgroff[24m.

       [1m-D [4m[22menc[24m Set fallback input encoding used by [4mpreconv[24m(1) to  [4menc[24m;  implies
              [1m-k[22m.

       [1m-e     [22mRun [4meqn[24m(1) preprocessor.

       [1m-g     [22mRun [4mgrn[24m(1) preprocessor.

       [1m-G     [22mRun [4mgrap[24m(1) preprocessor; implies [1m-p[22m.

       [1m-I [4m[22mdir[24m Works as [4mtroff[24m’s option (see below), but also implies [1m-g [22mand [1m-s[22m.
              It  is  passed  to  [4msoelim[24m(1)  and the output driver, and [4mgrn[24m is
              passed an [1m-M [22moption with [4mdir[24m as its argument.

       [1m-j     [22mRun [4mchem[24m(1) preprocessor; implies [1m-p[22m.

       [1m-k     [22mRun [4mpreconv[24m(1) preprocessor.  Refer to its man page for its  be‐
              havior if neither of [4mgroff[24m’s [1m-K [22mor [1m-D [22moptions is also specified.

       [1m-K [4m[22menc[24m Set input encoding used by [4mpreconv[24m(1) to [4menc[24m; implies [1m-k[22m.

       [1m-l     [22mSend  the output to a spooler program for printing.  The “[1mprint[22m”
              directive in the device description file specifies  the  default
              command  to be used; see [4mgroff_font[24m(5).  If no such directive is
              present for the output device, this option is ignored.  See  op‐
              tions [1m-L [22mand [1m-X[22m.

       [1m-L [4m[22marg[24m Pass [4marg[24m to the print spooler program.  If multiple [4marg[24ms are re‐
              quired,  pass  each  with  a separate [1m-L [22moption.  [4mgroff[24m does not
              prefix an option dash to [4marg[24m before passing it  to  the  spooler
              program.

       [1m-M     [22mWorks  as  [4mtroff[24m’s  option  (see  below),  but is also passed to
              [4meqn[24m(1), [4mgrap[24m(1), and [4mgrn[24m(1).

       [1m-N     [22mProhibit newlines between [4meqn[24m delimiters: pass [1m-N [22mto [4meqn[24m(1).

       [1m-p     [22mRun [4mpic[24m(1) preprocessor.

       [1m-P [4m[22marg[24m Pass [4marg[24m to the postprocessor.  If multiple [4marg[24ms  are  required,
              pass  each  with a separate [1m-P [22moption.  [4mgroff[24m does not prefix an
              option dash to [4marg[24m before passing it to the postprocessor.

       [1m-R     [22mRun [4mrefer[24m(1) preprocessor.  No mechanism is provided for passing
              arguments to [4mrefer[24m because most [4mrefer[24m  options  have  equivalent
              language elements that can be specified within the document.

       [1m-s     [22mRun [4msoelim[24m(1) preprocessor.

       [1m-S     [22mOperate in “safer” mode; see [1m-U [22mbelow for its opposite.  For se‐
              curity reasons, safer mode is enabled by default.

       [1m-t     [22mRun [4mtbl[24m(1) preprocessor.

       [1m-T [4m[22mdev[24m Direct  [4mtroff[24m  to  format  the  input for the output device [4mdev[24m.
              [4mgroff[24m then calls an output driver to convert [4mtroff[24m’s output to a
              form appropriate for [4mdev[24m; see subsection “Output devices” below.

       [1m-U     [22mOperate in unsafe mode: pass the [1m-U [22moption to [4mpic[24m and [4mtroff[24m.

       [1m-v[0m
       [1m--version[0m
              Write version information for [4mgroff[24m and all programs run  by  it
              to  the  standard output stream; that is, the given command line
              is processed in the usual way, passing [1m-v [22mto the  formatter  and
              any pre‐ or postprocessors invoked.

       [1m-V     [22mOutput  the pipeline that [4mgroff[24m would run to the standard output
              stream, but do not execute it.  If given more than  once,  [4mgroff[0m
              both writes and runs the pipeline.

       [1m-X     [22mUse [4mgxditview[24m(1) instead of the usual postprocessor to (pre)view
              a  document  on an X11 display.  Combining this option with [1m-Tps[0m
              uses the font metrics of  the  PostScript  device,  whereas  the
              [1m-TX75 [22mand [1m-TX100 [22moptions use the metrics of X11 fonts.

       [1m-Z     [22mDisable  postprocessing.   [4mtroff[24m output will appear on the stan‐
              dard output stream (unless suppressed with [1m-z[22m); see [4mgroff_out[24m(5)
              for a description of this format.

   [1mTransparent options[0m
       The following  options  are  passed  as‐is  to  the  formatter  program
       [4mtroff[24m(1) and described in more detail in its man page.

       [1m-a     [22mGenerate a plain text approximation of the typeset output.

       [1m-b     [22mWrite  a backtrace to the standard error stream on each error or
              warning.

       [1m-c     [22mStart with color output disabled.

       [1m-C     [22mEnable AT&T [4mtroff[24m compatibility mode; implies [1m-c[22m.

       [1m-d [4m[22mcs[0m
       [1m-d [4m[22mname[24m[1m=[4m[22mstring[0m
              Define string.

       [1m-E     [22mInhibit [4mtroff[24m error messages; implies [1m-Ww[22m.

       [1m-f [4m[22mfam[24m Set default font family.

       [1m-F [4m[22mdir[24m Search in directory [4mdir[24m for the selected output device’s  direc‐
              tory of device and font description files.

       [1m-i     [22mProcess standard input after the specified input files.

       [1m-I [4m[22mdir[24m Search [4mdir[24m for input files.

       [1m-m [4m[22mname[0m
              Process name[4m.tmac[24m before input files.

       [1m-M [4m[22mdir[24m Search directory [4mdir[24m for macro files.

       [1m-n [4m[22mnum[24m Number the first page [4mnum[24m.

       [1m-o [4m[22mlist[0m
              Output only pages in [4mlist[24m.

       [1m-r [4m[22mcnumeric‐expression[0m
       [1m-r [4m[22mregister[24m[1m=[4m[22mnumeric‐expression[0m
              Define register.

       [1m-w [4m[22mname[0m
       [1m-W [4m[22mname[0m
              Enable  ([1m-w[22m)  or  inhibit  ([1m-W[22m) emission of warnings in category
              [4mname[24m.

       [1m-z     [22mSuppress formatted device‐independent output of [4mtroff[24m.

[1mUsage[0m
       The architecture of the GNU [4mroff[24m system follows that of  other  device‐
       independent [4mroff[24m implementations, comprising preprocessors, macro pack‐
       ages,  output  drivers (or “postprocessors”), a suite of utilities, and
       the formatter [4mtroff[24m at its heart.  See [4mroff[24m(7) for a survey  of  how  a
       [4mroff[24m system works.

       The  front end programs available in the GNU [4mroff[24m system make it easier
       to use  than  traditional  [4mroff[24ms  that  required  the  construction  of
       pipelines  or  use  of  temporary files to carry a source document from
       maintainable form to device‐ready output.  The discussion below  summa‐
       rizes  the  constituent  parts  of the GNU [4mroff[24m system.  It complements
       [4mroff[24m(7) with [4mgroff[24m‐specific information.

   [1mGetting started[0m
       Those who prefer to learn by experimenting or  are  desirous  of  rapid
       feedback from the system may wish to start with a “Hello, world!” docu‐
       ment.

       $ [1mecho "Hello, world!" | groff -Tascii | sed '/^$/d'[0m
       Hello, world!

       We  used  a [4msed[24m command only to eliminate the 65 blank lines that would
       otherwise flood the terminal screen.  ([4mroff[24m systems were  developed  in
       the days of paper‐based terminals with 66 lines to a page.)

       Today’s users may prefer output to a UTF‐8‐capable terminal.

       $ [1mecho "Hello, world!" | groff -Tutf8 | sed '/^$/d'[0m

       Producing  PDF,  HTML,  or TeX’s DVI is also straightforward.  The hard
       part may be selecting a viewer program for the output.

       $ [1mecho "Hello, world!" | groff -Tpdf > hello.pdf[0m
       $ [1mevince hello.pdf[0m
       $ [1mecho "Hello, world!" | groff -Thtml > hello.html[0m
       $ [1mfirefox hello.html[0m
       $ [1mecho "Hello, world!" | groff -Tdvi > hello.dvi[0m
       $ [1mxdvi hello.html[0m

   [1mUsing [4mgroff[24m as a REPL[0m
       Those with a programmer’s bent may be pleased to know that they can use
       [4mgroff[24m in a read‐evaluate‐print loop (REPL).  Doing so can be  handy  to
       verify  one’s understanding of the formatter’s behavior and/or the syn‐
       tax it accepts.  Turning on all warnings with [1m-ww [22mcan aid this goal.

       $ [1mgroff -ww -Tutf8[0m
       [1m\# This is a comment. Let's define a register.[0m
       [1m.nr a 1[0m
       [1m\# Do integer arithmetic with operators evaluated left‐to‐right.[0m
       [1m.nr b \n[a]+5/2[0m
       [1m\# Let's get the result on the standard error stream.[0m
       [1m.tm \n[b][0m
       3
       [1m\# Now we'll define a string.[0m
       [1m.ds name Leslie\" This is another form of comment.[0m
       [1m.nr b (\n[a] + (7/2))[0m
       [1m\# Center the next two text input lines.[0m
       [1m.ce 2[0m
       [1mHi, \*[name].[0m
       [1mYour secret number is \n[b].[0m
       [1m\# We will see that the division rounded toward zero.[0m
       [1mIt is[0m
       [1m\# Here's an if‐else control structure.[0m
       [1m.ie (\n[b] % 2) odd.[0m
       [1m.el even.[0m
       [1m\# This trick sets the page length to the current vertical[0m
       [1m\# position, so that blank lines don't spew when we're done.[0m
       [1m.pl \n[nl]u[0m
       [4m<Control‐D>[0m
                                  Hi, Leslie.
                           Your secret number is 4.
       It is even.

   [1mPaper format[0m
       In GNU [4mroff[24m, the page dimensions for the formatter [4mtroff[24m and for output
       devices are handled separately.  In the formatter, requests are used to
       set the page length ([1m.pl[22m), page offset (or left margin, [1m.po[22m), and  line
       length  ([1m.ll[22m).  The right margin is not explicitly configured; the com‐
       bination of page offset and line length provides the information neces‐
       sary to derive it.  The [4mpapersize[24m macro package,  automatically  loaded
       by [4mtroff[24m, provides an interface for configuring page dimensions by con‐
       venient  names,  like “letter” or “A4”; see [4mgroff_tmac[24m(5).  The format‐
       ter’s default in this installation is “[1mA4[22m”.

       It is up to each macro package to respect the page  dimensions  config‐
       ured in this way.  Some offer alternative mechanisms.

       For each output device, the size of the output medium can be set in its
       [4mDESC[24m file.  Most output drivers also recognize a command‐line option [1m-p[0m
       to  override  the  default dimensions and an option [1m-l [22mto use landscape
       orientation.  See [4mgroff_font[24m(5) for a description of the [1mpapersize  [22mdi‐
       rective,  which  takes  an argument of the same form as [1m-p[22m.  The output
       driver’s man page, such as [4mgrops[24m(1), may also be helpful.   [4mgroff[24m  uses
       the command‐line option [1m-P [22mto pass options to output devices; for exam‐
       ple,  use  the following for PostScript output on A4 paper in landscape
       orientation.

              groff -Tps -dpaper=a4l -P-pa4 -P-l -ms foo.ms > foo.ps

   [1mFront end[0m
       The [4mgroff[24m program is a wrapper around the [4mtroff[24m(1) program.  It  allows
       one to specify preprocessors via command‐line options and automatically
       runs the appropriate postprocessor for the selected output device.  Do‐
       ing so, the manual construction of pipelines or management of temporary
       files  required of users of traditional [4mroff[24m(7) systems can be avoided.
       Use the [4mgrog[24m(1) program to infer an appropriate [4mgroff[24m command  line  to
       format a document.

   [1mLanguage[0m
       Input  to a [4mroff[24m system is in plain text interleaved with control lines
       and escape sequences.  The combination constitutes a document in one of
       a family of languages we also call [4mroff[24m; see  [4mroff[24m(7)  for  background.
       An  overview  of GNU [4mroff[24m language syntax and features, including lists
       of all supported escape sequences, requests, and predefined  registers,
       can  be  found in [4mgroff[24m(7).  GNU [4mroff[24m extensions to the AT&T [4mtroff[24m lan‐
       guage, a common subset of [4mroff[24m dialects extant today, are  detailed  in
       [4mgroff_diff[24m(7).

   [1mPreprocessors[0m
       A preprocessor interprets a domain‐specific language that produces [4mroff[0m
       language output.  Frequently, such input is confined to sections or re‐
       gions of a [4mroff[24m input file (bracketed with macro calls specific to each
       preprocessor), which it replaces.  Preprocessors therefore often inter‐
       pret  a  subset of [4mroff[24m syntax along with their own language.  GNU [4mroff[0m
       provides reimplementations of most preprocessors familiar to  users  of
       AT&T  [4mtroff[24m;  these routinely have extended features and/or require GNU
       [4mtroff[24m to format their output.

              [4mtbl[24m         lays out tables;
              [4meqn[24m         typesets mathematics;
              [4mpic[24m         draws diagrams;
              [4mrefer[24m       processes bibliographic references;
              [4msoelim[24m      preprocesses “sourced” input files;
              [4mgrn[24m         renders [4mgremlin[24m(1) diagrams;
              [4mchem[24m        draws chemical structural formulæ using [4mpic[24m;
              [4mgperl[24m       populates [4mgroff[24m registers and strings using [4mperl[24m(1);
              [4mglilypond[24m   embeds [4mLilyPond[24m sheet music; and
              [4mgpinyin[24m     eases Mandarin Chinese input using Hanyu Pinyin.

       A preprocessor unique to GNU [4mroff[24m is [4mpreconv[24m(1), which converts various
       input encodings to something GNU [4mtroff[24m can understand.  When  used,  it
       is run before any other preprocessors.

       Most preprocessors enclose content between a pair of characteristic to‐
       kens.   Such  a  token must occur at the beginning of an input line and
       use the dot control character.  Spaces and tabs  must  not  follow  the
       control character or precede the end of the input line.  Deviating from
       these  rules defeats a token’s recognition by the preprocessor.  Tokens
       are generally preserved in preprocessor output and interpreted as macro
       calls subsequently by [4mtroff[24m.  The [4mideal[24m preprocessor is not yet  avail‐
       able in [4mgroff[24m.

                ┌──────────────┬─────────────────┬────────────────┐
                │ preprocessor │ starting token  │  ending token  │
                ├──────────────┼─────────────────┼────────────────┤
                │     chem     │     .cstart     │     .cend      │
                │     eqn      │       .EQ       │      .EN       │
                │     grap     │       .G1       │      .G2       │
                │     grn      │       .GS       │      .GE       │
                │    ideal     │       .IS       │      .IE       │
                │              │                 │      .IF       │
                │     pic      │       .PS       │      .PE       │
                │              │                 │      .PF       │
                │              │                 │      .PY       │
                │    refer     │       .R1       │      .R2       │
                │     tbl      │       .TS       │      .TE       │
                ├──────────────┼─────────────────┼────────────────┤
                │  glilypond   │ .lilypond start │ .lilypond stop │
                │    gperl     │   .Perl start   │   .Perl stop   │
                │   gpinyin    │  .pinyin start  │  .pinyin stop  │
                └──────────────┴─────────────────┴────────────────┘

   [1mMacro packages[0m
       Macro  files  are  [4mroff[24m input files designed to produce no output them‐
       selves but instead ease the preparation of other [4mroff[24m documents.   When
       a  macro  file is installed at a standard location and suitable for use
       by a general audience, it is termed a [4mmacro[24m [4mpackage[24m.

       Macro packages can be loaded prior to any [4mroff[24m input documents with the
       [1m-m [22moption.  The GNU [4mroff[24m system implements most well‐known macro  pack‐
       ages  for  AT&T [4mtroff[24m in a compatible way and extends them.  These have
       one‐ or two‐letter names arising from intense practices of naming econ‐
       omy in early Unix culture, a laconic approach that led to many  of  the
       packages being identified in general usage with the [4mnroff[24m and [4mtroff[24m op‐
       tion  letter  used to invoke them, sometimes to punning effect, as with
       “man” (short for “manual”), and even with the option dash,  as  in  the
       case of the [4ms[24m package, much better known as [4mms[24m or even [4m-ms[24m.

       Macro  packages  serve  a variety of purposes.  Some are “full‐service”
       packages, adopting responsibility for page layout among other fundamen‐
       tal tasks, and defining their own lexicon of macros for document compo‐
       sition; each such package stands alone and a given document can use  at
       most one.

       [4man[24m     is  used  to compose man pages in the format originating in Ver‐
              sion 7 Unix (1979); see [4mgroff_man[24m(7).  It can  be  specified  on
              the command line as [1m-man[22m.

       [4mdoc[24m    is  used  to  compose  man  pages  in  the format originating in
              4.3BSD‐Reno (1990); see [4mgroff_mdoc[24m(7).  It can be  specified  on
              the command line as [1m-mdoc[22m.

       [4me[24m      is the Berkeley general‐purpose macro suite, developed as an al‐
              ternative  to AT&T’s [4ms[24m; see [4mgroff_me[24m(7).  It can be specified on
              the command line as [1m-me[22m.

       [4mm[24m      implements the format used by the second‐generation  AT&T  macro
              suite  for general documents, a successor to [4ms[24m; see [4mgroff_mm[24m(7).
              It can be specified on the command line as [1m-mm[22m.

       [4mom[24m     (invariably called “mom”) is a modern package written  by  Peter
              Schaffter  specifically for GNU [4mroff[24m.  Consult the [4mmom[24m HTML man‐
              ual  ⟨file:///usr/share/doc/groff-1.23.0/html/mom/toc.html⟩  for
              extensive  documentation.  She—for [4mmom[24m takes the female pronoun—
              can be specified on the command line as [1m-mom[22m.

       [4ms[24m      is  the  original  AT&T  general‐purpose  document  format;  see
              [4mgroff_ms[24m(7).  It can be specified on the command line as [1m-ms[22m.

       Others are supplemental.  For instance, [4mandoc[24m is a wrapper package spe‐
       cific  to  GNU [4mroff[24m that recognizes whether a document uses [4mman[24m or [4mmdoc[0m
       format and loads the corresponding macro package.  It can be  specified
       on  the  command  line  as [1m-mandoc[22m.  A [4mman[24m(1) librarian program may use
       this macro file to delegate loading of the correct macro package; it is
       thus unnecessary for [4mman[24m itself to scan the contents of a  document  to
       decide the issue.

       Many  macro files augment the function of the full‐service packages, or
       of [4mroff[24m documents that do not employ  such  a  package—the  latter  are
       sometimes  characterized  as  “raw”.   These auxiliary packages are de‐
       scribed, along with details of macro  file  naming  and  placement,  in
       [4mgroff_tmac[24m(5).

   [1mFormatters[0m
       The  formatter,  the  program  that  interprets [4mroff[24m language input, is
       [4mtroff[24m(1).  It provides the features of the AT&T [4mtroff[24m  and  [4mnroff[24m  pro‐
       grams  as well as many extensions.  The command‐line option [1m-C [22mswitches
       [4mtroff[24m into [4mcompatibility[24m [4mmode[24m, which tries to  emulate  AT&T  [4mtroff[24m  as
       closely  as  is practical to enable the formatting of documents written
       for the older system.

       A shell script, [4mnroff[24m(1), emulates the behavior of AT&T [4mnroff[24m.  It  at‐
       tempts  to  correctly  encode the output based on the locale, relieving
       the user of the need to specify an output device with the [1m-T [22moption and
       is therefore convenient for use with terminal output devices, described
       in the next subsection.

       GNU [4mtroff[24m generates output in a device‐independent, but not  device‐ag‐
       nostic, page description language detailed in [4mgroff_out[24m(5).

   [1mOutput devices[0m
       [4mtroff[24m  output  is  formatted  for a particular [4moutput[24m [4mdevice[24m, typically
       specified by the [1m-T [22moption to the formatter or a front end.  If neither
       this option nor the [4mGROFF_TYPESETTER[24m environment variable is used,  the
       default  output  device is [1mps[22m.  An output device may be any of the fol‐
       lowing.

       [1mascii    [22mfor terminals using the ISO 646 1991:IRV character set and en‐
                coding, also known as US‐ASCII.

       [1mcp1047   [22mfor terminals using the IBM code page 1047 character  set  and
                encoding.

       [1mdvi      [22mfor TeX DVI format.

       [1mhtml[0m
       [1mxhtml    [22mfor HTML and XHTML output, respectively.

       [1mlatin1   [22mfor terminals using the ISO Latin‐1 (ISO 8859‐1) character set
                and encoding.

       [1mlbp      [22mfor  Canon CaPSL printers (LBP‐4 and LBP‐8 series laser print‐
                ers).

       [1mlj4      [22mfor HP LaserJet4‐compatible (or other PCL5‐compatible)  print‐
                ers.

       [1mpdf      [22mfor PDF output.

       [1mps       [22mfor PostScript output.

       [1mutf8     [22mfor terminals using the ISO 10646 (“Unicode”) character set in
                UTF‐8 encoding.

       [1mX75      [22mfor  previewing  with  [4mgxditview[24m using 75 dpi resolution and a
                10‐point base type size.

       [1mX75-12   [22mfor previewing with [4mgxditview[24m using 75 dpi  resolution  and  a
                12‐point base type size.

       [1mX100     [22mfor  previewing  with [4mgxditview[24m using 100 dpi resolution and a
                10‐point base type size.

       [1mX100-12  [22mfor previewing with [4mgxditview[24m using 100 dpi resolution  and  a
                12‐point base type size.

   [1mPostprocessors[0m
       Any program that interprets the output of GNU [4mtroff[24m is a postprocessor.
       The  postprocessors provided by GNU [4mroff[24m are [4moutput[24m [4mdrivers[24m, which pre‐
       pare a document for viewing or printing.  Postprocessors for other pur‐
       poses, such as page resequencing or statistical measurement of a  docu‐
       ment, are conceivable.

       An output driver supports one or more output devices, each with its own
       device  description  file.   A device determines its postprocessor with
       the  [1mpostpro  [22mdirective   in   its   device   description   file;   see
       [4mgroff_font[24m(5).    The  [1m-X  [22moption  overrides  this  selection,  causing
       [4mgxditview[24m to serve as the output driver.

       [4mgrodvi[24m(1)
              provides [1mdvi[22m.

       [4mgrohtml[24m(1)
              provides [1mhtml [22mand [1mxhtml[22m.

       [4mgrolbp[24m(1)
              provides [1mlbp[22m.

       [4mgrolj4[24m(1)
              provides [1mlj4[22m.

       [4mgropdf[24m(1)
              provides [1mpdf[22m.

       [4mgrops[24m(1)
              provides [1mps[22m.

       [4mgrotty[24m(1)
              provides [1mascii[22m, [1mcp1047[22m, [1mlatin1[22m, and [1mutf8[22m.

       [4mgxditview[24m(1)
              provides [1mX75[22m, [1mX75-12[22m, [1mX100[22m, and [1mX100-12[22m,  and  additionally  can
              preview [1mps[22m.

   [1mUtilities[0m
       GNU [4mroff[24m includes a suite of utilities.

       [4mgdiffmk[24m(1)
              marks differences between a pair of [4mroff[24m input files.

       [4mgrog[24m(1)
              infers the [4mgroff[24m command a document requires.

       Several utilities prepare descriptions of fonts, enabling the formatter
       to use them when producing output for a given device.

       [4maddftinfo[24m(1)
              adds  information to AT&T [4mtroff[24m font description files to enable
              their use with GNU [4mtroff[24m.

       [4mafmtodit[24m(1)
              creates font description files for PostScript Type 1 fonts.

       [4mpfbtops[24m(1)
              translates a PostScript Type 1 font in PFB (Printer Font Binary)
              format to PFA (Printer Font ASCII), which  can  then  be  inter‐
              preted by [4mafmtodit[24m.

       [4mhpftodit[24m(1)
              creates  font  description files for the HP LaserJet 4 family of
              printers.

       [4mtfmtodit[24m(1)
              creates font description files for the TeX DVI device.

       [4mxtotroff[24m(1)
              creates font description files for X Window System core fonts.

       A trio of tools transform material constructed using [4mroff[24m  preprocessor
       languages into graphical image files.

       [4meqn2graph[24m(1)
              converts an [4meqn[24m equation into a cropped image.

       [4mgrap2graph[24m(1)
              converts a [4mgrap[24m diagram into a cropped image.

       [4mpic2graph[24m(1)
              converts a [4mpic[24m diagram into a cropped image.

       Another set of programs works with the bibliographic data files used by
       the [4mrefer[24m(1) preprocessor.

       [4mindxbib[24m(1)
              makes  inverted  indices  for  bibliographic databases, speeding
              lookup operations on them.

       [4mlkbib[24m(1)
              searches the databases.

       [4mlookbib[24m(1)
              interactively searches the databases.

[1mExit status[0m
       [4mgroff[24m exits with a failure status if there was a  problem  parsing  its
       arguments and a successful status if either of the options [1m-h [22mor [1m--help[0m
       was  specified.  Otherwise, [4mgroff[24m runs a pipeline to process its input;
       if all commands within the pipeline exit successfully, [4mgroff[24m does like‐
       wise.  If not, [4mgroff[24m’s exit status encodes a summary  of  problems  en‐
       countered,  setting  bit  0  if a command exited with a failure status,
       bit 1 if a command was terminated with a signal, and bit 2 if a command
       could not be executed.  (Thus, if all three  misfortunes  befell  one’s
       pipeline,  [4mgroff[24m  would  exit with status 2^0 + 2^1 + 2^2 = 1+2+4 = 7.)
       To troubleshoot pipeline problems, you may wish  to  re‐run  the  [4mgroff[0m
       command  with  the  [1m-V [22moption and break the reported pipeline down into
       separate stages, inspecting the exit status of and diagnostic  messages
       emitted by each command.

[1mEnvironment[0m
       Normally,  the path separator in environment variables ending with [4mPATH[0m
       is the colon; this may vary depending on the operating system.  For ex‐
       ample, Windows uses a semicolon instead.

       [4mGROFF_BIN_PATH[0m
              This search path, followed by [4mPATH[24m, is used to  locate  commands
              executed by [4mgroff[24m.  If it is not set, the installation directory
              of the GNU [4mroff[24m executables, [4m/usr/bin[24m, is searched before [4mPATH[24m.

       [4mGROFF_COMMAND_PREFIX[0m
              GNU  [4mroff[24m can be configured at compile time to apply a prefix to
              the names of the programs it provides that had a counterpart  in
              AT&T  [4mtroff[24m,  so  that  name collisions are avoided at run time.
              The default prefix is empty.

              When used, this prefix is conventionally the  letter  “g”.   For
              example, GNU [4mtroff[24m would be installed as [4mgtroff[24m.  Besides [4mtroff[24m,
              the  prefix  applies  to  the formatter [4mnroff[24m; the preprocessors
              [4meqn[24m, [4mgrn[24m, [4mpic[24m, [4mrefer[24m, [4mtbl[24m, and [4msoelim[24m; and the utilities [4mindxbib[0m
              and [4mlookbib[24m.

       [4mGROFF_ENCODING[0m
              The value of this variable is  passed  to  the  [4mpreconv[24m(1)  pre‐
              processor’s  [1m-e [22moption to select the character encoding of input
              files.  This variable’s existence implies the [4mgroff[24m  option  [1m-k[22m.
              If  set  but  empty,  [4mgroff[24m  calls [4mpreconv[24m without an [1m-e [22moption.
              [4mgroff[24m’s [1m-K [22moption overrides [4mGROFF_ENCODING[24m.

       [4mGROFF_FONT_PATH[0m
              Seek the selected output device’s directory of device  and  font
              description files in this list of directories.  See [4mtroff[24m(1) and
              [4mgroff_font[24m(5).

       [4mGROFF_TMAC_PATH[0m
              Seek  macro files in this list of directories.  See [4mtroff[24m(1) and
              [4mgroff_tmac[24m(5).

       [4mGROFF_TMPDIR[0m
              Create temporary files in this directory.  If not set,  but  the
              environment  variable [4mTMPDIR[24m is set, temporary files are created
              there instead.  On Windows systems, if neither of the  foregoing
              are  set, the environment variables [4mTMP[24m and [4mTEMP[24m (in that order)
              are checked also.  Otherwise, temporary  files  are  created  in
              [4m/tmp[24m.   The [4mrefer[24m(1), [4mgrohtml[24m(1), and [4mgrops[24m(1) commands use tem‐
              porary files.

       [4mGROFF_TYPESETTER[0m
              Set the default output device.  If empty or not set, [1mps [22mis used.
              The [1m-T [22moption overrides [4mGROFF_TYPESETTER[24m.

       [4mSOURCE_DATE_EPOCH[0m
              A time stamp (expressed as seconds since the Unix epoch) to  use
              as  the output creation time stamp in place of the current time.
              The time is converted to human‐readable form using  [4mlocaltime[24m(3)
              when  the  formatter starts up and stored in registers usable by
              documents and macro packages.

       [4mTZ[24m     The time zone to use when converting the current time (or  value
              of [4mSOURCE_DATE_EPOCH[24m) to human‐readable form; see [4mtzset[24m(3).

[1mExamples[0m
       [4mroff[24m  systems  are  best known for formatting man pages.  Once a [4mman[24m(1)
       librarian program has located a man page, it may execute a  [4mgroff[24m  com‐
       mand much like the following.
              groff -t -man -Tutf8 /usr/share/man/man1/groff.1
       The  librarian  will  also pipe the output through a pager, which might
       not interpret the SGR terminal escape sequences [4mgroff[24m emits  for  bold‐
       face, underlining, or italics; see section “Limitations” below.

       To  process  a  [4mroff[24m input file using the preprocessors [4mtbl[24m and [4mpic[24m and
       the [4mme[24m macro package in the way to which AT&T [4mtroff[24m users  were  accus‐
       tomed, one would type (or script) a pipeline.

              pic foo.me | tbl | troff -me -Tutf8 | grotty

       Using [4mgroff[24m, this pipe can be shortened to an equivalent command.

              groff -p -t -me -T utf8 foo.me

       An even easier way to do this is to use [4mgrog[24m(1) to guess the preproces‐
       sor  and macro options and execute the result by using the command sub‐
       stitution feature of the shell.

              $(grog -Tutf8 foo.me)

       Each command‐line option to a postprocessor must be specified with  any
       required leading dashes “[1m-[22m” because [4mgroff[24m passes the arguments as‐is to
       the  postprocessor; this permits arbitrary arguments to be transmitted.
       For example, to pass a title to the [4mgxditview[24m postprocessor, the  shell
       commands
              groff -X -P -title -P 'trial run' mydoc.t
       and
              groff -X -Z mydoc.t | gxditview -title 'trial run' -
       are equivalent.

[1mLimitations[0m
       When  paging  output  for  the [1mascii[22m, [1mcp1047[22m, [1mlatin1[22m, and [1mutf8 [22mdevices,
       programs like [4mmore[24m(1) and [4mless[24m(1) may require command‐line  options  to
       correctly handle some terminal escape sequences; see [4mgrotty[24m(1).

       On  EBCDIC  hosts  such  as  OS/390  Unix, the output devices [1mascii [22mand
       [1mlatin1 [22maren’t available.  Conversely, the output device [1mcp1047  [22mis  not
       available  on systems based on the ISO 646 or ISO 8859 character encod‐
       ing standards.

[1mInstallation directories[0m
       GNU [4mroff[24m installs files in varying locations depending on its  compile‐
       time  configuration.  On this installation, the following locations are
       used.

       [4m/usr/bin[0m
              Directory containing [4mgroff[24m’s executable commands.

       [4m/usr/share/groff/1.23.0/eign[0m
              List of common words for [4mindxbib[24m(1).

       [4m/usr/share/groff/1.23.0[0m
              Directory for data files.

       [4m/usr/dict/papers/Ind[0m
              Default index for [4mlkbib[24m(1) and [4mrefer[24m(1).

       [4m/usr/share/doc/groff-1.23.0[0m
              Documentation directory.

       [4m/usr/share/doc/groff-1.23.0/examples[0m
              Example directory.

       [4m/usr/share/groff/1.23.0/font[0m
              Font directory.

       [4m/usr/share/doc/groff-1.23.0/html[0m
              HTML documentation directory.

       [4m/usr/lib/font[0m
              Legacy font directory.

       [4m/usr/share/groff/site-font[0m
              Local font directory.

       [4m/usr/share/groff/site-tmac[0m
              Local macro package ([4mtmac[24m file) directory.

       [4m/usr/share/groff/1.23.0/tmac[0m
              Macro package ([4mtmac[24m file) directory.

       [4m/usr/share/groff/1.23.0/oldfont[0m
              Font directory for compatibility with old versions of [4mgroff[24m; see
              [4mgrops[24m(1).

       [4m/usr/share/doc/groff-1.23.0/pdf[0m
              PDF documentation directory.

   [4m[1mgroff[24m macro directory[0m
       Most macro files supplied with GNU [4mroff[24m are stored in [4m/usr/share/groff/[0m
       [4m1.23.0/tmac[24m for the installation corresponding to this document.  As  a
       rule,  multiple directories are searched for macro files; see [4mtroff[24m(1).
       For a catalog of macro files GNU [4mroff[24m provides, see [4mgroff_tmac[24m(5).

   [4m[1mgroff[24m device and font description directory[0m
       Device and font description files supplied with GNU [4mroff[24m are stored  in
       [4m/usr/share/groff/1.23.0/font[24m for the installation corresponding to this
       document.   As a rule, multiple directories are searched for device and
       font description files; see [4mtroff[24m(1).  For the formats of these  files,
       see [4mgroff_font[24m(5).

[1mAvailability[0m
       Obtain  links  to  [4mgroff[24m  releases for download, its source repository,
       discussion mailing lists, a support ticket tracker, and further  infor‐
       mation  from  the  [4mgroff[24m  page  of the GNU website ⟨http://www.gnu.org/
       software/groff⟩.

       A free implementation of the [4mgrap[24m preprocessor, written  by  Ted  Faber
       ⟨faber@lunabase.org⟩,  can  be  found  at  the [4mgrap[24m website ⟨http://www
       .lunabase.org/~faber/Vault/software/grap/⟩.  [4mgroff[24m supports  only  this
       [4mgrap[24m.

[1mAuthors[0m
       [4mgroff[24m (both the front‐end command and the overall system) was primarily
       written by James Clark ⟨jjc@jclark.com⟩.  Contributors to this document
       include  Clark,  Trent  A.  Fisher,  Werner Lemberg ⟨wl@gnu.org⟩, Bernd
       Warken  ⟨groff-bernd.warken-72@web.de⟩,   and   G.   Branden   Robinson
       ⟨g.branden.robinson@gmail.com⟩.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       Introduction, history, and further reading:
              [4mroff[24m(7)

       Viewer for [4mgroff[24m (and AT&T device‐independent [4mtroff[24m) documents:
              [4mgxditview[24m(1)

       Preprocessors:
              [4mchem[24m(1),  [4meqn[24m(1),  [4mneqn[24m(1),  [4mglilypond[24m(1),  [4mgrn[24m(1),  [4mpreconv[24m(1),
              [4mgperl[24m(1), [4mpic[24m(1), [4mgpinyin[24m(1), [4mrefer[24m(1), [4msoelim[24m(1), [4mtbl[24m(1)

       Macro packages and package‐specific utilities:
              [4mgroff_hdtbl[24m(7), [4mgroff_man[24m(7), [4mgroff_man_style[24m(7), [4mgroff_mdoc[24m(7),
              [4mgroff_me[24m(7),     [4mgroff_mm[24m(7),     [4mgroff_mmse[24m(7),      [4mmmroff[24m(1),
              [4mgroff_mom[24m(7),    [4mpdfmom[24m(1),    [4mgroff_ms[24m(7),    [4mgroff_rfc1345[24m(7),
              [4mgroff_trace[24m(7), [4mgroff_www[24m(7)

       Bibliographic database management tools:
              [4mindxbib[24m(1), [4mlkbib[24m(1), [4mlookbib[24m(1)

       Language, conventions, and GNU extensions:
              [4mgroff[24m(7),    [4mgroff_char[24m(7),    [4mgroff_diff[24m(7),     [4mgroff_font[24m(5),
              [4mgroff_tmac[24m(5)

       Intermediate output language:
              [4mgroff_out[24m(5)

       Formatter program:
              [4mtroff[24m(1)

       Formatter wrappers:
              [4mnroff[24m(1), [4mpdfroff[24m(1)

       Postprocessors for output devices:
              [4mgrodvi[24m(1),    [4mgrohtml[24m(1),   [4mgrolbp[24m(1),   [4mgrolj4[24m(1),   [4mgropdf[24m(1),
              [4mgrops[24m(1), [4mgrotty[24m(1)

       Font support utilities:
              [4maddftinfo[24m(1), [4mafmtodit[24m(1), [4mhpftodit[24m(1), [4mpfbtops[24m(1), [4mtfmtodit[24m(1),
              [4mxtotroff[24m(1)

       Graphics conversion utilities:
              [4meqn2graph[24m(1), [4mgrap2graph[24m(1), [4mpic2graph[24m(1)

       Difference‐marking utility:
              [4mgdiffmk[24m(1)

       “groff guess” utility:
              [4mgrog[24m(1)

groff 1.23.0                      5 July 2023                         [4mgroff[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrog[24m(1)                     General Commands Manual                    [4mgrog[24m(1)

[1mName[0m
       grog - “groff guess”—infer the [4mgroff[24m command a document requires

[1mSynopsis[0m
       [1mgrog [22m[[1m--run[22m] [[1m--ligatures[22m] [[4mgroff‐option[24m ...] [[1m--[22m] [[4mfile[24m ...]

       [1mgrog -h[0m
       [1mgrog --help[0m

       [1mgrog -v[0m
       [1mgrog --version[0m

[1mDescription[0m
       [4mgrog[24m reads its input and guesses which [4mgroff[24m(1) options are  needed  to
       render it.  If no operands are given, or if [4mfile[24m is “[1m-[22m”, [4mgrog[24m reads the
       standard  input  stream.   The  corresponding [4mgroff[24m command is normally
       written to the standard output stream.  With the option [1m--run[22m, the  in‐
       ferred  command  is  written to the standard error stream and then exe‐
       cuted.

[1mOptions[0m
       [1m-h [22mand [1m--help [22mdisplay a usage message, whereas [1m-v [22mand [1m--version [22mdisplay
       version information; all exit afterward.

       [1m--ligatures[0m
              includes the arguments [1m-P-y -PU [22min the inferred  [4mgroff[24m  command.
              These are supported only by the [1mpdf [22moutput device.

       [1m--run  [22mwrites  the  inferred  command  to the standard error stream and
              then executes it.

       All other specified short options (that is, arguments beginning with  a
       minus  sign  “[1m-[22m” followed by a letter) are interpreted as [4mgroff[24m options
       or option clusters with or without an option  argument.   Such  options
       are included in the constructed [4mgroff[24m command line.

[1mDetails[0m
       [4mgrog[24m reads each [4mfile[24m operand, pattern‐matching strings that are statis‐
       tically  likely to be characteristic of [4mroff[24m(7) documents.  It tries to
       guess which of the following [4mgroff[24m options are  required  to  correctly
       render the input: [1m-e[22m, [1m-g[22m, [1m-G[22m, [1m-j[22m, [1m-p[22m, [1m-R[22m, [1m-t [22m(preprocessors); and [1m-man[22m,
       [1m-mdoc[22m,  [1m-mdoc-old[22m,  [1m-me[22m,  [1m-mm[22m, [1m-mom[22m, and [1m-ms [22m(macro packages).  The in‐
       ferred [4mgroff[24m command including these options and any [4mfile[24m parameters is
       written to the standard output stream.

       It is possible to specify arbitrary [4mgroff[24m options on the command  line.
       These  are included in the inferred command without change.  Choices of
       [4mgroff[24m options include [1m-C [22mto enable AT&T [4mtroff[24m compatibility mode and [1m-T[0m
       to select a non‐default output device.  If the input is not encoded  in
       US‐ASCII,  ISO  8859‐1, or IBM code page 1047, specification of a [4mgroff[0m
       option to run the [4mpreconv[24m(1) preprocessor is advised; see the  [1m-D[22m,  [1m-k[22m,
       and [1m-K [22moptions of [4mgroff[24m(1).  For UTF‐8 input, [1m-k [22mis a good choice.

       [4mgroff[24m may issue diagnostic messages when an inappropriate [1m-m [22moption, or
       multiple  conflicting ones, are specified.  Consequently, it is best to
       specify no [1m-m [22moptions to [4mgrog[24m unless it cannot correctly infer  all  of
       the  [1m-m  [22marguments  a  document  requires.  A [4mroff[24m document can also be
       written without recourse to any macro package.   In  such  cases,  [4mgrog[0m
       will infer a [4mgroff[24m command without an [1m-m [22moption.

   [1mLimitations[0m
       [4mgrog[24m  presumes  that  the input does not change the escape, control, or
       no‐break control characters.  [4mgrog[24m does not parse [4mroff[24m input line  con‐
       tinuation  or  control structures (brace escape sequences and the “[1mif[22m”,
       “[1mie[22m”, and “[1mel[22m” requests) nor [4mgroff[24m’s “[1mwhile[22m”.  Thus the input
              .if \
              t .NH 1
              .if n .SH
              Introduction
       will conceal the use of the [4mms[24m macros [1mNH [22mand [1mSH [22mfrom [4mgrog[24m.   Such  con‐
       structions are regarded by [4mgrog[24m’s implementors as insufficiently common
       to  cause  many inference problems.  Preprocessors can be even stricter
       when matching macro calls that bracket the regions  of  an  input  file
       they replace.  [4mpic[24m, for example, requires [1mPS[22m, [1mPE[22m, and [1mPF [22mcalls to imme‐
       diately  follow  the  default  control  character at the beginning of a
       line.

       Detection of the [1m-s [22moption (the [4msoelim[24m(1) preprocessor) is  tricky;  to
       correctly  infer  its  necessity would require [4mgrog[24m to recursively open
       all files given as arguments to the [1m.so [22mrequest under the  same  condi‐
       tions that [4msoelim[24m itself does so; see its man page.  Recall that [4msoelim[0m
       is necessary only if sourced files need to be preprocessed.  Therefore,
       as a workaround, you may want to run the input through [4msoelim[24m manually,
       piping  it to [4mgrog[24m, and compare the output to running [4mgrog[24m on the input
       directly.  If the “[4msoelim[24m”ed input causes [4mgrog[24m to infer additional pre‐
       processor options, then [1m-s [22mis likely necessary.

              $ [1mprintf ".TS\nl.\nI'm a table.\n.TE\n" > 3.roff[0m
              $ [1mprintf ".so 3.roff\n" > 2.roff[0m
              $ [1mprintf ".XP\n.so 2.roff\n" > 1.roff[0m
              $ [1mgrog 1.roff[0m
              groff -ms 1.roff
              $ [1msoelim 1.roff | grog[0m
              groff -t -ms -

       In the foregoing example, we see that this procedure  enabled  [4mgrog[24m  to
       detect [4mtbl[24m(1) macros, so we would add [1m-s [22mas well as the detected [1m-t [22mop‐
       tion to a revised [4mgrog[24m or [4mgroff[24m command.

              $ [1mgrog -st 1.roff[0m
              groff -st -ms 1.roff

[1mExit status[0m
       [4mgrog[24m  exits with error status [1m1 [22mif a macro package appears to be in use
       by the input document, but [4mgrog[24m was unable to infer which one, or [1m2  [22mif
       there  were problems handling an option or operand.  It otherwise exits
       with status [1m0[22m.  (If the [1m--run [22moption is specified, [4mgroff[24m’s exit  status
       is  discarded.)  Inferring no preprocessors or macro packages is not an
       error condition; a valid [4mroff[24m document need not use either.  Even plain
       text is valid input, if one is mindful of the syntax of the control and
       escape characters.

[1mExamples[0m
       Running
              [1mgrog /usr/share/doc/groff-1.23.0/meintro.me[0m
       at the command line results in
              groff -me /usr/share/doc/groff-1.23.0/meintro.me
       because [4mgrog[24m recognizes that  the  file  [4mmeintro.me[24m  is  written  using
       macros from the [4mme[24m package.  The command
              [1mgrog /usr/share/doc/groff-1.23.0/pic.ms[0m
       outputs
              groff -e -p -t -ms /usr/share/doc/groff-1.23.0/pic.ms
       on  the other hand.  Besides discerning the [4mms[24m macro package, [4mgrog[24m rec‐
       ognizes that the file [4mpic.ms[24m additionally needs the combination  of  [1m-t[0m
       for [4mtbl[24m, [1m-e [22mfor [4meqn[24m, and [1m-p [22mfor [4mpic[24m.

       Consider  a  file  [4mdoc/grnexampl.me[24m, which uses the [4mgrn[24m preprocessor to
       include a [4mgremlin[24m(1) picture file in an [4mme[24m document.  Let’s say we want
       to suppress color output, produce a DVI file, and  get  backtraces  for
       any errors that [4mtroff[24m encounters.  The command
              [1mgrog -bc -Idoc -Tdvi doc/grnexmpl.me[0m
       is processed by [4mgrog[24m into
              groff -bc -Idoc -Tdvi -e -g -me doc/grnexmpl.me
       where we can see that [4mgrog[24m has inferred the [4mme[24m macro package along with
       the  [4meqn[24m  and  [4mgrn[24m  preprocessors.  (The input file is located in [4m/usr/[0m
       [4mshare/doc/groff-1.23.0[24m if you’d like to try this example yourself.)

[1mAuthors[0m
       [4mgrog[24m was originally written in Bourne shell by James Clark.   The  cur‐
       rent  implementation  in  Perl was written by Bernd Warken ⟨groff-bernd
       .warken-72@web.de⟩  and  heavily  revised  by   G.   Branden   Robinson
       ⟨g.branden.robinson@gmail.com⟩.

[1mSee also[0m
       [4mgroff[24m(1)

groff 1.23.0                      5 July 2023                          [4mgrog[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrohtml[24m(1)                  General Commands Manual                 [4mgrohtml[24m(1)

[1mName[0m
       grohtml, post-grohtml, pre-grohtml - [4mgroff[24m output driver for HTML

[1mSynopsis[0m
       [1mpre-grohtml [22m[[1m-epV[22m] [[1m-a [4m[22manti‐aliasing‐text‐bits[24m] [[1m-D [4m[22mimage‐directory[24m]
                   [[1m-F [4m[22mfont‐directory[24m] [[1m-g [4m[22manti‐aliasing‐graphic‐bits[24m] [[1m-i[0m
                   [4mresolution[24m] [[1m-I [4m[22mimage‐stem[24m] [[1m-o [4m[22mimage‐vertical‐offset[24m] [[1m-x[0m
                   [4mhtml‐dialect[24m] [4mtroff‐command[24m [4mtroff‐argument[24m ...

       [1mpre-grohtml --help[0m

       [1mpre-grohtml -v[0m
       [1mpre-grohtml --version[0m

       [1mpost-grohtml [22m[[1m-bCGhlnrVy[22m] [[1m-F [4m[22mfont‐directory[24m] [[1m-j [4m[22moutput‐stem[24m] [[1m-s[0m
                    [4mbase‐point‐size[24m] [[1m-S [4m[22mheading‐level[24m] [[1m-x [4m[22mhtml‐dialect[24m]
                    [[4mfile[24m ...]

       [1mpost-grohtml --help[0m

       [1mpost-grohtml -v[0m
       [1mpost-grohtml --version[0m

[1mDescription[0m
       The  GNU  [4mroff[24m  system’s  HTML  support  consists  of  a  preprocessor,
       [4mpre-grohtml[24m, and an output driver, [4mpost-grohtml[24m; together, they  trans‐
       late  [4mroff[24m(7)  documents to HTML.  Because a preprocessor is (uniquely)
       required for this output driver, users should invoke  [4mgrohtml[24m  via  the
       [4mgroff[24m(1)  command with the [1m-Thtml [22mor [1m-Txhtml [22moptions.  (In this instal‐
       lation, [1mps [22mis the default output device.)  Use  [4mgroff[24m’s  [1m-P  [22moption  to
       pass  any options shown above to [4mgrohtml[24m.  If no operands are given, or
       if [4mfile[24m is “[1m-[22m”, [4mgrohtml[24m reads the standard  input  stream.   Output  is
       written to the standard output stream.

       [4mgrohtml[24m  invokes  [4mgroff[24m  twice.   In  the  first pass, the preprocessor
       [4mpre-grohtml[24m renders pictures, equations, and tables as images in  Post‐
       Script format using the [1mps [22moutput device.  In the second pass, the out‐
       put driver [4mpost-grohtml[24m translates the output of [4mtroff[24m(1) to HTML.

       [4mgrohtml[24m  writes  output encoded in UTF‐8 and has built‐in HTML entities
       for all non‐composite Unicode characters.  In spite of this, [4mgroff[24m  may
       issue  warnings about unknown special characters if they can’t be found
       during the first pass.  Such warnings can be safely ignored unless  the
       special characters appear inside a table or equation.

   [1mTypefaces[0m
       [4mgrohtml[24m  supports  the  standard  four styles: [1mR [22m(roman), [1mI [22m([4mitalic[24m), [1mB[0m
       ([1mbold[22m), and [1mBI [22m([4m[1mbold‐italic[24m[22m).  Fonts are grouped into families [1mT [22mand  [1mC[0m
       having members in each style.

              [1mTR     [22mTimes roman
              [1mTI     [22mTimes italic
              [1mTB     [22mTimes bold
              [1mTBI    [22mTimes bold‐italic
              [1mCR     [22mCourier roman
              [1mCI     [22mCourier italic
              [1mCB     [22mCourier bold
              [1mCBI    [22mCourier bold‐italic

       A  special font, [1mS[22m, is also provided to accommodate [4mroff[24m documents that
       expect it to always be available.

   [1mFont description files[0m
       The font description files used with  [4mgrohtml[24m  expose  the  same  glyph
       repertoire in their [1mcharset [22msections.  See [4mgroff_font[24m(5).

   [1mDependencies[0m
       [4mpre-grohtml[24m  generates an image whenever an [4meqn[24m equation, [4mtbl[24m table, or
       [4mpic[24m picture is encountered in the input.   [4mgrohtml[24m  therefore  may  run
       several  commands  as  part of its operation.  These include the Netpbm
       tools [4mpnmcrop[24m, [4mpnmcut[24m, and [4mpnmtopng[24m; Ghostscript ([4mgs[24m); and the  PSUtils
       tool [4mpsselect[24m.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-a [4m[22manti‐aliasing‐text‐bits[0m
              Number of bits of antialiasing information to be  used  by  text
              when  generating  PNG  images.  The default is [1m4 [22mbut [1m0[22m, [1m1[22m, and [1m2[0m
              are also valid.  Your system’s version of [4mgs[24m  must  support  the
              [1m-dTextAlphaBits  [22moption  in  order  to  exploit antialiasing.  A
              value of [1m0 [22mstops [4mgrohtml[24m from issuing antialiasing  commands  to
              [4mgs[24m.

       [1m-b     [22mInitialize the background color to white.

       [1m-C     [22mSuppress output of “CreationDate:” HTML comment.

       [1m-D [4m[22mimage‐directory[0m
              Instruct  [4mgrohtml[24m to place all image files into directory [4mimage‐[0m
              [4mdirectory[24m.

       [1m-e     [22mDirect [4meqn[24m to produce MathML.

              This option should not be manually specified; it is  synthesized
              by [4mgroff[24m depending on whether it was given the [1m-Thtml [22mor [1m-Txhtml[0m
              option.

       [1m-F [4m[22mfont‐directory[0m
              Prepend  directory font‐directory[4m/dev[24mname to the search path for
              font and device description files; [4mname[24m is the name of  the  de‐
              vice, usually [1mhtml[22m.

       [1m-g [4m[22manti‐aliasing‐graphic‐bits[0m
              Number  of bits of antialiasing information to be used by graph‐
              ics when generating PNG images.  The default is [1m4 [22mbut [1m0[22m, [1m1[22m,  and
              [1m2  [22mare also valid.  Your system’s version of [4mgs[24m must support the
              [1m-dGraphicAlphaBits [22moption in order to exploit  antialiasing.   A
              value  of  [1m0 [22mstops [4mgrohtml[24m from issuing antialiasing commands to
              [4mgs[24m.

       [1m-G     [22mSuppress output of “Creator:” HTML comment.

       [1m-h     [22mGenerate section headings by using HTML [1mB [22melements and  increas‐
              ing the font size, rather than HTML [1mH [22melements.

       [1m-i [4m[22mresolution[0m
              Set the image resolution in pixels per inch; the default is [1m100[22m.

       [1m-I [4m[22mimage‐stem[0m
              Determine  the  image  file name stem.  If omitted, [4mgrohtml[24m uses
              [4mgrohtml-[24mXXXXX (where [4mXXXXX[24m is the process ID).  A  dash  is  ap‐
              pended  to the stem to separate it from the following image num‐
              ber.

       [1m-j [4m[22moutput‐stem[0m
              Instruct [4mgrohtml[24m to split the HTML output into  multiple  files.
              Output is written to a new file at each section heading (but see
              option [1m-S [22mbelow) named [4moutput‐stem-[24mn[4m.html[24m.

       [1m-l     [22mTurn off the production of automatic section links at the top of
              the document.

       [1m-n     [22mGenerate  simple heading anchors whenever a section/number head‐
              ing is found.  Without the option the anchor value is  the  tex‐
              tual heading.  This can cause problems when a heading contains a
              “?”  on  older versions of some browsers.  This feature is auto‐
              matically enabled if a heading contains an image.

       [1m-o [4m[22mimage‐vertical‐offset[0m
              Specify the vertical offset of images in points.

       [1m-p     [22mDisplay page rendering progress to the  standard  error  stream.
              [4mgrohtml[24m displays a page number only when an image is required.

       [1m-r     [22mTurn off the automatic header and footer line (HTML rule).

       [1m-s [4m[22mbase‐type‐size[0m
              Set  the document’s base type size in points.  When this size is
              used in the source, it corresponds to the HTML base  type  size.
              Every  increase of two points in the source will produce a “[1mbig[22m”
              element, and conversely when a decrease of two points is seen, a
              “[1msmall[22m” element is emitted.

       [1m-S [4m[22mheading‐level[0m
              When splitting HTML output (see option [1m-j [22mabove), split at  each
              nested  heading level defined by [4mheading‐level[24m, or higher).  The
              default is [1m1[22m.

       [1m-V     [22mCreate an XHTML or HTML validator button at the bottom  of  each
              page of the document.

       [1m-x [4m[22mhtml‐dialect[0m
              Select  HTML  dialect.  Currently, [4mhtml‐dialect[24m should be either
              the digit [1m4 [22mor the letter [1mx[22m,  which  indicates  whether  [4mgrohtml[0m
              should generate HTML 4 or XHTML, respectively.

              This  option should not be manually specified; it is synthesized
              by [4mgroff[24m depending on whether it was given the [1m-Thtml [22mor [1m-Txhtml[0m
              option.

       [1m-y     [22mProduce a right‐aligned [4mgroff[24m signature at the end of the  docu‐
              ment (only if [1m-V [22mis also specified).

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              lists  directories in which to search for [4mdevhtml[24m, [4mgrohtml[24m’s di‐
              rectory of device and font description files.  See [4mtroff[24m(1)  and
              [4mgroff_font[24m(5).

       [4mSOURCE_DATE_EPOCH[0m
              A  timestamp  (expressed as seconds since the Unix epoch) to use
              as the output creation timestamp in place of the  current  time.
              The  time is converted to human‐readable form using [4mctime[24m(3) and
              recorded in an HTML comment.

       [4mTZ[24m     The time zone to use when converting the current time (or  value
              of [4mSOURCE_DATE_EPOCH[24m) to human‐readable form; see [4mtzset[24m(3).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devhtml/DESC[0m
              describes the [1mhtml [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devhtml/[24mF
              describes the font known as [4mF[24m on device [1mhtml[22m.

       [4m/usr/share/groff/1.23.0/tmac/html.tmac[0m
              defines  font  mappings,  special characters, and colors for use
              with the [1mhtml [22moutput device.   It  is  automatically  loaded  by
              [4mtroffrc[24m  when  either of the [1mhtml [22mor [1mxhtml [22moutput devices is se‐
              lected.

       [4m/usr/share/groff/1.23.0/tmac/html-end.tmac[0m
              finalizes setup of the [1mhtml [22moutput device.  It is  automatically
              loaded  by  [4mtroffrc-end[24m  when either of the [1mhtml [22mor [1mxhtml [22moutput
              devices is selected.

       [4mgrohtml[24m uses temporary files.  See [4mgroff[24m(1)  for  details  about  where
       such files are created.

[1mBugs[0m
       [4mgrohtml[24m is still beta code.

       [4mgrohtml[24m  does  not  truly support hyphenation, but you can fool it into
       hyphenating long input lines, which can appear in HTML  output  with  a
       hyphenated word followed by a space but no line break.

[1mSee also[0m
       [4mgroff[24m(1), [4mtroff[24m(1), [4mgroff_font[24m(5)

groff 1.23.0                      5 July 2023                       [4mgrohtml[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrolbp[24m(1)                   General Commands Manual                  [4mgrolbp[24m(1)

[1mName[0m
       grolbp - [4mgroff[24m output driver for Canon CaPSL printers

[1mSynopsis[0m
       [1mgrolbp [22m[[1m-l[22m] [[1m-c [4m[22mnum‐copies[24m] [[1m-F [4m[22mfont‐directory[24m] [[1m-o [4m[22morientation[24m]
              [[1m-p [4m[22mpaper‐format[24m] [[1m-w [4m[22mwidth[24m] [[4mfile[24m ...]
       [1mgrolbp [22m[[1m--copies=[4m[22mnum‐copies[24m] [[1m--fontdir=[4m[22mfont‐directory[24m] [[1m--landscape[22m]
              [[1m--linewidth=[4m[22mwidth[24m] [[1m--orientation=[4m[22morientation[24m]
              [[1m--papersize=[4m[22mpaper‐format[24m] [[4mfile[24m ...]

       [1mgrolbp -h[0m
       [1mgrolbp --help[0m

       [1mgrolbp -v[0m
       [1mgrolbp --version[0m

[1mDescription[0m
       This  GNU  [4mroff[24m  output driver translates the output of [4mtroff[24m(1) into a
       CaPSL and VDM format suitable for Canon LBP‐4 and LBP‐8 printers.  Nor‐
       mally, [4mgrolbp[24m is invoked by [4mgroff[24m(1)  when  the  latter  is  given  the
       “[1m-T  lbp[22m”  option.  (In this installation, [1mps [22mis the default output de‐
       vice.)  Use [4mgroff[24m’s [1m-P [22moption  to  pass  any  options  shown  above  to
       [4mgrolbp[24m.   If  no  [4mfile[24m  arguments  are given, or if [4mfile[24m is “-”, [4mgrolbp[0m
       reads the standard input stream.  Output is  written  to  the  standard
       output stream.

   [1mTypefaces[0m
       The  driver  supports the Dutch, Swiss, and Swiss‐Narrow scalable type‐
       faces, each in the regular, bold, italic, and bold‐italic styles.   Ad‐
       ditionally,  the  bitmapped, monospaced Courier and Elite typefaces are
       available in regular, bold, and italic styles;  Courier  at  8  and  12
       points,  Elite  at 8 and 10 points.  The following chart summarizes the
       [4mgroff[24m font names used to access them.

           ┌───────────────┬─────────┬────────┬──────────┬──────────────┐
           │   [1mTypeface    [22m│  [1mRoman  [22m│  [1mBold  [22m│  [1mItalic  [22m│  [1mBold‐Italic [22m│
           ├───────────────┼─────────┼────────┼──────────┼──────────────┤
           │ Dutch         │  TR     │  TB    │  TI      │  TBI         │
           ├───────────────┼─────────┼────────┼──────────┼──────────────┤
           │ Swiss         │  HR     │  HB    │  HI      │  HBI         │
           ├───────────────┼─────────┼────────┼──────────┼──────────────┤
           │ Swiss Narrow  │  HNR    │  HNB   │  HNI     │  HNBI        │
           ├───────────────┼─────────┼────────┼──────────┼──────────────┤
           │ Courier       │  CR     │  CB    │  CI      │              │
           ├───────────────┼─────────┼────────┼──────────┼──────────────┤
           │ Elite         │  ER     │  EB    │  EI      │              │
           └───────────────┴─────────┴────────┴──────────┴──────────────┘

   [1mPaper format, orientation, and device description file[0m
       [4mgrolbp[24m supports paper formats “[1mA4[22m”, “[1mletter[22m”, “[1mlegal[22m”, and “[1mexecutive[22m”.
       These are matched case‐insensitively.  The [1m-p[22m, [1m--papersize [22moption over‐
       rides any setting in the device  description  file  [4mDESC[24m.   If  neither
       specifies a paper format, A4 is assumed.

       In its [4mDESC[24m file, [4mgrolbp[24m (case‐insensitively) recognizes an [1morientation[0m
       directive accepting one mandatory argument, [1mportrait [22mor [1mlandscape[22m.  The
       first  valid  orientation  directive encountered controls.  The [1m-l[22m, [1m-o[22m,
       and [1m--orientation [22mcommand‐line options override any  setting  in  [4mDESC[24m.
       If none of the foregoing specify the orientation, portrait is assumed.

   [1mFont description files[0m
       In  addition  to  the  font  description  file directives documented in
       [4mgroff_font[24m(5), [4mgrolbp[24m recognizes [1mlbpname[22m, which  maps  the  [4mgroff[24m  font
       name to the font name used internally by the printer.  Its syntax is as
       follows.
              lbpname [4mprinter‐font‐name[0m
       [1mlbpname[22m’s argument is case‐sensitive.  The printer’s font names are en‐
       coded as follows.

       For bitmapped fonts, [4mprinter‐font_name[24m has the form
              N⟨[4mbase‐font‐name[24m⟩⟨[4mfont‐style[24m⟩
       [4mbase‐font‐name[24m  is  the  font  name as it appears in the printer’s font
       listings without the first letter, up to (but not including)  the  font
       size.   [4mfont‐style[24m can be one of the letters [1mR[22m, [1mI[22m, or [1mB[22m, indicating the
       roman, italic, and bold styles, respectively.   For  instance,  if  the
       printer’s “font listing A” shows “Nelite12I.ISO_USA”, the corresponding
       entry in the [4mgroff[24m font description file is
              lbpname NeliteI
       You  may  need to modify [4mgrolbp[24m to add support for new bitmapped fonts,
       since the available font names and font sizes of  bitmapped  fonts  (as
       documented above) are hard‐coded into the program.

       For  scalable fonts, [4mprinter‐font‐name[24m is identical to the font name as
       it appears in the printer’s “font listing A”.  For instance, to  select
       the  “Swiss” font in bold‐italic style, which appears in the font list‐
       ing as “Swiss-BoldOblique”,
              lbpname Swiss-BoldOblique
       is the required directive, and this is what we find in the  [4mgroff[24m  font
       description file [4mHBI[24m for the [1mlbp [22mdevice.

   [1mDrawing commands[0m
       For  compatibility  with  [4mgrolj4[24m(1),  an  additional drawing command is
       available.

       [1m\D'R [4m[22mdh[24m [4mdv[24m[1m'[0m
              Draw a rule (solid black rectangle) with one corner at the draw‐
              ing position, and the diagonally opposite corner at the  drawing
              position +([4mdh[24m,[4mdv[24m).

[1mOptions[0m
       [1m-h [22mand [1m--help [22mdisplay a usage message, while [1m-v [22mand [1m--version [22mshow ver‐
       sion information; all exit afterward.

       [1m-c [4m[22mnum‐copies[0m
       [1m--copies=[4m[22mnum‐copies[0m
              Produce [4mnum‐copies[24m copies of each page.

       [1m-F [4m[22mfont‐directory[0m
       [1m--fontdir=[4m[22mfont‐directory[0m
              Prepend  directory font‐directory[4m/dev[24mname to the search path for
              font and device description files; [4mname[24m is the name of  the  de‐
              vice, usually [1mlbp[22m.

       [1m-l[0m
       [1m--landscape[0m
              Format the document in landscape orientation.

       [1m-o [4m[22morientation[0m
       [1m--orientation=[4m[22morientation[0m
              Format  the  document  in  the  given [4morientation[24m, which must be
              “[1mportrait[22m” or “[1mlandscape[22m”.

       [1m-p [4m[22mpaper‐format[0m
       [1m--papersize=[4m[22mpaper‐format[0m
              Set the paper format to [4mpaper‐format[24m, which must be a valid  pa‐
              per format as described above.

       [1m-w [4m[22mwidth[0m
       [1m--linewidth=[4m[22mwidth[0m
              Set  the  default  line thickness to [4mwidth[24m thousandths of an em;
              the default is [1m40 [22m(0.04 em).

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              lists directories in which to seek the selected output  device’s
              directory  of  device  and font description files.  See [4mtroff[24m(1)
              and [4mgroff_font[24m(5).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devlbp/DESC[0m
              describes the [1mlbp [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devlbp/[24mF
              describes the font known as [4mF[24m on device [1mlbp[22m.

       [4m/usr/share/groff/1.23.0/tmac/lbp.tmac[0m
              defines macros for use with the [1mlbp [22moutput device.  It is  auto‐
              matically  loaded  by  [4mtroffrc[24m when the [1mlbp [22moutput device is se‐
              lected.

[1mSee also[0m
       [4mgroff[24m(1), [4mtroff[24m(1), [4mgroff_out[24m(5), [4mgroff_font[24m(5), [4mgroff_char[24m(7)

groff 1.23.0                      5 July 2023                        [4mgrolbp[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrolj4[24m(1)                   General Commands Manual                  [4mgrolj4[24m(1)

[1mName[0m
       grolj4 - [4mgroff[24m output driver for HP LaserJet 4 and compatible printers

[1mSynopsis[0m
       [1mgrolj4 [22m[[1m-l[22m] [[1m-c [4m[22mnum‐copies[24m] [[1m-d [22m[[4mn[24m]] [[1m-F [4m[22mfont‐directory[24m] [[1m-p [4m[22mpaper‐[0m
              [4mformat[24m] [[1m-w [4m[22mline‐width[24m] [[4mfile[24m ...]

       [1mgrolj4 --help[0m

       [1mgrolj4 -v[0m
       [1mgrolj4 --version[0m

[1mDescription[0m
       This GNU [4mroff[24m output driver translates the output of  [4mtroff[24m(1)  into  a
       PCL5 format suitable for an HP LaserJet 4 printer.  Normally, [4mgrolj4[24m is
       invoked  by [4mgroff[24m(1) when the latter is given the “[1m-T lj4[22m” option.  (In
       this installation, [1mps [22mis the default output device.)   Use  [4mgroff[24m’s  [1m-P[0m
       option to pass any options shown above to [4mgrolj4[24m.  If no [4mfile[24m arguments
       are  given,  or if [4mfile[24m is “-”, [4mgrolj4[24m reads the standard input stream.
       Output is written to the standard output stream.

   [1mTypefaces[0m
       [4mgrolj4[24m supports the standard four styles:  [1mR  [22m(roman),  [1mI  [22m([4mitalic[24m),  [1mB[0m
       ([1mbold[22m), and [1mBI [22m([4m[1mbold‐italic[24m[22m).  Fonts are grouped into families [1mA[22m, [1mC[22m, [1mG[22m,
       [1mO[22m, [1mT[22m, [1mTN[22m, [1mU[22m, and [1mUC [22mhaving members in each style.

              [1mAB            [22mArial Bold
              [1mABI           [22mArial Bold Italic
              [1mAI            [22mArial Italic
              [1mAR            [22mArial Roman
              [1mCB            [22mCourier Bold
              [1mCBI           [22mCourier Bold Italic
              [1mCI            [22mCourier Italic
              [1mCR            [22mCourier Roman
              [1mGB            [22mGaramond Halbfett
              [1mGBI           [22mGaramond Kursiv Halbfett
              [1mGI            [22mGaramond Kursiv
              [1mGR            [22mGaramond Antiqua
              [1mOB            [22mCG Omega Bold
              [1mOBI           [22mCG Omega Bold Italic
              [1mOI            [22mCG Omega Italic
              [1mOR            [22mCG Omega Roman
              [1mOB            [22mCG Omega Bold
              [1mOBI           [22mCG Omega Bold Italic
              [1mOI            [22mCG Omega Italic
              [1mOR            [22mCG Omega Roman
              [1mTB            [22mCG Times Bold
              [1mTBI           [22mCG Times Bold Italic
              [1mTI            [22mCG Times Italic
              [1mTR            [22mCG Times Roman
              [1mTNRB          [22mM Times Bold
              [1mTNRBI         [22mM Times Bold Italic
              [1mTNRI          [22mM Times Italic
              [1mTNRR          [22mM Times Roman
              [1mUB            [22mUnivers Bold
              [1mUBI           [22mUnivers Bold Italic
              [1mUI            [22mUnivers Medium Italic
              [1mUR            [22mUnivers Medium
              [1mUCB           [22mUnivers Condensed Bold
              [1mUCBI          [22mUnivers Condensed Bold Italic
              [1mUCI           [22mUnivers Condensed Medium Italic
              [1mUCR           [22mUnivers Condensed Medium

       The following fonts are not members of a family.

              [1mALBB          [22mAlbertus Extra Bold
              [1mALBR          [22mAlbertus Medium
              [1mAOB           [22mAntique Olive Bold
              [1mAOI           [22mAntique Olive Italic
              [1mAOR           [22mAntique Olive Roman
              [1mCLARENDON     [22mClarendon
              [1mCORONET       [22mCoronet
              [1mLGB           [22mLetter Gothic Bold
              [1mLGI           [22mLetter Gothic Italic
              [1mLGR           [22mLetter Gothic Roman
              [1mMARIGOLD      [22mMarigold

       The  special  font  is  [1mS  [22m(PostScript  Symbol); [1mSYMBOL [22m(M Symbol), and
       [1mWINGDINGS [22m(Wingdings) are also available but not mounted by default.

   [1mPaper format and device description file[0m
       [4mgrolj4[24m  supports  paper  formats  “[1mA4[22m”,  “[1mB5[22m”,  “[1mC5[22m”,  “[1mcom10[22m”,   “[1mDL[22m”,
       “[1mexecutive[22m”, “[1mlegal[22m”, “[1mletter[22m”, and “[1mmonarch[22m”.  These are matched case‐
       insensitively.   The  [1m-p [22moption overrides any setting in the device de‐
       scription file [4mDESC[24m.  If neither specifies a paper format, “letter”  is
       assumed.

   [1mFont description files[0m
       [4mgrolj4[24m  recognizes four font description file directives in addition to
       those documented in [4mgroff_font[24m(5).

       [1mpclweight [4m[22mn[0m
              Set the stroke weight to [4mn[24m, an integer in the range  -7  to  +7;
              the default is 0.

       [1mpclstyle [4m[22mn[0m
              Set  the style to [4mn[24m, an integer in the range 0 to 32767; the de‐
              fault is 0.

       [1mpclproportional [4m[22mn[0m
              Set the proportional spacing Boolean flag to [4mn[24m, which can be ei‐
              ther 0 or 1; the default is 0.

       [1mpcltypeface [4m[22mn[0m
              Set the typeface family to [4mn[24m, an  integer  in  the  range  0  to
              65535; the default is 0.

   [1mDrawing commands[0m
       An  additional  drawing  command is recognized as an extension to those
       documented in [4mgroff[24m(7).

       [1m\D'R [4m[22mdh[24m [4mdv[24m[1m'[0m
              Draw a rule (solid black rectangle) with one corner at the draw‐
              ing position, and the diagonally opposite corner at the  drawing
              position  +([4mdh[24m,[4mdv[24m), at which the drawing position will be after‐
              ward.  This generates a PCL fill rectangle command, and so  will
              work  on  printers that do not support HP‐GL/2, unlike the other
              [1m\D [22mcommands.

   [1mFonts[0m
       Nominally, all Hewlett‐Packard LaserJet  4‐series  and  newer  printers
       have  the  same  internal  fonts:  45  scalable fonts and one bitmapped
       Lineprinter font.  The scalable fonts are available  in  sizes  between
       0.25   points   and   999.75  points,  in  0.25‐point  increments;  the
       Lineprinter font is available only in 8.5‐point size.

       The LaserJet font files included with [4mgroff[24m assume  that  all  printers
       since the LaserJet 4 are identical.  There are some differences between
       fonts in the earlier and more recent printers, however.  The LaserJet 4
       printer  used  Agfa Intellifont technology for 35 of the internal scal‐
       able fonts; the remaining 10 scalable fonts were  TrueType.   Beginning
       with the LaserJet 4000‐series printers introduced in 1997, all scalable
       internal fonts have been TrueType.  The number of printable glyphs dif‐
       fers  slightly  between  Intellifont and TrueType fonts (generally, the
       TrueType fonts include more glyphs), and there are some  minor  differ‐
       ences in glyph metrics.  Differences among printer models are described
       in  the  [4mPCL[24m [4m5[24m [4mComparison[24m [4mGuide[24m and the [4mPCL[24m [4m5[24m [4mComparison[24m [4mGuide[24m [4mAddendum[0m
       (for printers introduced since approximately 2001).

       LaserJet printers reference a glyph by a  combination  of  a  256‐glyph
       symbol  set and an index within that symbol set.  Many glyphs appear in
       more than one symbol set; all combinations of symbol set and index that
       reference the same glyph are equivalent.  For each  glyph,  [4mhpftodit[24m(1)
       searches a list of symbol sets, and selects the first set that contains
       the  glyph.  The printing code generated by [4mhpftodit[24m is an integer that
       encodes a numerical value for the symbol set in the high  byte(s),  and
       the  index  in the low byte.  See [4mgroff_font[24m(5) for a complete descrip‐
       tion of the font file format; symbol sets are described in greater  de‐
       tail in the [4mPCL[24m [4m5[24m [4mPrinter[24m [4mLanguage[24m [4mTechnical[24m [4mReference[24m [4mManual[24m.

       Two of the scalable fonts, Symbol and Wingdings, are bound to 256‐glyph
       symbol  sets;  the remaining scalable fonts, as well as the Lineprinter
       font, support numerous symbol sets, sufficient to  enable  printing  of
       more than 600 glyphs.

       The  metrics  generated  by [4mhpftodit[24m assume that the [4mDESC[24m file contains
       values of 1200 for [4mres[24m and  6350  for  [4munitwidth[24m,  or  any  combination
       (e.g., 2400 and 3175) for which [4mres[24m × [4munitwidth[24m = 7620000.  Although HP
       PCL  5  LaserJet  printers support an internal resolution of 7200 units
       per inch, they use a 16‐bit signed integer for positioning;  if  [1mdevlj4[0m
       is to support U.S. ledger paper (11 in × 17 in; in = inch), the maximum
       usable  resolution  is 32767 ÷ 17, or 1927 units per inch, which rounds
       down to 1200 units per inch.  If the largest required  paper  dimension
       is  less  (e.g.,  8.5  in  ×  11  in, or A5), a greater [4mres[24m (and lesser
       [4munitwidth[24m) can be specified.

       Font metrics for Intellifont fonts were provided by Tagged Font  Metric
       (TFM)  files  originally developed by Agfa/Compugraphic.  The TFM files
       provided for these fonts supported 600+ glyphs and contained  extensive
       lists of kerning pairs.

       To  accommodate  developers  who had become accustomed to TFM files, HP
       also provided TFM files for the  10  TrueType  fonts  included  in  the
       LaserJet  4.   The TFM files for TrueType fonts generally included less
       information than the Intellifont TFMs, supporting fewer glyphs, and  in
       most  cases,  providing no kerning information.  By the time the Laser‐
       Jet 4000 printer was introduced, most developers had migrated to  other
       means of obtaining font metrics, and support for new TFM files was very
       limited.   The  TFM files provided for the TrueType fonts in the Laser‐
       Jet 4000 support only the Latin 2 (ISO 8859‐2) symbol set, and  include
       no  kerning information; consequently, they are of little value for any
       but the most rudimentary documents.

       Because the Intellifont TFM files contain  considerably  more  informa‐
       tion,  they generally are preferable to the TrueType TFM files even for
       use with the TrueType fonts in the newer printers.  The metrics for the
       TrueType fonts are very close, though not identical, to those  for  the
       earlier  Intellifont fonts of the same names.  Although most output us‐
       ing the Intellifont metrics with the newer printers  is  quite  accept‐
       able,  a  few glyphs may fail to print as expected.  The differences in
       glyph metrics may be particularly noticeable with  composite  parenthe‐
       ses,  brackets,  and braces used by [4meqn[24m(1).  A script, located in [4m/usr/[0m
       [4mshare/groff/1.23.0/font/devlj4/generate[24m, can be used to adjust the met‐
       rics for these glyphs in the special font “S”  for  use  with  printers
       that have all TrueType fonts.

       At  the  time HP last supported TFM files, only version 1.0 of the Uni‐
       code standard was available.  Consequently,  many  glyphs  lacking  as‐
       signed  code  points were assigned by HP to the Private Use Area (PUA).
       Later versions of the Unicode standard included code points outside the
       PUA for many of these glyphs.  The HP‐supplied TrueType TFM  files  use
       the PUA assignments; TFM files generated from more recent TrueType font
       files require the later Unicode values to access the same glyphs.  Con‐
       sequently, two different mapping files may be required: one for the HP‐
       supplied TFM files, and one for more recent TFM files.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-c [4m[22mnum‐copies[0m
              Format [4mnum‐copies[24m copies of each page.

       [1m-d [22m[[4mn[24m] Use duplex mode [4mn[24m: 1 is long‐side binding (default),  and  2  is
              short‐side binding.

       [1m-F [4m[22mfont‐directory[0m
              Prepend  directory [4mfont‐directory[24m/dev[4mname[24m to the search path for
              font and device description files; [4mname[24m is the name of  the  de‐
              vice, usually [1mlj4[22m.

       [1m-l     [22mFormat the document in landscape orientation.

       [1m-p [4m[22mpaper‐format[0m
              Set  the paper format to [4mpaper‐format[24m, which must be a valid pa‐
              per format as described above.

       [1m-w [4m[22mline‐width[0m
              Set the default line thickness to [4mline‐width[24m thousandths  of  an
              em; the default is [1m40 [22m(0.04 em).

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              lists  directories in which to seek the selected output device’s
              directory of device and font description  files.   See  [4mtroff[24m(1)
              and [4mgroff_font[24m(5).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devlj4/DESC[0m
              describes the [1mlj4 [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devlj4/[24mF
              describes the font known as [4mF[24m on device [1mlj4[22m.

       [4m/usr/share/groff/1.23.0/tmac/lj4.tmac[0m
              defines  macros for use with the [1mlj4 [22moutput device.  It is auto‐
              matically loaded by [4mtroffrc[24m when the [1mlj4 [22moutput  device  is  se‐
              lected.

[1mBugs[0m
       Small dots.

[1mSee also[0m
       [4mHP[24m  [4mPCL/PJL[24m  [4mReference:[24m [4mPCL[24m [4m5[24m [4mPrinter[24m [4mLanguage[24m [4mTechnical[24m [4mReference[24m [4mMan‐[0m
       [4mual,[24m [4mPart[24m [4mI[24m ⟨http://www.hp.com/ctg/Manual/bpl13210.pdf⟩

       [4mhpftodit[24m(1),   [4mgroff[24m(1),   [4mtroff[24m(1),    [4mgroff_out[24m(5),    [4mgroff_font[24m(5),
       [4mgroff_char[24m(7)

groff 1.23.0                      5 July 2023                        [4mgrolj4[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgropdf[24m(1)                   General Commands Manual                  [4mgropdf[24m(1)

[1mName[0m
       gropdf - [4mgroff[24m output driver for Portable Document Format

[1mSynopsis[0m
       [1mgropdf [22m[[1m-dels[22m] [[1m-F [4m[22mfont‐directory[24m] [[1m-I [4m[22minclusion‐directory[24m] [[1m-p [4m[22mpaper‐[0m
              [4mformat[24m] [[1m-u [22m[[4mcmap‐file[24m]] [[1m-y [4m[22mfoundry[24m] [[4mfile[24m ...]

       [1mgropdf --help[0m

       [1mgropdf -v[0m
       [1mgropdf --version[0m

[1mDescription[0m
       The  GNU  [4mroff[24m PDF output driver translates the output of [4mtroff[24m(1) into
       Portable Document Format.  Normally, [4mgropdf[24m is invoked by [4mgroff[24m(1) when
       the latter is given the “[1m-T pdf[22m” option.  (In this installation, [1mps  [22mis
       the  default output device.)  Use [4mgroff[24m’s [1m-P [22moption to pass any options
       shown above to [4mgropdf[24m.  If no [4mfile[24m arguments are given, or if  [4mfile[24m  is
       “-”,  [4mgropdf[24m reads the standard input stream.  Output is written to the
       standard output stream.

       See section “Font installation” below for a guide to  installing  fonts
       for [4mgropdf[24m.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-d     [22mInclude debug information as comments within the PDF.  Also pro‐
              duces an uncompressed PDF.

       [1m-e     [22mForces [4mgropdf[24m to embed [4mall[24m fonts (even the 14 base PDF fonts).

       [1m-F [4m[22mdir[24m Prepend directory [4mdir[24m/dev[4mname[24m to the search path for  font,  and
              device  description  files; [4mname[24m is the name of the device, usu‐
              ally [1mpdf[22m.

       [1m-I [4m[22mdir[24m Search the directory [4mdir[24m for files named in [1m\X'pdf: pdfpic'  [22mde‐
              vice control commands.  [1m-I [22mmay be specified more than once; each
              [4mdir[24m is searched in the given order.  To search the current work‐
              ing directory before others, add “[1m-I .[22m” at the desired place; it
              is otherwise searched last.

       [1m-l     [22mOrient the document in landscape format.

       [1m-p [4m[22mpaper‐format[0m
              Set  the  physical  dimensions of the output medium.  This over‐
              rides the [1mpapersize[22m, [1mpaperlength[22m, and [1mpaperwidth  [22mdirectives  in
              the  [4mDESC[24m  file;  it accepts the same arguments as the [1mpapersize[0m
              directive.  See [4mgroff_font[24m(5) for details.

       [1m-s     [22mAppend a comment line to end of  PDF  showing  statistics,  i.e.
              number  of  pages  in  document.  Ghostscript’s [1mps2pdf [22mcomplains
              about this line if it is included, but works anyway.

       [1m-u [22m[[4mcmap‐file[24m]
              [4mgropdf[24m normally includes a ToUnicode CMap with any font  created
              using  [4mtext.enc[24m  as  the  encoding file, this makes it easier to
              search for words which contain ligatures.  You can include  your
              own  CMap  by  specifying  a [4mcmap‐file[24m or have no CMap at all by
              omitting the argument.

       [1m-y [4m[22mfoundry[0m
              Set the foundry to use for selecting fonts of the same name.

[1mUsage[0m
       The input to [4mgropdf[24m must be in the format output by [4mtroff[24m(1).  This  is
       described  in  [4mgroff_out[24m(5).  In addition, the device and font descrip‐
       tion files for the device used must meet certain requirements: The res‐
       olution must be an integer multiple of 72 times the [1msizescale[22m.  The [1mpdf[0m
       device uses a resolution of 72000 and a sizescale of 1000.

       The device description file must contain  a  valid  paper  format;  see
       [4mgroff_font[24m(5).   [4mgropdf[24m  uses the same Type 1 Adobe PostScript fonts as
       the [1mgrops [22mdevice driver.  Although the PDF Standard allows the  use  of
       other  font  types (like TrueType) this implementation only accepts the
       Type 1 PostScript font.  Fewer Type 1 fonts are supported  natively  in
       PDF  documents  than  the  standard 35 fonts supported by [1mgrops [22mand all
       PostScript printers, but all the fonts are available  since  any  which
       aren’t supported natively are automatically embedded in the PDF.

       [4mgropdf[24m supports the concept of foundries, that is different versions of
       basically  the same font.  During install a [4mFoundry[24m file controls where
       fonts are found and builds [4mgroff[24m fonts from the files it  discovers  on
       your system.

       Each font description file must contain a command

              [1minternalname [4m[22mpsname[0m

       which  says  that  the  PostScript  name  of the font is [4mpsname[24m.  Lines
       starting with [1m# [22mand blank lines are ignored.  The code for each charac‐
       ter given in the font file must correspond to the code in  the  default
       encoding  for  the  font.  This code can be used with the [1m\N [22mescape se‐
       quence in [1mtroff [22mto select the character, even if the character does not
       have a [4mgroff[24m name.  Every character in the font file must exist in  the
       PostScript  font,  and the widths given in the font file must match the
       widths used in the PostScript font.

       Note that [4mgropdf[24m is currently only able to display the first 256 glyphs
       in any font.  This restriction will be lifted in a later version.

       [4mgropdf[24m can automatically include the downloadable  fonts  necessary  to
       print the document.  Fonts may be in PFA or PFB format.

       Any  downloadable  fonts  which  should,  when required, be included by
       [4mgropdf[24m must be listed in the file  [4m/usr/share/groff/1.23.0/font/devpdf/[0m
       [4mdownload[24m; this should consist of lines of the form

              [4mfoundry[24m [4mfont[24m [4mfilename[0m

       where  [4mfoundry[24m  is  the  foundry name or blank for the default foundry.
       [4mfont[24m is the PostScript name of the font, and [4mfilename[24m is  the  name  of
       the  file  containing  the font; lines beginning with [1m# [22mand blank lines
       are ignored; fields must be separated by tabs (spaces are [1mnot [22mallowed);
       [4mfilename[24m is searched for using the same  mechanism  that  is  used  for
       [4mgroff[24m font metric files.  The [4mdownload[24m file itself is also sought using
       this  mechanism.  Foundry names are usually a single character (such as
       ‘U’ for the URW foundry) or empty for the default  foundry.   This  de‐
       fault uses the same fonts as [4mghostscript[24m uses when it embeds fonts in a
       PDF file.

       In the default setup there are styles called [1mR[22m, [1mI[22m, [1mB[22m, and [1mBI [22mmounted at
       font  positions  1 to 4.  The fonts are grouped into families [1mA[22m, [1mBM[22m, [1mC[22m,
       [1mH[22m, [1mHN[22m, [1mN[22m, [1mP[22m, and [1mT [22mhaving members in each of these styles:

              [1mAR     [22mAvantGarde‐Book
              [1mAI     [22mAvantGarde‐BookOblique
              [1mAB     [22mAvantGarde‐Demi
              [1mABI    [22mAvantGarde‐DemiOblique
              [1mBMR    [22mBookman‐Light
              [1mBMI    [22mBookman‐LightItalic
              [1mBMB    [22mBookman‐Demi
              [1mBMBI   [22mBookman‐DemiItalic
              [1mCR     [22mCourier
              [1mCI     [22mCourier‐Oblique
              [1mCB     [22mCourier‐Bold
              [1mCBI    [22mCourier‐BoldOblique
              [1mHR     [22mHelvetica
              [1mHI     [22mHelvetica‐Oblique
              [1mHB     [22mHelvetica‐Bold
              [1mHBI    [22mHelvetica‐BoldOblique
              [1mHNR    [22mHelvetica‐Narrow
              [1mHNI    [22mHelvetica‐Narrow‐Oblique
              [1mHNB    [22mHelvetica‐Narrow‐Bold
              [1mHNBI   [22mHelvetica‐Narrow‐BoldOblique
              [1mNR     [22mNewCenturySchlbk‐Roman
              [1mNI     [22mNewCenturySchlbk‐Italic
              [1mNB     [22mNewCenturySchlbk‐Bold
              [1mNBI    [22mNewCenturySchlbk‐BoldItalic
              [1mPR     [22mPalatino‐Roman
              [1mPI     [22mPalatino‐Italic
              [1mPB     [22mPalatino‐Bold
              [1mPBI    [22mPalatino‐BoldItalic
              [1mTR     [22mTimes‐Roman
              [1mTI     [22mTimes‐Italic
              [1mTB     [22mTimes‐Bold
              [1mTBI    [22mTimes‐BoldItalic

       There is also the following font which is not a member of a family:

              [1mZCMI   [22mZapfChancery‐MediumItalic

       There are also some special fonts called [1mS [22mfor the PS Symbol font.  The
       lower case greek characters are automatically  slanted  (to  match  the
       SymbolSlanted  font  (SS)  available  to PostScript).  Zapf Dingbats is
       available as [1mZD[22m; the “hand pointing left” glyph  ([1m\[lh][22m)  is  available
       since  it  has been defined using the [1m\X'pdf: xrev' [22mdevice control com‐
       mand, which reverses the direction of letters within words.

       The default color for [1m\m [22mand [1m\M [22mis black.

       [4mgropdf[24m understands some of the device  control  commands  supported  by
       [4mgrops[24m(1).

       [1m\X'ps: invis'[0m
              Suppress output.

       [1m\X'ps: endinvis'[0m
              Stop suppressing output.

       [1m\X'ps: exec gsave currentpoint 2 copy translate [4m[22mn[24m [1mrotate neg exch neg[0m
       [1mexch translate'[0m
              where  [4mn[24m is the angle of rotation.  This is to support the [1malign[0m
              command in [4mpic[24m(1).

       [1m\X'ps: exec grestore'[0m
              Used by [4mpic[24m(1) to restore state after rotation.

       [1m\X'ps: exec [4m[22mn[24m [1msetlinejoin'[0m
              where [4mn[24m can be one of the following values.

              0 = Miter join
              1 = Round join
              2 = Bevel join

       [1m\X'ps: exec [4m[22mn[24m [1msetlinecap'[0m
              where [4mn[24m can be one of the following values.

              0 = Butt cap
              1 = Round cap, and
              2 = Projecting square cap

       [1m\X'ps: [22m... [1mpdfmark'[0m
              All the [4mpdfmark[24m macros installed by using [4m-m[24m [4mpdfmark[24m or [4m-m[24m [4mmspdf[0m
              (see documentation in [4mpdfmark.pdf[24m).  A subset  of  these  macros
              are installed automatically when you use [1m-Tpdf [22mso you should not
              need to use “[1m-m pdfmark[22m” to access most PDF functionality.

       [4mgropdf[24m   also   supports   a  subset  of  the  commands  introduced  in
       [4mpresent.tmac[24m.  Specifically it supports:‐

              PAUSE
              BLOCKS
              BLOCKE

       Which allows you to create presentation type PDFs.  Many of  the  other
       commands are already available in other macro packages.

       These commands are implemented with [4mgroff[24m X commands:‐

       [1m\X'ps: exec %%%%PAUSE'[0m
              The  section before this is treated as a block and is introduced
              using the current [1mBLOCK [22mtransition setting (see “[1m\X'pdf: transi‐[0m
              [1mtion'[22m” below).  Equivalently, [1m.pdfpause [22mis available as a macro.

       [1m\X'ps: exec %%%%BEGINONCE'[0m
              Any text following this command (up  to  %%%%ENDONCE)  is  shown
              only  once,  the  next %%%%PAUSE will remove it.  If producing a
              non‐presentation   PDF,   i.e.   ignoring   the   pauses,    see
              [4mGROPDF_NOSLIDE[24m below, this text is ignored.

       [1m\X'ps: exec %%%%ENDONCE'[0m
              This  terminates  the block defined by %%%%BEGINONCE.  This pair
              of commands is what implements the .BLOCKS Once/.BLOCKE commands
              in [4mpresent.tmac[24m.

       The [4mmom[24m macro package already integrates these extensions, so  you  can
       build slides with [4mmom[24m.

       If you use [4mpresent.tmac[24m with [4mgropdf[24m there is no need to run the program
       [4mpresentps[24m(1) since the output will already be a presentation PDF.

       All other [1mps: [22mtags are silently ignored.

       One  [1m\X  [22mdevice  control  command used by the DVI driver is also recog‐
       nised.

       [1m\X'papersize=[4m[22mpaper‐format[24m[1m'[0m
              where the [4mpaper‐format[24m parameter is the same as that to the  [1mpa‐[0m
              [1mpersize  [22mdirective.  See [4mgroff_font[24m(5).  This means that you can
              alter the page size at will within the PDF file being created by
              [4mgropdf[24m.  If you do want to change the paper format, it  must  be
              done before you start creating the page.

       [4mgropdf[24m  supports  several  more  device control features using the [1mpdf:[0m
       tag.  Some have counterpart [4mconvenience[24m [4mmacros[24m that take the same argu‐
       ments and behave equivalently.

       [1m\X'pdf: pdfpic [4m[22mfile[24m [4malignment[24m [4mwidth[24m [4mheight[24m [4mline‐length[24m'
              Place an image of the specified [4mwidth[24m containing the PDF drawing
              from file [4mfile[24m of desired [4mwidth[24m and [4mheight[24m (if [4mheight[24m is missing
              or zero then it is scaled proportionally).  If [4malignment[24m  is  [1m-L[0m
              the  drawing  is  left‐aligned.  If it is [1m-C [22mor [1m-R [22ma [4mline‐length[0m
              greater than the width of the drawing is required as  well.   If
              [4mwidth[24m  is  specified as zero then the width is scaled in propor‐
              tion to the height.

       [1m\X'pdf: xrev'[0m
              Toggle the reversal of  glyph  direction.   This  feature  works
              “letter  by  letter”, that is, each letter in a word is reversed
              left‐to‐right, not the entire word.  One application is the  re‐
              versal of glyphs in the Zapf Dingbats font.  To restore the nor‐
              mal glyph orientation, repeat the command.

       [1m\X'pdf: markstart [4m[22m/ANN‐definition[24m[1m'[0m
       [1m\X'pdf: markend'[0m
              Macros  that support PDF bookmarks use these calls internally to
              start and stop (respectively) the placement  of  the  bookmark’s
              [4mhot[24m  [4mspot;[24m  the user will have called “[1m.pdfhref L[22m” with the text
              of the hot spot.  Normally, these are  never  used  except  from
              within the [4mpdfmark[24m macros.

       [1m\X'pdf: marksuspend'[0m
       [1m\X'pdf: markrestart'[0m
              If  you  use a page location trap to produce a header or footer,
              or otherwise interrupt a document’s text, you need to use  these
              commands  if  a  PDF [4mhot[24m [4mspot[24m crosses a trap boundary; otherwise
              any text output by the trap will be marked as part  of  the  hot
              spot.   To  prevent  this error, place these device control com‐
              mands or their corresponding convenience macros  [1m.pdfmarksuspend[0m
              and  [1m.pdfmarkrestart [22mat the start and end of the trap macro, re‐
              spectively.

       [1m\X'pdf: pagename [4m[22mname[24m[1m'[0m
              Assign the current page a [4mname[24m.  All documents bear two  default
              names,  ‘[1mtop[22m’ and ‘[1mbottom[22m’.  The convenience macro for this com‐
              mand is [1m.pdfpagename[22m.

       [1m\X’pdf: switchtopage [4m[22mwhen[24m [4mname[24m[1m'[0m
              Normally each new page is appended to the end of  the  document,
              this  command allows following pages to be inserted at a [4m‘named’[0m
              position within  the  document  (see  pagename  command  above).
              [4m‘when’[24m  can  be either ‘[4mafter[24m’ or ‘[4mbefore[24m’.  If it is omitted it
              defaults to ‘[4mbefore[24m’.  It should be used at the end of the  page
              before you want the switch to happen.  This allows pages such as
              a  TOC  to  be moved to elsewhere in the document, but more eso‐
              teric uses are possible.  The convenience macro for this command
              is [1m.pdfswitchtopage[22m.

       [1m\X'pdf: transition [4m[22mfeature[24m [4mmode[24m [4mduration[24m [4mdimension[24m [4mmotion[24m [4mdirection[0m
       [4mscale[24m [4mbool[24m[1m'[0m
              where [4mfeature[24m can be either SLIDE or BLOCK.  When  it  is  SLIDE
              the  transition  is  used  when a new slide is introduced to the
              screen, if BLOCK then this transition is used for the individual
              blocks which make up the slide.

              [4mmode[24m is the transition type between slides:‐

                     [1mSplit [22m‐ Two lines sweep across the screen, revealing  the
                     new page.  The lines may be either horizontal or vertical
                     and may move inward from the edges of the page or outward
                     from the center, as specified by the [4mdimension[24m and [4mmotion[0m
                     entries, respectively.
                     [1mBlinds [22m‐ Multiple lines, evenly spaced across the screen,
                     synchronously  sweep  in the same direction to reveal the
                     new page.  The lines may be either horizontal  or  verti‐
                     cal,  as  specified  by  the [4mdimension[24m entry.  Horizontal
                     lines move downward; vertical lines move to the right.
                     [1mBox [22m‐ A rectangular box sweeps inward from the  edges  of
                     the  page or outward from the center, as specified by the
                     [4mmotion[24m entry, revealing the new page.
                     [1mWipe [22m‐ A single line sweeps across the  screen  from  one
                     edge  to  the other in the direction specified by the [4mdi‐[0m
                     [4mrection[24m entry, revealing the new page.
                     [1mDissolve [22m‐ The old page dissolves gradually to reveal the
                     new one.
                     [1mGlitter [22m‐ Similar to Dissolve,  except  that  the  effect
                     sweeps  across  the  page  in a wide band moving from one
                     side of the screen to the other in the  direction  speci‐
                     fied by the [4mdirection[24m entry.
                     [1mR [22m‐ The new page simply replaces the old one with no spe‐
                     cial  transition effect; the [4mdirection[24m entry shall be ig‐
                     nored.
                     [1mFly [22m‐ (PDF 1.5) Changes are flown out or in (as specified
                     by [4mmotion[24m), in the direction specified by  [4mdirection[24m,  to
                     or  from  a location that is offscreen except when [4mdirec‐[0m
                     [4mtion[24m is [1mNone[22m.
                     [1mPush [22m‐ (PDF 1.5) The old page slides off the screen while
                     the new page slides in, pushing the old page out  in  the
                     direction specified by [4mdirection[24m.
                     [1mCover [22m‐ (PDF 1.5) The new page slides on to the screen in
                     the  direction  specified  by [4mdirection[24m, covering the old
                     page.
                     [1mUncover [22m‐ (PDF 1.5) The old page slides off the screen in
                     the direction specified by [4mdirection[24m, uncovering the  new
                     page in the direction specified by [4mdirection[24m.
                     [1mFade  [22m‐  (PDF 1.5) The new page gradually becomes visible
                     through the old one.

              [4mduration[24m is the length of the transition in seconds (default 1).

              [4mdimension[24m (Optional; [1mSplit [22mand [1mBlinds  [22mtransition  styles  only)
              The dimension in which the specified transition effect shall oc‐
              cur: [1mH [22mHorizontal, or [1mV [22mVertical.

              [4mmotion[24m (Optional; [1mSplit[22m, [1mBox [22mand [1mFly [22mtransition styles only) The
              direction  of  motion for the specified transition effect: [1mI [22mIn‐
              ward from the edges of the page, or [1mO [22mOutward from the center of
              the page.

              [4mdirection[24m (Optional; [1mWipe[22m, [1mGlitter[22m, [1mFly[22m, [1mCover[22m, [1mUncover [22mand [1mPush[0m
              transition styles only) The direction  in  which  the  specified
              transition  effect  shall  moves,  expressed in degrees counter‐
              clockwise starting from a left‐to‐right direction.  If the value
              is a number, it shall be one of: [1m0 [22m= Left to right, [1m90 [22m=  Bottom
              to  top  (Wipe only), [1m180 [22m= Right to left (Wipe only), [1m270 [22m= Top
              to bottom, [1m315 [22m= Top‐left to  bottom‐right  (Glitter  only)  The
              value can be [1mNone[22m, which is relevant only for the [1mFly [22mtransition
              when the value of [4mscale[24m is not 1.0.

              [4mscale[24m  (Optional; PDF 1.5; [1mFly [22mtransition style only) The start‐
              ing or ending scale at which the changes shall be drawn.  If [4mmo‐[0m
              [4mtion[24m specifies an inward transition, the scale  of  the  changes
              drawn  shall  progress  from [4mscale[24m to 1.0 over the course of the
              transition.  If [4mmotion[24m  specifies  an  outward  transition,  the
              scale of the changes drawn shall progress from 1.0 to [4mscale[24m over
              the course of the transition

              [4mbool[24m (Optional; PDF 1.5; [1mFly [22mtransition style only) If [1mtrue[22m, the
              area that shall be flown in is rectangular and opaque.

              This command can be used by calling the macro [1m.pdftransition [22mus‐
              ing  the  parameters described above.  Any of the parameters may
              be replaced with a "." which signifies the parameter retains its
              previous value, also any trailing  missing  parameters  are  ig‐
              nored.

              [1mNote: [22mnot all PDF Readers support any or all these transitions.

       [1m\X'pdf: background [4m[22mcmd[24m [4mleft[24m [4mtop[24m [4mright[24m [4mbottom[24m [4mweight[24m[1m'[0m
       [1m\X'pdf: background off'[0m
       [1m\X'pdf: background footnote [4m[22mbottom[24m[1m'[0m
              produces a background rectangle on the page, where

              [4mcmd[24m    is  the  command,  which can be any of “[1mpage[22m|[1mfill[22m|[1mbox[22m” in
                     combination.  Thus, “[1mpagefill[22m”  would  draw  a  rectangle
                     which  covers  the whole current page size (in which case
                     the rest of the parameters can be omitted because the box
                     dimensions are taken from the current media size).  “[1mbox‐[0m
                     [1mfill[22m”, on the other hand, requires the  given  dimensions
                     to  place  the box.  Including “[1mfill[22m” in the command will
                     paint the rectangle with the current fill colour (as with
                     [1m\M[][22m) and including “[1mbox[22m” will give the rectangle a  bor‐
                     der in the current stroke colour (as with [1m\m[][22m).

                     [4mcmd[24m  may  also  be “[1moff[22m” on its own, which will terminate
                     drawing the current box.  If you have  specified  a  page
                     colour with “[1mpagefill[22m”, it is always the first box in the
                     stack,  and  if you specify it again, it will replace the
                     first entry.  Be aware that the  “[1mpagefill[22m”  box  renders
                     the  page opaque, so tools that “watermark” PDF pages are
                     unlikely to be successful.  To return the  background  to
                     transparent,  issue  an “[1moff[22m” command with no other boxes
                     open.

                     Finally, [4mcmd[24m may be “[1mfootnote[22m” followed by  a  new  value
                     for  [4mbottom[24m, which will be used for all open boxes on the
                     current page.  This is to allow room for  footnote  areas
                     that  grow while a page is processed (to accommodate mul‐
                     tiple footnotes, for instance).  (If the value  is  nega‐
                     tive,  it  is  used  as  an offset from the bottom of the
                     page.)

              [4mleft[0m
              [4mtop[0m
              [4mright[0m
              [4mbottom[24m are the coordinates of the box.  The [4mtop[24m and [4mbottom[24m coor‐
                     dinates are the minimum and maximum for  the  box,  since
                     the  actual  start of the box is [4mgroff[24m’s drawing position
                     when you issue the command, and the bottom of the box  is
                     the point where you turn the box “[1moff[22m”.  The top and bot‐
                     tom  coordinates are used only if the box drawing extends
                     onto the next page; ordinarily, they would be set to  the
                     header and footer margins.

              [4mweight[24m provides  the  line  width for the border if “[1mbox[22m” is in‐
                     cluded in the command.

              The convenience macro for  this  escape  sequence  is  [1m.pdfback‐[0m
              [1mground[22m.    An   [4msboxes[24m   macro   file  is  also  available;  see
              [4mgroff_tmac[24m(5).

   [1mMacros[0m
       [4mgropdf[24m’s support macros in [4mpdf.tmac[24m define the convenience  macros  de‐
       scribed  above.   Some  features  have no direct device control command
       counterpart.

       [1m.pdfinfo /[4m[22mfield[24m [4mcontent[24m ...
              Define PDF metadata.  [4mfield[24m may be be one of [1mTitle[22m, [1mAuthor[22m, [1mSub‐[0m
              [1mject[22m, [1mKeywords[22m, or another datum supported by the  PDF  standard
              or your reader.  [4mfield[24m must be prefixed with a slash.

   [1mImporting graphics[0m
       [4mgropdf[24m  supports  only  the inclusion of other PDF files for inline im‐
       ages.  Such a PDF file may, however, contain any of the graphic formats
       supported by the PDF standard, such as JPEG/JFIF, PNG,  and  GIF.   Any
       application  that outputs PDF can thus be used to prepare files for em‐
       bedding in documents processed by [4mgroff[24m and [4mgropdf[24m.

       The PDF file you wish to insert must be a single page and  the  drawing
       must just fit inside the media size of the PDF file.  In [4minkscape[24m(1) or
       [4mgimp[24m(1), for example, make sure the canvas size just fits the image.

       The  PDF  parser  [4mgropdf[24m implements has not been rigorously tested with
       all applications that produce PDF.  If you find a single‐page PDF which
       fails to import properly, try processing it with the [4mpdftk[24m(1) program.
              pdftk [4mexisting‐file[24m output [4mnew‐file[0m
       You may find that [4mnew‐file[24m imports successfully.

   [1mTrueType and other font formats[0m
       [4mgropdf[24m does not yet support any font formats besides Adobe Type 1  (PFA
       or PFB).

[1mFont installation[0m
       The following is a step‐by‐step font installation guide for [4mgropdf.[0m

       • Convert  your  font  to something [4mgroff[24m understands.  This is a Post‐
         Script Type 1 font in PFA or PFB format, together with an  AFM  file.
         A PFA file begins as follows.
                %!PS-AdobeFont-1.0:
         A  PFB file contains this string as well, preceded by some non‐print‐
         ing bytes.  In the following steps,  we  will  consider  the  use  of
         CTAN’s    BrushScriptX‐Italic    ⟨https://ctan.org/tex-archive/fonts/
         brushscr⟩ font in PFA format.

       • Convert the AFM file to  a  [4mgroff[24m  font  description  file  with  the
         [4mafmtodit[24m(1) program.  For instance,
                $ [1mafmtodit BrushScriptX-Italic.afm text.map BSI[0m
         converts  the  Adobe  Font Metric file [4mBrushScriptX-Italic.afm[24m to the
         [4mgroff[24m font description file [4mBSI[24m.

         If you have a font family which  provides  regular  upright  (roman),
         bold,   italic,  and  bold‐italic  styles,  (where  “italic”  may  be
         “oblique” or “slanted”), we recommend using [1mR[22m, [1mB[22m, [1mI[22m, and [1mBI[22m,  respec‐
         tively,  as  suffixes to the [4mgroff[24m font family name to enable [4mgroff[24m’s
         font family and style selection  features.   An  example  is  [4mgroff[24m’s
         built‐in support for Times: the font family name is abbreviated as [1mT[22m,
         and  the  [4mgroff[24m font names are therefore [1mTR[22m, [1mTB[22m, [1mTI[22m, and [1mTBI[22m.  In our
         example, however, the BrushScriptX font  is  available  in  a  single
         style only, italic.

       • Install  the  [4mgroff[24m font description file(s) in a [4mdevpdf[24m subdirectory
         in the search path that [4mgroff[24m uses for device and font file  descrip‐
         tions.   See  the  [4mGROFF_FONT_PATH[24m  entry in section “Environment” of
         [4mtroff[24m(1) for the current value of the font search path.  While  [4mgroff[0m
         doesn’t  directly  use  AFM  files,  it  is a good idea to store them
         alongside its font description files.

       • Register fonts in the [4mdevpdf/download[24m file so they can be located for
         embedding in PDF files [4mgropdf[24m generates.   Only  the  first  [4mdownload[0m
         file  encountered in the font search path is read.  If in doubt, copy
         the default [4mdownload[24m file (see section “Files” below)  to  the  first
         directory  in  the  font  search  path and add your fonts there.  The
         PostScript font name used by [4mgropdf[24m is  stored  in  the  [1minternalname[0m
         field in the [4mgroff[24m font description file.  (This name does not neces‐
         sarily  resemble  the  font’s file name.)  If the font in our example
         had originated from a foundry named [1mZ[22m, we  would  add  the  following
         line to [4mdownload[24m.
                Z→BrushScriptX-Italic→BrushScriptX-Italic.pfa
         A  tab  character,  depicted as →, separates the fields.  The default
         foundry has no name: its field is empty and entries corresponding  to
         it start with a tab character, as will the one in our example.

       • Test the selection and embedding of the new font.
                printf "\\f[BSI]Hello, world!\n" | groff -T pdf -P -e >hello.pdf
                see hello.pdf

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              A  list  of directories in which to seek the selected output de‐
              vice’s directory of device and font description files.   If,  in
              the  [4mdownload[24m file, the font file has been specified with a full
              path,  no  directories   are   searched.    See   [4mtroff[24m(1)   and
              [4mgroff_font[24m(5).

       [4mGROPDF_NOSLIDE[0m
              If  set  and evaluates to a true value (to Perl), [4mgropdf[24m ignores
              commands specific to presentation PDFs, producing a  normal  PDF
              instead.

       [4mSOURCE_DATE_EPOCH[0m
              A  timestamp  (expressed as seconds since the Unix epoch) to use
              as the output creation timestamp in place of the  current  time.
              The  time  is  converted  to  human‐readable  form  using Perl’s
              [4mlocaltime()[24m function and recorded in a PDF comment.

       [4mTZ[24m     The time zone to use when converting the current time (or  value
              of [4mSOURCE_DATE_EPOCH[24m) to human‐readable form; see [4mtzset[24m(3).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devpdf/DESC[0m
              describes the [1mpdf [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devpdf/[24mF
              describes the font known as [4mF[24m on device [1mpdf[22m.

       [4m/usr/share/groff/1.23.0/font/devpdf/U-[24mF
              describes  the  font  from the URW foundry (versus the Adobe de‐
              fault) known as [4mF[24m on device [1mpdf[22m.

       [4m/usr/share/groff/1.23.0/font/devpdf/download[0m
              lists fonts available for embedding within the PDF document  (by
              analogy to the [1mps [22mdevice’s downloadable font support).

       [4m/usr/share/groff/1.23.0/font/devpdf/Foundry[0m
              is  a  data  file used by the [4mgroff[24m build system to locate Post‐
              Script Type 1 fonts.

       [4m/usr/share/groff/1.23.0/font/devpdf/enc/text.enc[0m
              describes the encoding scheme used by  most  PostScript  Type  1
              fonts;  the [1mencoding [22mdirective of font description files for the
              [1mpdf [22mdevice refers to it.

       [4m/usr/share/groff/1.23.0/tmac/pdf.tmac[0m
              defines macros for use with the [1mpdf [22moutput device.  It is  auto‐
              matically  loaded  by  [4mtroffrc[24m when the [1mpdf [22moutput device is se‐
              lected.

       [4m/usr/share/groff/1.23.0/tmac/pdfpic.tmac[0m
              defines the [1mPDFPIC [22mmacro for embedding images in a document; see
              [4mgroff_tmac[24m(5).  It is automatically loaded by [4mtroffrc.[0m

[1mAuthors[0m
       [4mgropdf[24m was written and is maintained  by  Deri  James  ⟨deri@chuzzlewit
       .myzen.co.uk⟩.

[1mSee also[0m
       [4m/usr/share/doc/groff-1.23.0/sboxes/msboxes.ms[0m
       [4m/usr/share/doc/groff-1.23.0/sboxes/msboxes.pdf[0m
              “Using PDF boxes with [4mgroff[24m and the [4mms[24m macros”, by Deri James.

       [4mpresent.tmac[0m
              is  part  of  [4mgpresent[24m  ⟨https://bob.diertens.org/corner/useful/
              gpresent/⟩, a software package by Bob Diertens that  works  with
              [4mgroff[24m to produce presentations (“foils”, or “slide decks”).

       [4mafmtodit[24m(1), [4mgroff[24m(1), [4mtroff[24m(1), [4mgroff_font[24m(5), [4mgroff_out[24m(5)

groff 1.23.0                      5 July 2023                        [4mgropdf[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrops[24m(1)                    General Commands Manual                   [4mgrops[24m(1)

[1mName[0m
       grops - [4mgroff[24m output driver for PostScript

[1mSynopsis[0m
       [1mgrops [22m[[1m-glm[22m] [[1m-b [4m[22mbrokenness‐flags[24m] [[1m-c [4m[22mnum‐copies[24m] [[1m-F [4m[22mfont‐directory[24m]
             [[1m-I [4m[22minclusion‐directory[24m] [[1m-p [4m[22mpaper‐format[24m] [[1m-P [4m[22mprologue‐file[24m]
             [[1m-w [4m[22mrule‐thickness[24m] [[4mfile[24m ...]

       [1mgrops --help[0m

       [1mgrops -v[0m
       [1mgrops --version[0m

[1mDescription[0m
       The GNU [4mroff[24m PostScript output driver translates the output of [4mtroff[24m(1)
       into  PostScript.  Normally, [4mgrops[24m is invoked by [4mgroff[24m(1) when the lat‐
       ter is given the “[1m-T ps[22m” option.  (In this installation, [1mps [22mis the  de‐
       fault  output device.)  Use [4mgroff[24m’s [1m-P [22moption to pass any options shown
       above to [4mgrops[24m.  If no [4mfile[24m arguments are given, or  if  [4mfile[24m  is  “-”,
       [4mgrotty[24m reads the standard input stream.  Output is written to the stan‐
       dard output stream.

       When called with multiple [4mfile[24m arguments, [4mgrops[24m doesn’t produce a valid
       document  structure (one conforming to the Document Structuring Conven‐
       tions).  To print such concatenated output, it is necessary to  deacti‐
       vate DSC handling in the printing program or previewer.

       See  section  “Font installation” below for a guide to installing fonts
       for [4mgrops[24m.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-b [4m[22mn[24m   Work around problems with spoolers, previewers, and older print‐
              ers.     Normally,   [4mgrops[24m   produces   output   at   PostScript
              LanguageLevel 2 that conforms to version  3.0  of  the  Document
              Structuring Conventions.  Some software and devices can’t handle
              such  a  data stream.  The value of [4mn[24m determines what [4mgrops[24m does
              to make its output acceptable to such consumers.   If  [4mn[24m  is  [1m0[22m,
              [4mgrops[24m  employs  no  workarounds, which is the default; it can be
              changed by modifying the [1mbroken [22mdirective in [4mgrops[24m’s [4mDESC[24m file.

              Add 1 to suppress generation of [1m%%BeginDocumentSetup [22mand  [1m%%End‐[0m
              [1mDocumentSetup  [22mcomments;  this  is  needed for early versions of
              TranScript that get confused by anything between the [1m%%EndProlog[0m
              comment and the first [1m%%Page [22mcomment.

              Add 2 to omit lines in included files beginning with  [1m%![22m,  which
              confuse Sun’s [4mpageview[24m previewer.

              Add  4  to  omit  lines in included files beginning with [1m%%Page[22m,
              [1m%%Trailer [22mand [1m%%EndProlog[22m; this  is  needed  for  spoolers  that
              don’t understand [1m%%BeginDocument [22mand [1m%%EndDocument [22mcomments.

              Add  8 to write [1m%!PS-Adobe-2.0 [22mrather than [1m%!PS-Adobe-3.0 [22mas the
              first line of the PostScript output; this is needed  when  using
              Sun’s Newsprint with a printer that requires page reversal.

              Add 16 to omit media size information (that is, output neither a
              [1m%%DocumentMedia  [22mcomment  nor  the [1msetpagedevice [22mPostScript com‐
              mand).  This was the behavior of [4mgroff[24m 1.18.1 and earlier; it is
              needed for  older  printers  that  don’t  understand  PostScript
              LanguageLevel  2, and is also necessary if the output is further
              processed to produce an EPS file; see  subsection  “Escapsulated
              PostScript” below.

       [1m-c [4m[22mn[24m   Output [4mn[24m copies of each page.

       [1m-F [4m[22mdir[24m Prepend  directory  dir[4m/dev[24mname  to the search path for font and
              device description and PostScript prologue files;  [4mname[24m  is  the
              name of the device, usually [1mps[22m.

       [1m-g     [22mGenerate PostScript code to guess the page length.  The guess is
              correct only if the imageable area is vertically centered on the
              page.   This option allows you to generate documents that can be
              printed on both U.S. letter and A4 paper formats without change.

       [1m-I [4m[22mdir[24m Search the directory [4mdir[24m for files named  in  [1m\X'ps:  file'  [22mand
              [1m\X'ps:  import' [22mescape sequences.  [1m-I [22mmay be specified more than
              once; each [4mdir[24m is searched in the given order.   To  search  the
              current  working  directory before others, add “[1m-I .[22m” at the de‐
              sired place; it is otherwise searched last.

       [1m-l     [22mUse landscape orientation rather than portrait.

       [1m-m     [22mTurn on manual feed for the document.

       [1m-p [4m[22mfmt[24m Set  physical  dimensions  of  output  medium,  overriding   the
              [1mpapersize[22m,  [1mpaperlength[22m,  and  [1mpaperwidth [22mdirectives in the [4mDESC[0m
              file.  [4mfmt[24m can be any argument accepted by the [1mpapersize  [22mdirec‐
              tive; see [4mgroff_font[24m(5).

       [1m-P [4m[22mprologue[0m
              Use  the file [4mprologue[24m, sought in the [4mgroff[24m font search path, as
              the PostScript prologue, overriding  the  default  (see  section
              “Files” below) and the environment variable [4mGROPS_PROLOGUE.[0m

       [1m-w [4m[22mn[24m   Draw  rules  (lines) with a thickness of [4mn[24m thousandths of an em.
              The default thickness is [1m40 [22m(0.04 em).

[1mUsage[0m
       The input to [4mgrops[24m must be in the format output by [4mtroff[24m(1),  described
       in  [4mgroff_out[24m(5).   In  addition, the device and font description files
       for the device used must meet certain requirements.  The device resolu‐
       tion must be an integer multiple of 72 times the [1msizescale[22m.  The device
       description file must contain a valid paper format; see  [4mgroff_font[24m(5).
       Each font description file must contain a directive
              internalname [4mpsname[0m
       which says that the PostScript name of the font is [4mpsname[24m.

       A font description file may also contain a directive
              encoding [4menc‐file[0m
       which  says  that the PostScript font should be reencoded using the en‐
       coding described in [4menc‐file[24m; this file should consist of a sequence of
       lines of the form
              [4mpschar[24m [4mcode[0m
       where [4mpschar[24m is the PostScript name of the character, and [4mcode[24m  is  its
       position  in  the encoding expressed as a decimal integer; valid values
       are in the range 0 to 255.  Lines starting with [1m# [22mand blank  lines  are
       ignored.   The  code  for  each character given in the font description
       file must correspond to the code for the character in encoding file, or
       to the code in the default encoding for the font if the PostScript font
       is not to be reencoded.  This code can be used with the [1m\N  [22mescape  se‐
       quence  in  [4mtroff[24m  to  select the character, even if it does not have a
       [4mgroff[24m glyph name.  Every character in the font  description  file  must
       exist in the PostScript font, and the widths given in the font descrip‐
       tion file must match the widths used in the PostScript font.  [4mgrops[24m as‐
       sumes  that  a  character with a [4mgroff[24m name of [1mspace [22mis blank (makes no
       marks on the page); it can make use of such  a  character  to  generate
       more efficient and compact PostScript output.

       [4mgrops[24m  is  able  to  display all glyphs in a PostScript font; it is not
       limited to 256 of them.  [4menc‐file[24m (or the default encoding if no encod‐
       ing file is specified) just defines the order of glyphs for  the  first
       256  characters; all other glyphs are accessed with additional encoding
       vectors which [4mgrops[24m produces on the fly.

       [4mgrops[24m can embed fonts in a document that are necessary  to  render  it;
       this  is  called “downloading”.  Such fonts must be in PFA format.  Use
       [4mpfbtops[24m(1) to convert a Type 1 font in PFB format.  Downloadable  fonts
       must be listed a [4mdownload[24m file containing lines of the form
              [4mpsname[24m [4mfile[0m
       where  [4mpsname[24m  is the PostScript name of the font, and [4mfile[24m is the name
       of the file containing it; lines beginning with [1m# [22mand blank  lines  are
       ignored; fields may be separated by tabs or spaces.  [4mfile[24m is sought us‐
       ing  the  same mechanism as that for [4mgroff[24m font description files.  The
       [4mdownload[24m file itself is also sought using  this  mechanism;  currently,
       only  the  first matching file found in the device and font description
       search path is used.

       If the file containing a downloadable font or  imported  document  con‐
       forms  to the Adobe Document Structuring Conventions, then [4mgrops[24m inter‐
       prets any comments in the files sufficiently to  ensure  that  its  own
       output  is conforming.  It also supplies any needed font resources that
       are listed in the [4mdownload[24m file as well as any needed  file  resources.
       It  is  also  able to handle inter‐resource dependencies.  For example,
       suppose that you have a downloadable font called Garamond, and  also  a
       downloadable  font  called  Garamond‐Outline  which depends on Garamond
       (typically it would be defined to copy Garamond’s font dictionary,  and
       change  the PaintType), then it is necessary for Garamond to appear be‐
       fore Garamond‐Outline in the PostScript document.  [4mgrops[24m  handles  this
       automatically  provided  that  the downloadable font file for Garamond‐
       Outline indicates its dependence on Garamond by means of  the  Document
       Structuring  Conventions,  for  example by beginning with the following
       lines.
              %!PS-Adobe-3.0 Resource-Font
              %%DocumentNeededResources: font Garamond
              %%EndComments
              %%IncludeResource: font Garamond
       In this case, both Garamond  and  Garamond‐Outline  would  need  to  be
       listed  in  the  [4mdownload[24m file.  A downloadable font should not include
       its own name in a [1m%%DocumentSuppliedResources [22mcomment.

       [4mgrops[24m does not interpret  [1m%%DocumentFonts  [22mcomments.   The  [1m%%Document‐[0m
       [1mNeededResources[22m,     [1m%%DocumentSuppliedResources[22m,    [1m%%IncludeResource[22m,
       [1m%%BeginResource[22m,  and  [1m%%EndResource  [22mcomments  (or  possibly  the  old
       [1m%%DocumentNeededFonts[22m, [1m%%DocumentSuppliedFonts[22m, [1m%%IncludeFont[22m, [1m%%Begin‐[0m
       [1mFont[22m, and [1m%%EndFont [22mcomments) should be used.

       The  default stroke and fill color is black.  For colors defined in the
       “rgb” color space, [1msetrgbcolor [22mis used; for “cmy” and “cmyk”,  [1msetcmyk‐[0m
       [1mcolor[22m;   and   for  “gray”,  [1msetgray[22m.   [1msetcmykcolor  [22mis  a  PostScript
       LanguageLevel 2 command and thus not available on some older printers.

   [1mTypefaces[0m
       Styles called [1mR[22m, [1mI[22m, [1mB[22m, and [1mBI [22mmounted at font positions 1 to  4.   Text
       fonts are grouped into families [1mA[22m, [1mBM[22m, [1mC[22m, [1mH[22m, [1mHN[22m, [1mN[22m, [1mP[22m, and [1mT[22m, each hav‐
       ing members in each of these styles.

              [1mAR     [22mAvantGarde‐Book
              [1mAI     [22mAvantGarde‐BookOblique
              [1mAB     [22mAvantGarde‐Demi
              [1mABI    [22mAvantGarde‐DemiOblique
              [1mBMR    [22mBookman‐Light
              [1mBMI    [22mBookman‐LightItalic
              [1mBMB    [22mBookman‐Demi
              [1mBMBI   [22mBookman‐DemiItalic
              [1mCR     [22mCourier
              [1mCI     [22mCourier‐Oblique
              [1mCB     [22mCourier‐Bold
              [1mCBI    [22mCourier‐BoldOblique
              [1mHR     [22mHelvetica
              [1mHI     [22mHelvetica‐Oblique
              [1mHB     [22mHelvetica‐Bold
              [1mHBI    [22mHelvetica‐BoldOblique
              [1mHNR    [22mHelvetica‐Narrow
              [1mHNI    [22mHelvetica‐Narrow‐Oblique
              [1mHNB    [22mHelvetica‐Narrow‐Bold
              [1mHNBI   [22mHelvetica‐Narrow‐BoldOblique
              [1mNR     [22mNewCenturySchlbk‐Roman
              [1mNI     [22mNewCenturySchlbk‐Italic
              [1mNB     [22mNewCenturySchlbk‐Bold
              [1mNBI    [22mNewCenturySchlbk‐BoldItalic
              [1mPR     [22mPalatino‐Roman
              [1mPI     [22mPalatino‐Italic
              [1mPB     [22mPalatino‐Bold
              [1mPBI    [22mPalatino‐BoldItalic
              [1mTR     [22mTimes‐Roman
              [1mTI     [22mTimes‐Italic
              [1mTB     [22mTimes‐Bold
              [1mTBI    [22mTimes‐BoldItalic

       Another text font is not a member of a family.

              [1mZCMI   [22mZapfChancery‐MediumItalic

       Special fonts include [1mS[22m, the PostScript Symbol font; [1mZD[22m, Zapf Dingbats;
       [1mSS  [22m(slanted  symbol),  which contains oblique forms of lowercase Greek
       letters derived from Symbol; [1mEURO[22m, which offers a Euro  glyph  for  use
       with  old  devices lacking it; and [1mZDR[22m, a reversed version of ZapfDing‐
       bats (with symbols flipped about the vertical axis).   Most  glyphs  in
       these  fonts are unnamed and must be accessed using [1m\N[22m.  The last three
       are not standard PostScript fonts, but supplied by [4mgroff[24m and  therefore
       included in the default [4mdownload[24m file.

   [1mDevice control commands[0m
       [4mgrops[24m  recognizes device control commands produced by the [1m\X [22mescape se‐
       quence, but interprets only those that begin with a “[1mps:[22m” tag.

       [1m\X'ps: exec [4m[22mcode[24m[1m'[0m
              Execute the arbitrary PostScript commands [4mcode[24m.  The  PostScript
              [4mcurrentpoint[24m  is  set  to the [4mgroff[24m drawing position when the [1m\X[0m
              escape sequence is interpreted before executing [4mcode[24m.  The  ori‐
              gin  is  at  the  top left corner of the page; [4mx[24m coordinates in‐
              crease to the right, and [4my[24m coordinates down the page.  A  proce‐
              dure [1mu [22mis defined that converts [4mgroff[24m basic units to the coordi‐
              nate  system  in  effect  (provided  the user doesn’t change the
              scale).  For example,
                     .nr x 1i
                     \X'ps: exec \nx u 0 rlineto stroke'
              draws a horizontal line one inch long.  [4mcode[24m may make changes to
              the graphics state, but any changes persist only to the  end  of
              the  page.  A dictionary containing the definitions specified by
              the [1mdef [22mand [1mmdef [22mcommands is on top of the dictionary stack.  If
              your code adds definitions to this dictionary, you should  allo‐
              cate  space  for  them  using “[1m\X'ps: mdef [4m[22mn[24m[1m'[22m”.  Any definitions
              persist only until the end of the page.  If you use the  [1m\Y  [22mes‐
              cape  sequence with an argument that names a macro, [4mcode[24m can ex‐
              tend over multiple lines.  For example,
                     .nr x 1i
                     .de y
                     ps: exec
                     \nx u 0 rlineto
                     stroke
                     ..
                     \Yy
              is another way to draw a horizontal line  one  inch  long.   The
              single  backslash  before “[1mnx[22m”—the only reason to use a register
              while defining the macro “[1my[22m”—is to convert a user‐specified  di‐
              mension “[1m1i[22m” to [4mgroff[24m basic units which are in turn converted to
              PostScript units with the [1mu [22mprocedure.

              [4mgrops[24m  wraps  user‐specified  PostScript code into a dictionary,
              nothing more.  In particular, it doesn’t start and end  the  in‐
              serted  code  with [1msave [22mand [1mrestore[22m, respectively.  This must be
              supplied by the user, if necessary.

       [1m\X'ps: file [4m[22mname[24m[1m'[0m
              This is the same as the [1mexec [22mcommand except that the  PostScript
              code is read from file [4mname[24m.

       [1m\X'ps: def [4m[22mcode[24m[1m'[0m
              Place a PostScript definition contained in [4mcode[24m in the prologue.
              There should be at most one definition per [1m\X [22mcommand.  Long de‐
              finitions  can  be  split over several [1m\X [22mcommands; all the [4mcode[0m
              arguments are simply joined together separated by newlines.  The
              definitions are placed in a dictionary  which  is  automatically
              pushed on the dictionary stack when an [1mexec [22mcommand is executed.
              If  you use the [1m\Y [22mescape sequence with an argument that names a
              macro, [4mcode[24m can extend over multiple lines.

       [1m\X'ps: mdef [4m[22mn[24m [4mcode[24m[1m'[0m
              Like [1mdef[22m, except that [4mcode[24m may  contain  up  to  [4mn[24m  definitions.
              [4mgrops[24m  needs  to know how many definitions [4mcode[24m contains so that
              it can create an appropriately sized  PostScript  dictionary  to
              contain them.

       [1m\X'ps: import [4m[22mfile[24m [4mllx[24m [4mlly[24m [4murx[24m [4mury[24m [4mwidth[24m [[4mheight[24m][1m'[0m
              Import  a PostScript graphic from [4mfile[24m.  The arguments [4mllx[24m, [4mlly[24m,
              [4murx[24m, and [4mury[24m give the bounding box of the graphic in the default
              PostScript coordinate system.  They should all be integers:  [4mllx[0m
              and  [4mlly[24m are the [4mx[24m and [4my[24m coordinates of the lower left corner of
              the graphic; [4murx[24m and [4mury[24m are the [4mx[24m and [4my[24m coordinates of the  up‐
              per  right  corner of the graphic; [4mwidth[24m and [4mheight[24m are integers
              that give the desired width and height in [4mgroff[24m basic  units  of
              the graphic.

              The  graphic  is scaled so that it has this width and height and
              translated so that the lower left corner of the graphic  is  lo‐
              cated at the position associated with [1m\X [22mcommand.  If the height
              argument  is  omitted it is scaled uniformly in the [4mx[24m and [4my[24m axes
              so that it has the specified width.

              The contents of the [1m\X [22mcommand are not interpreted by [4mtroff[24m,  so
              vertical  space  for the graphic is not automatically added, and
              the [4mwidth[24m and [4mheight[24m arguments are not allowed to have  attached
              scaling indicators.

              If  the  PostScript file complies with the Adobe Document Struc‐
              turing Conventions and contains a  [1m%%BoundingBox  [22mcomment,  then
              the  bounding  box  can  be  automatically extracted from within
              [4mgroff[24m input by using the [1mpsbb [22mrequest.

              See [4mgroff_tmac[24m(5) for a description of  the  [1mPSPIC  [22mmacro  which
              provides  a  convenient  high‐level  interface  for inclusion of
              PostScript graphics.

       [1m\X'ps: invis'[0m
       [1m\X'ps: endinvis'[0m
              No output is generated for text and drawing  commands  that  are
              bracketed  with  these [1m\X [22mcommands.  These commands are intended
              for use  when  output  from  [4mtroff[24m  is  previewed  before  being
              processed with [4mgrops[24m; if the previewer is unable to display cer‐
              tain characters or other constructs, then other substitute char‐
              acters  or  constructs  can be used for previewing by bracketing
              them with these [1m\X [22mcommands.

              For example, [4mgxditview[24m is not able to  display  a  proper  [1m\[em][0m
              character because the standard X11 fonts do not provide it; this
              problem can be overcome by executing the following request

                     .char \[em] \X'ps: invis'\
                     \Z'\v'‐.25m'\h'.05m'\D'l .9m 0'\h'.05m''\
                     \X'ps: endinvis'\[em]

              In this case, [4mgxditview[24m is unable to display the [1m\[em] [22mcharacter
              and draws the line, whereas [4mgrops[24m prints the [1m\[em] [22mcharacter and
              ignores  the  line (this code is already in file [4mXps.tmac[24m, which
              is loaded if a document intended for  [4mgrops[24m  is  previewed  with
              [4mgxditview[24m).

       If  a  PostScript  procedure [1mBPhook [22mhas been defined via a “[1mps: def[22m” or
       “[1mps: mdef[22m” device control command, it is executed at the  beginning  of
       every  page  (before anything is drawn or written by [4mgroff[24m).  For exam‐
       ple, to underlay the page contents with the word “DRAFT” in light gray,
       you might use

              .de XX
              ps: def
              /BPhook
              { gsave .9 setgray clippath pathbbox exch 2 copy
                .5 mul exch .5 mul translate atan rotate pop pop
                /NewCenturySchlbk‐Roman findfont 200 scalefont setfont
                (DRAFT) dup stringwidth pop -.5 mul -70 moveto show
                grestore }
              def
              ..
              .devicem XX

       Or, to cause lines and polygons to be drawn with  square  linecaps  and
       mitered  linejoins instead of the round linecaps and linejoins normally
       used by [4mgrops[24m, use
              .de XX
              ps: def
              /BPhook { 2 setlinecap 0 setlinejoin } def
              ..
              .devicem XX
       (square linecaps, as opposed to butt linecaps  (“[1m0  setlinecap[22m”),  give
       true  corners  in  boxed  tables even though the lines are drawn uncon‐
       nected).

   [1mEncapsulated PostScript[0m
       [4mgrops[24m itself doesn’t emit  bounding  box  information.   The  following
       script, [4mgroff2eps[24m, produces an EPS file.

              #! /bin/sh
              groff -P-b16 "$1" > "$1".ps
              gs -dNOPAUSE -sDEVICE=bbox -- "$1".ps 2> "$1".bbox
              sed -e "/^%%Orientation/r $1.bbox" \
                  -e "/^%!PS-Adobe-3.0/s/$/ EPSF-3.0/" "$1".ps > "$1".eps
              rm "$1".ps "$1".bbox

       You can then use “[1mgroff2eps foo[22m” to convert file [4mfoo[24m to [4mfoo.eps[24m.

   [1mTrueType and other font formats[0m
       TrueType  fonts  can  be  used with [4mgrops[24m if converted first to Type 42
       format, a PostScript wrapper equivalent to the PFA format described  in
       [4mpfbtops[24m(1).   Several methods exist to generate a Type 42 wrapper; some
       of them involve the use of a  PostScript  interpreter  such  as  Ghost‐
       script—see [4mgs[24m(1).

       One  approach is to use FontForge ⟨https://fontforge.org/⟩, a font edi‐
       tor that can convert most outline font formats.  Here’s an  example  of
       using  the  Roboto  Slab  Serif font with [4mgroff[24m.  Several variables are
       used so that you can more easily adapt it into your own script.

           MAP=/usr/share/groff/1.23.0/font/devps/generate/text.map
           TTF=/usr/share/fonts/truetype/roboto/slab/RobotoSlab-Regular.ttf
           BASE=$(basename "$TTF")
           INT=${BASE%.ttf}
           PFA=$INT.pfa
           AFM=$INT.afm
           GFN=RSR
           DIR=$HOME/.local/groff/font
           mkdir -p "$DIR"/devps
           fontforge -lang=ff -c "Open(\"$TTF\");\
           Generate(\"$DIR/devps/$PFA\");"
           afmtodit "$DIR/devps/$AFM" "$MAP" "$DIR/devps/$GFN"
           printf "$BASE\t$PFA\n" >> "$DIR/devps/download"

       [4mfontforge[24m and [4mafmtodit[24m may generate warnings depending on  the  attrib‐
       utes of the font.  The test procedure is simple.

           printf ".ft RSR\nHello, world!\n" | groff -F "$DIR" > hello.ps

       Once you’re satisfied that the font works, you may want to generate any
       available  related  styles  (for instance, Roboto Slab also has “Bold”,
       “Light”, and “Thin” styles) and set up [4mGROFF_FONT_PATH[24m in your environ‐
       ment to include the directory you keep the generated fonts in  so  that
       you don’t have to use the [1m-F [22moption.

[1mFont installation[0m
       The following is a step‐by‐step font installation guide for [4mgrops.[0m

       • Convert  your  font  to something [4mgroff[24m understands.  This is a Post‐
         Script Type 1 font in PFA format or a PostScript Type  42  font,  to‐
         gether with an AFM file.  A PFA file begins as follows.
                %!PS-AdobeFont-1.0:
         A  PFB file contains this string as well, preceded by some non‐print‐
         ing bytes.  If your font is in PFB  format,  use  [4mgroff[24m’s  [4mpfbtops[24m(1)
         program  to  convert it to PFA.  For TrueType and other font formats,
         we recommend [4mfontforge[24m, which can convert most outline font  formats.
         A Type 42 font file begins as follows.
                %!PS-TrueTypeFont
         This is a wrapper format for TrueType fonts.  Old PostScript printers
         might not support them (that is, they might not have a built‐in True‐
         Type font interpreter).  In the following steps, we will consider the
         use   of  CTAN’s  BrushScriptX‐Italic  ⟨https://ctan.org/tex-archive/
         fonts/brushscr⟩ font in PFA format.

       • Convert the AFM file to  a  [4mgroff[24m  font  description  file  with  the
         [4mafmtodit[24m(1) program.  For instance,
                $ [1mafmtodit BrushScriptX-Italic.afm text.map BSI[0m
         converts  the  Adobe  Font Metric file [4mBrushScriptX-Italic.afm[24m to the
         [4mgroff[24m font description file [4mBSI[24m.

         If you have a font family which  provides  regular  upright  (roman),
         bold, italic, and bold‐italic styles (where “italic” may be “oblique”
         or  “slanted”),  we  recommend using the letters [1mR[22m, [1mB[22m, [1mI[22m, and [1mBI[22m, re‐
         spectively, as suffixes to the  [4mgroff[24m  font  family  name  to  enable
         [4mgroff[24m’s  font  family  and  style  selection features.  An example is
         [4mgroff[24m’s built‐in support for Times: the font family name is  abbrevi‐
         ated  as  [1mT[22m,  and  the [4mgroff[24m font names are therefore [1mTR[22m, [1mTB[22m, [1mTI[22m, and
         [1mTBI[22m.  In our example, however, the BrushScriptX font is available  in
         a single style only, italic.

       • Install the [4mgroff[24m font description file(s) in a [4mdevps[24m subdirectory in
         the  search  path  that  [4mgroff[24m uses for device and font file descrip‐
         tions.  See the [4mGROFF_FONT_PATH[24m entry  in  section  “Environment”  of
         [4mtroff[24m(1)  for the current value of the font search path.  While [4mgroff[0m
         doesn’t directly use AFM files, it is  a  good  idea  to  store  them
         alongside its font description files.

       • Register  fonts in the [4mdevps/download[24m file so they can be located for
         embedding in PostScript files [4mgrops[24m generates.  Only the first  [4mdown‐[0m
         [4mload[24m  file encountered in the font search path is read.  If in doubt,
         copy the default [4mdownload[24m file (see section  “Files”  below)  to  the
         first  directory  in  the  font search path and add your fonts there.
         The PostScript font name used by [4mgrops[24m is stored in the  [1minternalname[0m
         field in the [4mgroff[24m font description file.  (This name does not neces‐
         sarily  resemble the font’s file name.)  We add the following line to
         [4mdownload[24m.
                BrushScriptX-Italic→BrushScriptX-Italic.pfa
         A tab character, depicted as →, separates the fields.

       • Test the selection and embedding of the new font.
                printf "\\f[BSI]Hello, world!\n" | groff -T ps -P -e >hello.ps
                see hello.pdf

[1mOld fonts[0m
       [4mgroff[24m versions 1.19.2 and earlier contained descriptions of a  slightly
       different set of the base 35 PostScript level 2 fonts defined by Adobe.
       The  older  set  has  229 glyphs and a larger set of kerning pairs; the
       newer one has 314 glyphs and includes the Euro  glyph.   For  backwards
       compatibility,  these  old  font descriptions are also installed in the
       [4m/usr/share/groff/1.23.0/oldfont/devps[24m directory.

       To use them, make sure that [4mgrops[24m finds the fonts  before  the  default
       system  fonts  (with the same names): either give [4mgrops[24m the [1m-F [22mcommand‐
       line option,
              $ [1mgroff -Tps -P-F -P/usr/share/groff/1.23.0/oldfont [22m...
       or add the directory to [4mgroff[24m’s font and device description search path
       environment variable,
              $ [1mGROFF_FONT_PATH=/usr/share/groff/1.23.0/oldfont \[0m
                     [1mgroff -Tps [22m...
       when the command runs.

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              A list of directories in which to seek the selected  output  de‐
              vice’s  directory  of  device  and  font description files.  See
              [4mtroff[24m(1) and [4mgroff_font[24m(5).

       [4mGROPS_PROLOGUE[0m
              If this is set to [4mfoo[24m, then [4mgrops[24m uses the file [4mfoo[24m (in the font
              path) instead of the default prologue file [4mprologue[24m.  The option
              [1m-P [22moverrides this environment variable.

       [4mSOURCE_DATE_EPOCH[0m
              A timestamp (expressed as seconds since the Unix epoch)  to  use
              as  the  output creation timestamp in place of the current time.
              The time is converted to human‐readable form using [4mctime[24m(3)  and
              recorded in a PostScript comment.

       [4mTZ[24m     The  time zone to use when converting the current time (or value
              of [4mSOURCE_DATE_EPOCH[24m) to human‐readable form; see [4mtzset[24m(3).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devps/DESC[0m
              describes the [1mps [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devps/[24mF
              describes the font known as [4mF[24m on device [1mps[22m.

       [4m/usr/share/groff/1.23.0/font/devps/download[0m
              lists fonts available for embedding within the PostScript  docu‐
              ment (or download to the device).

       [4m/usr/share/groff/1.23.0/font/devps/prologue[0m
              is  the  default  PostScript  prologue  prefixed to every output
              file.

       [4m/usr/share/groff/1.23.0/font/devps/text.enc[0m
              describes the encoding scheme used by  most  PostScript  Type  1
              fonts;  the [1mencoding [22mdirective of font description files for the
              [1mps [22mdevice refers to it.

       [4m/usr/share/groff/1.23.0/tmac/ps.tmac[0m
              defines macros for use with the [1mps [22moutput device.  It  is  auto‐
              matically  loaded  by  [4mtroffrc[24m  when the [1mps [22moutput device is se‐
              lected.

       [4m/usr/share/groff/1.23.0/tmac/pspic.tmac[0m
              defines the [1mPSPIC [22mmacro for embedding images in a document;  see
              [4mgroff_tmac[24m(5).  It is automatically loaded by [4mtroffrc.[0m

       [4m/usr/share/groff/1.23.0/tmac/psold.tmac[0m
              provides  replacement  glyphs  for text fonts that lack complete
              coverage of the ISO Latin‐1 character set; using it,  [4mgroff[24m  can
              produce  glyphs like eth (ð) and thorn (þ) that older PostScript
              printers do not natively support.

       [4mgrops[24m creates temporary files using  the  template  “[4mgrops[24mXXXXXX”;  see
       [4mgroff[24m(1) for details on their storage location.

[1mSee also[0m
       PostScript  Language  Document  Structuring  Conventions  Specification
       ⟨http://partners.adobe.com/public/developer/en/ps/5001.DSC_Spec.pdf⟩

       [4mafmtodit[24m(1),    [4mgroff[24m(1),    [4mtroff[24m(1),    [4mpfbtops[24m(1),    [4mgroff_char[24m(7),
       [4mgroff_font[24m(5), [4mgroff_out[24m(5), [4mgroff_tmac[24m(5)

groff 1.23.0                      5 July 2023                         [4mgrops[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgrotty[24m(1)                   General Commands Manual                  [4mgrotty[24m(1)

[1mName[0m
       grotty - [4mgroff[24m output driver for typewriter‐like (terminal) devices

[1mSynopsis[0m
       [1mgrotty [22m[[1m-dfho[22m] [[1m-i[22m|[1m-r[22m] [[1m-F [4m[22mdir[24m] [[4mfile[24m ...]

       [1mgrotty -c [22m[[1m-bBdfhouU[22m] [[1m-F [4m[22mdir[24m] [[4mfile[24m ...]

       [1mgrotty --help[0m

       [1mgrotty -v[0m
       [1mgrotty --version[0m

[1mDescription[0m
       The  GNU  [4mroff[24m  TTY (“Teletype”) output driver translates the output of
       [4mtroff[24m(1) into a form suitable for  typewriter‐like  devices,  including
       terminal  emulators.   Normally, [4mgrotty[24m is invoked by [4mgroff[24m(1) when the
       latter is given one of  the  “[1m-T  ascii[22m”,  “[1m-T  latin1[22m”,  [1m-Tlatin1[22m,  or
       “[1m-T utf8[22m” options on systems using ISO character encoding standards, or
       with  “[1m-T cp1047[22m” or “[1m-T utf8[22m” on EBCDIC‐based hosts.  (In this instal‐
       lation, [1mps [22mis the default output device.)  Use  [4mgroff[24m’s  [1m-P  [22moption  to
       pass  any  options  shown  above  to  [4mgrotty[24m.  If no [4mfile[24m arguments are
       given, or if [4mfile[24m is “-”, [4mgrotty[24m reads the standard input stream.  Out‐
       put is written to the standard output stream.

       By default, [4mgrotty[24m emits SGR escape sequences (from ISO 6429, popularly
       called “ANSI escapes”) to change text attributes (bold, italic,  under‐
       line, reverse video [“negative image”] and colors).  Devices supporting
       the appropriate sequences can view [4mroff[24m documents using eight different
       background  and  foreground  colors.  Following ISO 6429, the following
       colors are defined in [4mtty.tmac[24m: black, white, red, green, blue, yellow,
       magenta, and cyan.  Unrecognized  colors  are  mapped  to  the  default
       color,  which  is dependent on the settings of the terminal.  OSC 8 hy‐
       perlinks are produced for these devices.

       In keeping with long‐standing practice and the rarity of terminals (and
       emulators) that support oblique or italic  fonts,  italicized  text  is
       represented with underlining by default—but see the [1m-i [22moption below.

   [1mSGR and OSC support in pagers[0m
       When  paging  [4mgrotty[24m’s  output with [4mless[24m(1), the latter program must be
       instructed to pass SGR and OSC sequences through to the device; its  [1m-R[0m
       option  is  one  way  to achieve this ([4mless[24m version 566 or later is re‐
       quired for OSC 8 support).  Consequently,  programs  like  [4mman[24m(1)  that
       page [4mroff[24m documents with [4mless[24m must call it with an appropriate option.

   [1mLegacy output format[0m
       The  [1m-c [22moption tells [4mgrotty[24m to use an output format compatible with pa‐
       per terminals, like the Teletype machines for which [4mroff[24m and [4mnroff[24m were
       first developed but which are no longer in wide use.   SGR  escape  se‐
       quences  are  not  emitted; bold, italic, and underlining character at‐
       tributes are thus not manipulated.  Instead, [4mgrotty[24m overstrikes, repre‐
       senting a bold character [4mc[24m with the sequence “[4mc[24m BACKSPACE [4mc[24m”, an italic
       character [4mc[24m with the sequence “[1m_ [22mBACKSPACE [4mc[24m”, and  bold  italics  with
       “[1m_  [22mBACKSPACE  [4mc[24m  BACKSPACE [4mc[24m”.  This rendering is inherently ambiguous
       when the character [4mc[24m is itself the underscore.

       The legacy output format can be rendered on a video terminal (or emula‐
       tor) by piping [4mgrotty[24m’s output through [4mul[24m(1),  which  may  render  bold
       italics  as  reverse  video.   Some implementations of [4mmore[24m(1) are also
       able to display these sequences; you may wish to experiment  with  that
       command’s  [1m-b [22moption.  [4mless[24m renders legacy bold and italics without re‐
       quiring options.  In contrast to the terminal output  drivers  of  some
       other  [4mroff[24m  implementations,  [4mgrotty[24m never outputs reverse line feeds.
       There is therefore no need to filter its output through [4mcol[24m(1).

   [1mDevice control commands[0m
       [4mgrotty[24m understands one device control function produced by the [4mroff[24m  [1m\X[0m
       escape sequence in a document.

       [1m\X'tty: link [22m[[4muri[24m [[4mkey[24m[1m=[4m[22mvalue[24m] ...][1m'[0m
              Embed  a  hyperlink  using  the  OSC 8 terminal escape sequence.
              Specifying [4muri[24m starts hyperlinked text, and omitting it ends the
              hyperlink.  When  [4muri[24m  is  present,  any  number  of  additional
              key/value  pairs  can  be specified; their interpretation is the
              responsibility of the pager or terminal.  Spaces or tabs  cannot
              appear literally in [4muri[24m, [4mkey[24m, or [4mvalue[24m; they must be represented
              in an alternate form.

   [1mDevice description files[0m
       If  the [4mDESC[24m file for the character encoding contains the “[1municode[22m” di‐
       rective, [4mgrotty[24m emits Unicode characters in UTF‐8 encoding.  Otherwise,
       it emits characters in a single‐byte encoding depending on the data  in
       the font description files.  See [4mgroff_font[24m(5).

       A  font description file may contain a directive “[1minternalname [4m[22mn[24m” where
       [4mn[24m is a decimal integer.  If the 01 bit in [4mn[24m is set, then  the  font  is
       treated  as an italic font; if the 02 bit is set, then it is treated as
       a bold font.

   [1mTypefaces[0m
       [4mgrotty[24m supports the standard four styles:  [1mR  [22m(roman),  [1mI  [22m([4mitalic[24m),  [1mB[0m
       ([1mbold[22m),  and  [1mBI  [22m([4m[1mbold‐italic[24m[22m).  Because the output driver operates in
       [4mnroff[24m mode, attempts to set or change the font family or type size  are
       ignored.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-b     [22mSuppress the use of overstriking for bold characters  in  legacy
              output format.

       [1m-B     [22mUse  only overstriking for bold‐italic characters in legacy out‐
              put format.

       [1m-c     [22mUse [4mgrotty[24m’s legacy output format (see subsection “Legacy output
              format” above).  SGR and OSC escape sequences are not emitted.

       [1m-d     [22mIgnore all [1m\D [22mdrawing escape sequences in  the  input.   By  de‐
              fault,  [4mgrotty[24m  renders  [1m\D'l[22m...[1m'  [22mescape sequences that have at
              least one zero argument (and so are either horizontal or  verti‐
              cal)  using Unicode box drawing characters (for the [1mutf8 [22mdevice)
              or the [1m-[22m, [1m|[22m, and [1m+ [22mcharacters (for all other  devices).   [4mgrotty[0m
              handles [1m\D'p[22m...[1m' [22mescape sequences that consist entirely of hori‐
              zontal and vertical lines similarly.

       [1m-f     [22mEmit a form feed at the end of each page having no output on its
              last line.

       [1m-F [4m[22mdir[24m Prepend  directory  dir[4m/dev[24mname  to the search path for font and
              device description files; [4mname[24m  describes  the  output  device’s
              character encoding, one of [1mascii[22m, [1mlatin1[22m, [1mutf8[22m, or [1mcp1047[22m.

       [1m-h     [22mUse  literal  horizontal tab characters in the output.  Tabs are
              assumed to be set every 8 columns.

       [1m-i     [22mRender oblique‐styled fonts ([1mI [22mand [1mBI[22m) with  the  SGR  attribute
              for  italic  text  rather  than underlined text.  Many terminals
              don’t  support  this   attribute;   however,   [4mxterm[24m(1),   since
              patch #314 (2014‐12‐28), does.  Ignored if [1m-c [22mis also specified.

       [1m-o     [22mSuppress  overstriking  (other  than  for bold and/or underlined
              characters when the legacy output format is in use).

       [1m-r     [22mRender oblique‐styled fonts ([1mI [22mand [1mBI[22m) with  the  SGR  attribute
              for  reverse video text rather than underlined text.  Ignored if
              [1m-c [22mor [1m-i [22mis also specified.

       [1m-u     [22mSuppress the use of underlining for italic characters in  legacy
              output format.

       [1m-U     [22mUse only underlining for bold‐italic characters in legacy output
              format.

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[0m
              A  list  of directories in which to seek the selected output de‐
              vice’s directory of device  and  font  description  files.   See
              [4mtroff[24m(1) and [4mgroff_font[24m(5).

       [4mGROFF_NO_SGR[0m
              If  set, [4mgrotty[24m’s legacy output format is used just as if the [1m-c[0m
              option were specified; see  subsection  “Legacy  output  format”
              above.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devascii/DESC[0m
              describes the [1mascii [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devascii/[24mF
              describes the font known as [4mF[24m on device [1mascii[22m.

       [4m/usr/share/groff/1.23.0/font/devcp1047/DESC[0m
              describes the [1mcp1047 [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devcp1047/[24mF
              describes the font known as [4mF[24m on device [1mcp1047[22m.

       [4m/usr/share/groff/1.23.0/font/devlatin1/DESC[0m
              describes the [1mlatin1 [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devlatin1/[24mF
              describes the font known as [4mF[24m on device [1mlatin1[22m.

       [4m/usr/share/groff/1.23.0/font/devutf8/DESC[0m
              describes the [1mutf8 [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devutf8/[24mF
              describes the font known as [4mF[24m on device [1mutf8[22m.

       [4m/usr/share/groff/1.23.0/tmac/tty.tmac[0m
              defines  macros for use with the [1mascii[22m, [1mcp1047[22m, [1mlatin1[22m, and [1mutf8[0m
              output devices.  It is automatically loaded by [4mtroffrc[24m when  any
              of those output devices is selected.

       [4m/usr/share/groff/1.23.0/tmac/tty-char.tmac[0m
              defines fallback characters for use with [4mgrotty.[24m  See [4mnroff[24m(1).

[1mLimitations[0m
       [4mgrotty[24m is intended only for simple documents.

       • There is no support for fractional horizontal or vertical motions.

       • [4mroff[24m [1m\D [22mescape sequences producing anything other than horizontal and
         vertical lines are not supported.

       • Characters above the first line (that is, with a vertical drawing po‐
         sition of 0) cannot be rendered.

       • Color handling differs from other output drivers.  The [4mgroff[24m requests
         and  escape sequences that set the stroke and fill colors instead set
         the foreground and background character cell colors, respectively.

[1mExamples[0m
       The following [4mgroff[24m document exercises several features for which  out‐
       put  device  support  varies:  (1)  bold  style; (2) italic (underline)
       style; (3) bold‐italic style; (4) character composition by overstriking
       (“coöperate”); (5) foreground color; (6) background color; and (7) hor‐
       izontal and vertical line‐drawing.

              You might see \f[B]bold\f[] and \f[I]italic\f[].
              Some people see \f[BI]both\f[].
              If the output device does (not) co\z\[ad]operate,
              you might see \m[red]red\m[].
              Black on cyan can have a \M[cyan]\m[black]prominent\m[]\M[]
              \D'l 1i 0'\D'l 0 2i'\D'l 1i 0' look.
              .\" If in nroff mode, end page now.
              .if n .pl \n[nl]u

       Given the foregoing input, compare and contrast the output of the  fol‐
       lowing.

              $ [1mgroff -T ascii [4m[22mfile[0m
              $ [1mgroff -T utf8 -P -i [4m[22mfile[0m
              $ [1mgroff -T utf8 -P -c [4m[22mfile[24m [1m| ul[0m

[1mSee also[0m
       “Control  Functions  for  Coded  Character Sets” (ECMA‐48) 5th edition,
       Ecma International, June 1991.  A gratis version of ISO 6429, this doc‐
       ument includes a normative description of SGR escape sequences.  Avail‐
       able at  ⟨http://www.ecma-international.org/publications/files/ECMA-ST/
       Ecma-048.pdf⟩.

       “Hyperlinks  in Terminal Emulators” ⟨https://gist.github.com/egmontkob/
       eb114294efbcd5adb1944c9f3cb5feda⟩, Egmont Koblinger.

       [4mgroff[24m(1), [4mtroff[24m(1), [4mgroff_out[24m(5), [4mgroff_font[24m(5), [4mgroff_char[24m(7),  [4mul[24m(1),
       [4mmore[24m(1), [4mless[24m(1), [4mman[24m(1)

groff 1.23.0                      5 July 2023                        [4mgrotty[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mhpftodit[24m(1)                 General Commands Manual                [4mhpftodit[24m(1)

[1mName[0m
       hpftodit - create font description files for use with [4mgroff[24m and [4mgrolj4[0m

[1mSynopsis[0m
       [1mhpftodit [22m[[1m-aqs[22m] [[1m-i [4m[22mn[24m] [4mtfm‐file[24m [4mmap‐file[24m [4mfont‐description[0m

       [1mhpftodit -d [4m[22mtfm‐file[24m [[4mmap‐file[24m]

       [1mhpftodit --help[0m

       [1mhpftodit -v[0m
       [1mhpftodit --version[0m

[1mDescription[0m
       [4mhpftodit[24m creates a font description file for use with a Hewlett‐Packard
       LaserJet  4‐series  (or newer) printer with the [4mgrolj4[24m(1) output driver
       of [4mgroff[24m(1), using data from an HP tagged font metric (TFM) file.  [4mtfm‐[0m
       [4mfile[24m is the name of the font’s TFM file; Intellifont and  TrueType  TFM
       files  are  supported, but symbol set TFM files are not.  [4mmap‐file[24m is a
       file giving the [4mgroff[24m special character identifiers for glyphs  in  the
       font; this file should consist of a sequence of lines of the form
              [4mm[24m [4mu[24m [4mc1[24m [4mc2[24m ... [# [4mcomment[24m]
       where  [4mm[24m  is  a  decimal  integer giving the glyph’s MSL (Master Symbol
       List) number, [4mu[24m is a hexadecimal integer giving its  Unicode  character
       code, and [4mc1[24m, [4mc2[24m, ...  are its [4mgroff[24m glyph names (see [4mgroff_char[24m(7) for
       a  list).   The  values can be separated by any number of spaces and/or
       tabs.  The Unicode value must use uppercase hexadecimal digits A–F, and
       must lack a leading “[1m0x[22m”, “[1mu[22m”, or “[1mU+[22m”.  Unicode  values  corresponding
       to   composite   glyphs   are   decomposed;  that  is  “[1mu00C0[22m”  becomes
       “[1mu0041_0300[22m”.  A glyph without a [4mgroff[24m special character identifier may
       be named [1mu[4m[22mXXXX[24m if the glyph corresponds to a Unicode value,  or  as  an
       unnamed  glyph “[1m---[22m”.  If the given Unicode value is in the Private Use
       Area (PUA) (0xE000–0xF8FF), the glyph is included as an unnamed  glyph.
       Refer  to [4mgroff_diff[24m(1) for additional information about unnamed glyphs
       and how to access them.

       Blank lines and lines beginning with “[1m#[22m” are ignored.  A “[1m#[22m”  following
       one or more [4mgroff[24m names begins a comment.  Because “[1m#[22m” is a valid [4mgroff[0m
       name, it must appear first in a list of [4mgroff[24m names if a comment is in‐
       cluded, as in
              3   0023   #   # number sign
       or
              3   0023   # sh   # number sign
       whereas in
              3   0023   sh #   # number sign
       the first “[1m#[22m” is interpreted as the beginning of the comment.

       Output  is  written in [4mgroff_font[24m(5) format to [4mfont‐description,[24m a file
       named for the intended [4mgroff[24m font name; if this  operand  is  “[1m-[22m”,  the
       font description is written to the standard output stream.

       If  the  [1m-i  [22moption  is  used,  [4mhpftodit[24m automatically will generate an
       italic correction, a left italic correction, and a subscript correction
       for each glyph (the significance of these parameters  is  explained  in
       [4mgroff_font[24m(5)).

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-a     [22mInclude glyphs in the TFM file that are  not  included  in  [4mmap‐[0m
              [4mfile[24m.   A  glyph  with  corresponding Unicode value is given the
              name u[4mXXXX[24m; a glyph without a Unicode value is  included  as  an
              unnamed  glyph  “---”.  A glyph with a Unicode value in the Pri‐
              vate Use Area (0xE000–0xF8FF) is also  included  as  an  unnamed
              glyph.

              This  option provides a simple means of adding Unicode‐named and
              unnamed glyphs to a font without including them in the map file,
              but it affords little control over which glyphs are placed in  a
              regular  font and which are placed in a special font.  The pres‐
              ence or absence of the [1m-s [22moption has some effect on which glyphs
              are included: without  it,  only  the  “text”  symbol  sets  are
              searched  for  matching glyphs; with it, only the “mathematical”
              symbol sets are searched.  Nonetheless, restricting  the  symbol
              sets  searched  isn’t  very  selective—many glyphs are placed in
              both regular and special fonts.  Normally,  [1m-a  [22mshould  be  used
              only as a last resort.

       [1m-d     [22mDump  information  about  the  TFM  file  to the standard output
              stream; use this to ensure that a TFM file is a proper match for
              a font, and that its contents are suitable.  The information in‐
              cludes the values of important TFM tags and a  listing  (by  MSL
              number  for  Intellifont TFM files or by Unicode value for True‐
              Type TFM files) of the glyphs included in  the  TFM  file.   The
              unit of measure “DU” for some tags indicates design units; there
              are 8782 design units per em for Intellifont fonts, and 2048 de‐
              sign units per em for TrueType fonts.  Note that the accessibil‐
              ity  of  a  glyph depends on its inclusion in a symbol set; some
              TFM files list many glyphs but only a few symbol sets.

              The glyph listing includes the glyph index within the TFM  file,
              the  MSL or Unicode value, and the symbol set and character code
              that will be used to print the glyph.   If  [4mmap‐file[24m  is  given,
              [4mgroff[24m  names  are  given for matching glyphs.  If only the glyph
              index and MSL or Unicode value are given, the glyph does not ap‐
              pear in any supported symbol set and cannot be printed.

              With the [1m-d [22moption, [4mmap‐file[24m is optional, and [4moutput‐font[24m is ig‐
              nored if given.

       [1m-i [4m[22mn[24m   Generate an italic correction for each glyph so that  its  width
              plus  its  italic  correction is equal to [4mn[24m thousandths of an em
              plus the amount by which the right edge of the glyphs’s bounding
              box is to the right of its origin.  If a negative italic correc‐
              tion would result, use a zero italic correction instead.

              Also generate a subscript correction equal to the product of the
              tangent of the slant of the font and four fifths of the x‐height
              of the font.  If a subscript correction greater than the  italic
              correction would result, use a subscript correction equal to the
              italic correction instead.

              Also generate a left italic correction for each glyph equal to [4mn[0m
              thousandths  of  an em plus the amount by which the left edge of
              the glyphs’s bounding box is to the left  of  its  origin.   The
              left italic correction may be negative.

              This  option  normally  is  needed  only  with italic or oblique
              fonts; a value of 50 (0.05 em) usually is a reasonable choice.

       [1m-q     [22mSuppress warnings about glyphs in the map  file  that  were  not
              found  in  the  TFM  file.  Warnings never are given for unnamed
              glyphs or by glyphs named by their Unicode values.  This  option
              is  useful  when  sending the output of [4mhpftodit[24m to the standard
              output stream.

       [1m-s     [22mAdd the [1mspecial [22mdirective to the font description file,  affect‐
              ing  the  order  in  which  HP symbol sets are searched for each
              glyph.  Without this option, the “text” sets are searched before
              the “mathematical” symbol sets.  With it, the  search  order  is
              reversed.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devlj4/DESC[0m
              describes the [1mlj4 [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devlj4/[24mF
              describes the font known as [4mF[24m on device [1mlj4[22m.

       [4m/usr/share/groff/1.23.0/font/devlj4/generate/Makefile[0m
              is  a  [4mmake[24m(1) script that uses [4mhpftodit[24m(1) to prepare the [4mgroff[0m
              font description files above from HP TFM data; in can be used to
              regenerate them in the event the TFM files are updated.

       [4m/usr/share/groff/1.23.0/font/devlj4/generate/special.awk[0m
              is an [4mawk[24m(1) script that corrects the  Intellifont‐based  height
              metrics  for several glyphs in the [1mS [22m(special) font for TrueType
              CG Times used in the HP LaserJet 4000 and later.

       [4m/usr/share/groff/1.23.0/font/devlj4/generate/special.map[0m
       [4m/usr/share/groff/1.23.0/font/devlj4/generate/symbol.map[0m
       [4m/usr/share/groff/1.23.0/font/devlj4/generate/text.map[0m
       [4m/usr/share/groff/1.23.0/font/devlj4/generate/wingdings.map[0m
              map MSL indices and HP Unicode PUA assignments to [4mgroff[24m  special
              character identifiers.

[1mSee also[0m
       [4mgroff[24m(1), [4mgroff_diff[24m(1), [4mgrolj4[24m(1), [4mgroff_font[24m(5)

groff 1.23.0                      5 July 2023                      [4mhpftodit[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mindxbib[24m(1)                  General Commands Manual                 [4mindxbib[24m(1)

[1mName[0m
       indxbib - make inverted index for bibliographic databases

[1mSynopsis[0m
       [1mindxbib [22m[[1m-w[22m] [[1m-c [4m[22mcommon‐words‐file[24m] [[1m-d [4m[22mdir[24m] [[1m-f [4m[22mlist‐file[24m]
               [[1m-h [4m[22mmin‐hash‐table‐size[24m] [[1m-i [4m[22mexcluded‐fields[24m]
               [[1m-k [4m[22mmax‐keys‐per‐record[24m] [[1m-l [4m[22mmin‐key‐length[24m] [[1m-n [4m[22mthreshold[24m]
               [[1m-o [4m[22mfile[24m] [[1m-t [4m[22mmax‐key‐length[24m] [[4mfile[24m ...]

       [1mindxbib --help[0m

       [1mindxbib -v[0m
       [1mindxbib --version[0m

[1mDescription[0m
       [4mindxbib[24m makes an inverted index for the bibliographic databases in each
       [4mfile[24m for use with [4mrefer[24m(1), [4mlookbib[24m(1), and [4mlkbib[24m(1).  Each created in‐
       dex  is named file[4m.i[24m; writing is done to a temporary file which is then
       renamed to this.  If no [4mfile[24m operands are given on the command line be‐
       cause the [1m-f [22moption has been used, and no [1m-o [22moption is given, the index
       will be named [4mInd.i[24m.

       Bibliographic databases  are  divided  into  records  by  blank  lines.
       Within  a record, each field starts with a [1m% [22mcharacter at the beginning
       of a line.  Fields have a one letter name that follows the [1m% [22mcharacter.

       The values set by the [1m-c[22m, [1m-l[22m, [1m-n[22m, and [1m-t [22moptions are stored in the  in‐
       dex:  when  the index is searched, keys will be discarded and truncated
       in a manner appropriate to these options; the  original  keys  will  be
       used  for verifying that any record found using the index actually con‐
       tains the keys.  This means that a user  of  an  index  need  not  know
       whether  these options were used in the creation of the index, provided
       that not all the keys to be searched for would have been discarded dur‐
       ing indexing and that the user supplies at least the part of  each  key
       that  would  have  remained after being truncated during indexing.  The
       value set by the [1m-i [22moption is also stored in the index and will be used
       in verifying records found using the index.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-c [4m[22mcommon‐words‐file[0m
              Read  the list of common words from [4mcommon‐words‐file[24m instead of
              [4m/usr/share/groff/1.23.0/eign[24m.

       [1m-d [4m[22mdir[24m Use [4mdir[24m as the name of the directory to store in the index,  in‐
              stead  of  that returned by [4mgetcwd[24m(2).  Typically, [4mdir[24m will be a
              symbolic link whose target is the current working directory.

       [1m-f [4m[22mlist‐file[0m
              Read the files to be indexed from [4mlist‐file[24m.  If [4mlist‐file[24m is [1m-[22m,
              files will be read from the standard input stream.  The  [1m-f  [22mop‐
              tion can be given at most once.

       [1m-h [4m[22mmin‐hash‐table‐size[0m
              Use the first prime number greater than or equal to the argument
              for the size of the hash table.  Larger values will usually make
              searching  faster, but will make the index file larger and cause
              [4mindxbib[24m to use more memory.  The default hash table size is 997.

       [1m-i [4m[22mexcluded‐fields[0m
              Don’t index the contents of fields whose names are in  [4mexcluded‐[0m
              [4mfields[24m.   Field names are one character each.  If this option is
              not present, [4mindxbib[24m excludes fields [1mX[22m, [1mY[22m, and [1mZ[22m.

       [1m-k [4m[22mmax‐keys‐per‐record[0m
              Use no more keys per input record than specified  in  the  argu‐
              ment.  If this option is not present, the maximum is 100.

       [1m-l [4m[22mmin‐key‐length[0m
              Discard  any  key whose length in characters is shorter than the
              value of the argument.  If this option is not present, the mini‐
              mum key length is 3.

       [1m-n [4m[22mthreshold[0m
              Discard the [4mthreshold[24m most common words from  the  common  words
              file.   If this option is not present, the 100 most common words
              are discarded.

       [1m-o [4m[22mbasename[0m
              Name the index basename[4m.i[24m.

       [1m-t [4m[22mmax‐key‐length[0m
              Truncate keys to [4mmax‐key‐length[24m in characters.  If  this  option
              is not present, keys are truncated to 6 characters.

       [1m-w     [22mIndex whole files.  Each file is a separate record.

[1mFiles[0m
       file[4m.i[24m index for [4mfile[0m

       [4mInd.i[24m  default index name

       [4m/usr/share/groff/1.23.0/eign[0m
              contains  the  list  of  common  words.   The  traditional name,
              “[4meign[24m”, is an abbreviation of “English ignored [word list]”.

       [4mindxbib[24mXXXXXX
              temporary file

[1mSee also[0m
       “Some Applications of Inverted Indexes on the Unix System”,  by  M.  E.
       Lesk,  1978,  AT&T Bell Laboratories Computing Science Technical Report
       No. 69.

       [4mrefer[24m(1), [4mlkbib[24m(1), [4mlookbib[24m(1)

groff 1.23.0                      5 July 2023                       [4mindxbib[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mlkbib[24m(1)                    General Commands Manual                   [4mlkbib[24m(1)

[1mName[0m
       lkbib - search bibliographic databases

[1mSynopsis[0m
       [1mlkbib [22m[[1m-n[22m] [[1m-i [4m[22mfields[24m] [[1m-p [4m[22mfile[24m] ... [[1m-t [4m[22mn[24m] [4mkey[24m ...

       [1mlkbib --help[0m

       [1mlkbib -v[0m
       [1mlkbib --version[0m

[1mDescription[0m
       [4mlkbib[24m searches bibliographic databases for references  containing  key‐
       words  [4mkey[24m  and  writes  any  references  found  to the standard output
       stream.  It reads databases given by [1m-p [22moptions and then (unless [1m-n  [22mis
       given)  a  default  database.   The  default database is taken from the
       [4mREFER[24m environment variable if it is set,  otherwise  it  is  [4m/usr/dict/[0m
       [4mpapers/Ind[24m.   For each database [4mfile[24m to be searched, if an index file[4m.i[0m
       created by [4mindxbib[24m(1) exists, then it will be  searched  instead;  each
       index can cover multiple databases.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-i [4m[22mstring[0m
              When searching files for which no index exists, ignore the  con‐
              tents of fields whose names are in [4mstring[24m.

       [1m-n     [22mSuppress search of default database.

       [1m-p [4m[22mfile[0m
              Search [4mfile[24m.  Multiple [1m-p [22moptions can be used.

       [1m-t [4m[22mn[24m   Require  only  the  first [4mn[24m characters of keys to be given.  The
              default is 6.

[1mEnvironment[0m
       [4mREFER[24m  Default database.

[1mFiles[0m
       [4m/usr/dict/papers/Ind[0m
              Default database to be used if the [4mREFER[24m environment variable is
              not set.

       file[4m.i[24m Index files.

[1mSee also[0m
       “Some Applications of Inverted Indexes on the Unix System”,  by  M.  E.
       Lesk,  1978,  AT&T Bell Laboratories Computing Science Technical Report
       No. 69.

       [4mrefer[24m(1), [4mlookbib[24m(1), [4mindxbib[24m(1)

groff 1.23.0                      5 July 2023                         [4mlkbib[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mlookbib[24m(1)                  General Commands Manual                 [4mlookbib[24m(1)

[1mName[0m
       lookbib - search bibliographic databases

[1mSynopsis[0m
       [1mlookbib [22m[[1m-i [4m[22mstring[24m] [[1m-t [4m[22mn[24m] [4mfile[24m ...

       [1mlookbib --help[0m

       [1mlookbib -v[0m
       [1mlookbib --version[0m

[1mDescription[0m
       [4mlookbib[24m writes a prompt to the standard error stream (unless the  stan‐
       dard  input  stream is not a terminal), reads from the standard input a
       line containing a set of keywords, searches each bibliographic database
       [4mfile[24m for references containing those keywords,  writes  any  references
       found to the standard output stream, and repeats this process until the
       end  of  input.   For  each  database  [4mfile[24m to be searched, if an index
       file[4m.i[24m created by [4mindxbib[24m(1) exists, then it will be searched  instead;
       each index can cover multiple databases.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-i [4m[22mstring[0m
              When searching files for which no index exists, ignore the  con‐
              tents of fields whose names are in [4mstring[24m.

       [1m-t [4m[22mn[24m   Require  only  the  first [4mn[24m characters of keys to be given.  The
              default is 6.

[1mFiles[0m
       file[4m.i[24m Index files.

[1mSee also[0m
       “Some Applications of Inverted Indexes on the Unix System”,  by  M.  E.
       Lesk,  1978,  AT&T Bell Laboratories Computing Science Technical Report
       No. 69.

       [4mrefer[24m(1), [4mlkbib[24m(1), [4mindxbib[24m(1)

groff 1.23.0                      5 July 2023                       [4mlookbib[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mmmroff[24m(1)                   General Commands Manual                  [4mmmroff[24m(1)

[1mName[0m
       mmroff - cross‐referencing front end for GNU [4mroff[24m [4mmm[24m macro package

[1mSynopsis[0m
       [1mmmroff [22m[[1m-x[22m] [4mgroff‐argument[24m ...

       [1mmmroff --help[0m

       [1mmmroff --version[0m

[1mDescription[0m
       [4mmmroff[24m is a simple wrapper for [4mgroff[24m, used to expand  cross  references
       in [4mmm[24m; see [4mgroff_mm[24m(7).  It runs [4mgroff[24m with the [1m-mm [22moption twice, first
       with  [1m-z  [22mand  [1m-rRef=1 [22mto populate cross‐reference and index files with
       their corresponding entries, and then again to  produce  the  document.
       It  also handles the inclusion of PostScript images with the [1mPIC [22mmacro.
       Documents that do not use these features of [4mgroff[24m [4mmm[24m (the  [1mINITI[22m,  [1mIND[22m,
       [1mINDP[22m,  [1mINITR[22m,  [1mSETR[22m,  [1mGETHN[22m, [1mGETPN[22m, [1mGETR[22m, [1mGETST[22m, and [1mPIC [22mmacros) do not
       require [4mmmroff[24m.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m--version [22mshows version informa‐
       tion; both exit afterward.

       [1m-x     [22mCreate or update the cross‐reference file and exit.

[1mAuthors[0m
       [4mmmroff[24m was written by Jörgen Hägg ⟨jh@axis.se⟩ of Lund, Sweden.

[1mSee also[0m
       [4mgroff_mm[24m(7), [4mgroff_mmse[24m(7), [4mgroff[24m(1), [4mtroff[24m(1), [4mtbl[24m(1), [4mpic[24m(1), [4meqn[24m(1)

groff 1.23.0                      5 July 2023                        [4mmmroff[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mneqn[24m(1)                     General Commands Manual                    [4mneqn[24m(1)

[1mName[0m
       neqn - format equations for character‐cell terminal output

[1mSynopsis[0m
       [1mneqn [22m[[4meqn‐argument[24m ...]

[1mDescription[0m
       [4mneqn[24m invokes the [4meqn[24m(1) command with the [1mascii [22moutput device.

       [4meqn[24m does not support low‐resolution, typewriter‐like devices,  although
       it may work adequately for very simple input.

[1mSee also[0m
       [4meqn[24m(1)

groff 1.23.0                      5 July 2023                          [4mneqn[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mnroff[24m(1)                    General Commands Manual                   [4mnroff[24m(1)

[1mName[0m
       nroff - format documents with [4mgroff[24m for TTY (terminal) devices

[1mSynopsis[0m
       [1mnroff [22m[[1m-bcCEhikpRStUVz[22m] [[1m-d [4m[22mctext[24m] [[1m-d [4m[22mstring[24m[1m=[4m[22mtext[24m] [[1m-K [4m[22mfallback‐[0m
             [4mencoding[24m] [[1m-m [4m[22mmacro‐package[24m] [[1m-M [4m[22mmacro‐directory[24m] [[1m-n [4m[22mpage‐[0m
             [4mnumber[24m] [[1m-o [4m[22mpage‐list[24m] [[1m-P [4m[22mpostprocessor‐argument[24m] [[1m-r [4m[22mcnumeric‐[0m
             [4mexpression[24m] [[1m-r [4m[22mregister[24m[1m=[4m[22mnumeric‐expression[24m] [[1m-T [4m[22moutput‐device[24m]
             [[1m-w [4m[22mwarning‐category[24m] [[1m-W [4m[22mwarning‐category[24m] [[4mfile[24m ...]

       [1mnroff --help[0m

       [1mnroff -v[0m
       [1mnroff --version[0m

[1mDescription[0m
       [4mnroff[24m  formats  documents  written  in  the [4mgroff[24m(7) language for type‐
       writer‐like devices such as terminal emulators.  GNU [4mnroff[24m emulates the
       AT&T  [4mnroff[24m  command  using  [4mgroff[24m(1).   [4mnroff[24m  generates  output   via
       [4mgrotty[24m(1),  [4mgroff[24m’s  terminal  output  driver,  which needs to know the
       character encoding scheme used by the device.  Consequently, acceptable
       arguments to the [1m-T [22moption are [1mascii[22m, [1mlatin1[22m,  [1mutf8[22m,  and  [1mcp1047[22m;  any
       others  are ignored.  If neither the [4mGROFF_TYPESETTER[24m environment vari‐
       able nor the [1m-T [22mcommand‐line option (which  overrides  the  environment
       variable)  specifies a (valid) device, [4mnroff[24m consults the locale to se‐
       lect an appropriate output device.  It first tries the  [4mlocale[24m(1)  pro‐
       gram,  then  checks  several  locale‐related environment variables; see
       section “Environment” below.  If all of the foregoing fail, [1m-Tascii  [22mis
       implied.

       The  [1m-b[22m, [1m-c[22m, [1m-C[22m, [1m-d[22m, [1m-E[22m, [1m-i[22m, [1m-m[22m, [1m-M[22m, [1m-n[22m, [1m-o[22m, [1m-r[22m, [1m-U[22m, [1m-w[22m, [1m-W[22m, and [1m-z [22mop‐
       tions have the effects described in [4mtroff[24m(1).  [1m-c [22mand [1m-h  [22mimply  “[1m-P-c[22m”
       and “[1m-P-h[22m”, respectively; [1m-c [22mis also interpreted directly by [4mtroff[24m.  In
       addition,  this  implementation  ignores the AT&T [4mnroff[24m options [1m-e[22m, [1m-q[22m,
       and [1m-s [22m(which are not implemented in [4mgroff[24m).  The options [1m-k[22m,  [1m-K[22m,  [1m-p[22m,
       [1m-P[22m, [1m-R[22m, [1m-t[22m, and [1m-S [22mare documented in [4mgroff[24m(1).  [1m-V [22mcauses [4mnroff[24m to dis‐
       play  the  constructed [4mgroff[24m command on the standard output stream, but
       does not execute it.  [1m-v [22mand [1m--version [22mshow version  information  about
       [4mnroff[24m  and the programs it runs, while [1m--help [22mdisplays a usage message;
       all exit afterward.

[1mExit status[0m
       [4mnroff[24m exits with error status [1m2 [22mif there was a problem parsing its  ar‐
       guments,  with  status  [1m0  [22mif  any of the options [1m-V[22m, [1m-v[22m, [1m--version[22m, or
       [1m--help [22mwere specified, and with the status of [4mgroff[24m otherwise.

[1mEnvironment[0m
       Normally, the path separator in environment variables ending with  [4mPATH[0m
       is the colon; this may vary depending on the operating system.  For ex‐
       ample, Windows uses a semicolon instead.

       [4mGROFF_BIN_PATH[0m
              is  a colon‐separated list of directories in which to search for
              the [4mgroff[24m executable before searching in [4mPATH[24m.  If unset,  [4m/usr/[0m
              [4mbin[24m is used.

       [4mGROFF_TYPESETTER[0m
              specifies the default output device for [4mgroff[24m.

       [4mLC_ALL[0m
       [4mLC_CTYPE[0m
       [4mLANG[0m
       [4mLESSCHARSET[0m
              are pattern‐matched in this order for contents matching standard
              character encodings supported by [4mgroff[24m in the event no [1m-T [22moption
              is  given and [4mGROFF_TYPESETTER[24m is unset, or the values specified
              are invalid.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/tty-char.tmac[0m
              defines fallback definitions of [4mroff[24m special characters.   These
              definitions  more  poorly  optically  approximate typeset output
              than those of [4mtty.tmac[24m in favor of communicating semantic infor‐
              mation.  [4mnroff[24m loads it automatically.

[1mNotes[0m
       Pager programs like [4mmore[24m(1) and [4mless[24m(1) may  require  command‐line  op‐
       tions to correctly handle some output sequences; see [4mgrotty[24m(1).

[1mSee also[0m
       [4mgroff[24m(1), [4mtroff[24m(1), [4mgrotty[24m(1), [4mlocale[24m(1), [4mroff[24m(7)

groff 1.23.0                      5 July 2023                         [4mnroff[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mpdfmom[24m(1)                   General Commands Manual                  [4mpdfmom[24m(1)

[1mName[0m
       pdfmom - produce PDF documents using the [4mmom[24m macro package for [4mgroff[0m

[1mSynopsis[0m
       [1mpdfmom [22m[[1m-Tpdf[22m] [[4mgroff‐options[24m] [[4mfile[24m ...]

       [1mpdfmom -Tps [22m[[4mpdfroff‐options[24m] [[4mgroff‐options[24m] [[4mfile[24m ...]

       [1mpdfmom -v[0m
       [1mpdfmom --version[0m

[1mDescription[0m
       [4mpdfmom[24m  is a wrapper around [4mgroff[24m(1) that facilitates the production of
       PDF documents from files formatted with the [4mmom[24m macros.

       [4mpdfmom[24m prints to the standard output, so output must usually  be  redi‐
       rected to a destination file.  The size of the final PDF can be reduced
       by piping the output through [4mps2pdf[24m(1).

       If  called  with  the  [1m-Tpdf  [22moption  (which  is  the  default), [4mpdfmom[0m
       processes files using [4mgroff[24m’s native PDF driver, [4mgropdf[24m(1).  If [1m-Tps [22mis
       given, processing is passed over to [4mpdfroff[24m, which uses  [4mgroff[24m’s  Post‐
       Script  driver.   In  either case, multiple runs of the source file are
       performed in order to satisfy any forward references in the document.

       [4mpdfmom[24m accepts all the same options as [4mgroff[24m.  If [1m-Tps  [22mis  given,  the
       options  associated  with  [4mpdfroff[24m  are  accepted as well.  When [4mpdfmom[0m
       calls [4mpdfroff[24m, the options “[1m-mpdfmark -mom --no-toc[22m”  options  are  im‐
       plied  and should not be given on the command line.  Equally, it is not
       necessary to supply the [1m-mom [22mor [1m-m mom [22moptions when [1m-Tps [22mis absent.

       PDF integration with the [4mmom[24m macros is discussed in full in the  manual
       “Producing  PDFs  with  [4mgroff[24m  and [4mmom[24m”, which was itself produced with
       [4mpdfmom[24m.

       If called with the [1m-v [22mor [1m--version [22moptions, [4mpdfmom[24m displays its version
       information and exits.

[1mAuthors[0m
       [4mpdfmom[24m was written by Deri James ⟨deri@chuzzlewit.myzen.co.uk⟩ and  Pe‐
       ter Schaffter ⟨peter@schaffter.ca⟩, and is maintained by James.

[1mSee also[0m
       [4m/usr/share/doc/groff-1.23.0/pdf/mom-pdf.pdf[0m
              “Producing  PDFs  with  [4mgroff[24m  and [4mmom[24m”, by Deri James and Peter
              Schaffter.  This file, together with its source, [4mmom-pdf.mom[24m, is
              part of the [4mgroff[24m distribution.

       [4mgroff[24m(1), [4mgropdf[24m(1), [4mpdfroff[24m(1), [4mps2pdf[24m(1)

groff 1.23.0                      5 July 2023                        [4mpdfmom[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mpdfroff[24m(1)                  General Commands Manual                 [4mpdfroff[24m(1)

[1mName[0m
       pdfroff - construct files in Portable Document Format using [4mgroff[0m

[1mSynopsis[0m
       [1mpdfroff [22m[[4mgroff‐option[24m] [[1m--emit-ps[22m] [[1m--no-toc-relocation[22m]
               [[1m--no-kill-null-pages[22m] [[1m--stylesheet=[4m[22mname[24m] [[1m--no-pdf-output[22m]
               [[1m--pdf-output=[4m[22mname[24m] [[1m--no-reference-dictionary[22m]
               [[1m--reference-dictionary=[4m[22mname[24m] [[1m--report-progress[22m]
               [[1m--keep-temporary-files[22m] [[4mfile[24m ...]

       [1mpdfroff -h[0m
       [1mpdfroff --help[0m

       [1mpdfroff -v [22m[[4mgroff‐option[24m ...]
       [1mpdfroff --version [22m[[4mgroff‐option[24m ...]

       [4mgroff‐option[24m is any short option supported by [4mgroff[24m(1) except  for  [1m-h[22m,
       [1m-T[22m, and [1m-v[22m; see section “Usage” below.

[1mDescription[0m
       [4mpdfroff[24m is a wrapper program for the GNU text processing system, [4mgroff[24m.
       It  transparently handles the mechanics of multiple pass [4mgroff[24m process‐
       ing, when applied to suitably marked up [4mgroff[24m source files,  such  that
       tables of contents and body text are formatted separately, and are sub‐
       sequently  combined  in  the  correct order, for final publication as a
       single PDF document.  A further optional “style  sheet”  capability  is
       provided;  this  allows for the definition of content which is required
       to precede the table of contents, in the published document.

       For each invocation of [4mpdfroff[24m, the ultimate  [4mgroff[24m  output  stream  is
       post‐processed  by  the Ghostscript [4mgs[24m(1) interpreter to produce a fin‐
       ished PDF document.

       [4mpdfroff[24m makes no assumptions about, and imposes no restrictions on, the
       use of any [4mgroff[24m macro packages which the user may choose to employ, in
       order to achieve a desired document format; however,  it  [4mdoes[24m  include
       specific  built  in  support  for the [4mpdfmark[24m macro package, should the
       user choose to employ it.  Specifically, if the [4mpdfhref[24m macro,  defined
       in  the [4mpdfmark.tmac[24m package, is used to define public reference marks,
       or dynamic links to such reference marks, then [4mpdfroff[24m performs as many
       preformatting [4mgroff[24m passes as required, up to a maximum limit of  [4mfour[24m,
       in  order to compile a document reference dictionary, to resolve refer‐
       ences, and to expand the dynamically defined content of links.

[1mUsage[0m
       The command line is parsed in accordance with normal  GNU  conventions,
       but  with  one exception—when specifying any short form option (i.e., a
       single character option introduced by a single hyphen), and if that op‐
       tion expects an argument,  then  it  [4mmust[24m  be  specified  independently
       (i.e.,  it  may  [4mnot[24m be appended to any group of other single character
       short form options).

       Long form option names (i.e., those introduced by a double hyphen)  may
       be abbreviated to their minimum length unambiguous initial substring.

       Otherwise, [4mpdfroff[24m usage closely mirrors that of [4mgroff[24m itself.  Indeed,
       with  the  exception  of the [1m-h[22m, [1m-v[22m, and [1m-T [4m[22mdev[24m short form options, and
       all long form options, which are parsed internally by [4mpdfroff[24m, all  op‐
       tions  and file name arguments specified on the command line are passed
       on to [4mgroff[24m, to control the formatting of  the  PDF  document.   Conse‐
       quently,  [4mpdfroff[24m  accepts  all  options and arguments, as specified in
       [4mgroff[24m(1), which may also be considered as the definitive reference  for
       all standard [4mpdfroff[24m options and argument usage.

[1mOptions[0m
       [4mpdfroff[24m  accepts  all of the short form options (i.e., those introduced
       by a single hyphen), which are available with [4mgroff[24m  itself.   In  most
       cases,  these  are simply passed transparently to [4mgroff[24m; the following,
       however, are handled specially by [4mpdfroff[24m.

       [1m-h     [22mSame as [1m--help[22m; see below.

       [1m-i     [22mProcess standard input, after all other specified  input  files.
              This  is  passed  transparently  to  [4mgroff[24m, but, if grouped with
              other options, it [4mmust[24m be the first in  the  group.   Hiding  it
              within  a  group breaks standard input processing, in the multi‐
              ple‐pass [4mgroff[24m processing context of [4mpdfroff[24m.

       [1m-T [4m[22mdev[24m Only [1m-T ps [22mis supported by [4mpdfroff[24m.  Attempting to  specify  any
              other device causes [4mpdfroff[24m to abort.

       [1m-v     [22mSame as [1m--version[22m; see below.

       See  [4mgroff[24m(1)  for a description of all other short form options, which
       are transparently passed through [4mpdfroff[24m to [4mgroff[24m.

       All long form options (i.e., those introduced by a double  hyphen)  are
       interpreted locally by [4mpdfroff[24m; they are [4mnot[24m passed on to [4mgroff[24m, unless
       otherwise stated below.

       [1m--help [22mCauses [4mpdfroff[24m to display a summary of the its usage syntax, and
              supported options, and then exit.

       [1m--emit-ps[0m
              Suppresses  the final output conversion step, causing [4mpdfroff[24m to
              emit PostScript output instead of PDF.  This may  be  useful  to
              capture  intermediate PostScript output when using a specialised
              postprocessor, such as [4mgpresent[24m for example, in place of the de‐
              fault Ghostscript PDF writer.

       [1m--keep-temporary-files[0m
              Suppresses the deletion of temporary files, which  normally  oc‐
              curs  after  [4mpdfroff[24m has completed PDF document formatting; this
              may be useful when debugging formatting problems.

              See section “Files” below for a  description  of  the  temporary
              files used by [4mpdfroff[24m.

       [1m--no-pdf-output[0m
              May  be  used  with  the [1m--reference-dictionary=[4m[22mname[24m option (de‐
              scribed below) to eliminate the overhead of PDF formatting  when
              running  [4mpdfroff[24m  to  create a reference dictionary for use in a
              different document.

       [1m--no-reference-dictionary[0m
              May be used to eliminate the overhead of  creating  a  reference
              dictionary,  when  it is known that the target PDF document con‐
              tains no public references, created by the [1mpdfhref [22mmacro.

       [1m--no-toc-relocation[0m
              May be used to eliminate the extra [4mgroff[24m processing pass,  which
              is  required to generate a table of contents, and relocate it to
              the start of the PDF  document,  when  processing  any  document
              which lacks an automatically generated table of contents.

       [1m--no-kill-null-pages[0m
              While  preparing  for  simulation  of the manual collation step,
              which is traditionally required to relocate a [4mtable[24m [4mof[24m  [4mcontents[0m
              to  the  start  of  a  document, [4mpdfroff[24m accumulates a number of
              empty page descriptions into the intermediate PostScript  output
              stream.   During the final collation step, these empty pages are
              normally discarded  from  the  finished  document;  this  option
              forces [4mpdfroff[24m to leave them in place.

       [1m--pdf-output=[4m[22mname[0m
              Specifies the name to be used for the resultant PDF document; if
              unspecified,  the  PDF  output is written to standard output.  A
              future version of [4mpdfroff[24m may use this  option,  to  encode  the
              document name in a generated reference dictionary.

       [1m--reference-dictionary=[4m[22mname[0m
              Specifies  the  name to be used for the generated reference dic‐
              tionary file; if unspecified, the reference dictionary  is  cre‐
              ated  in  a  temporary  file, which is deleted when [4mpdfroff[24m com‐
              pletes processing of the current document.  This option [4mmust[24m  be
              specified,  if  it  is desired to save the reference dictionary,
              for use in references placed in other PDF documents.

       [1m--report-progress[0m
              Causes [4mpdfroff[24m to display an informational message  on  standard
              error, at the start of each [4mgroff[24m processing pass.

       [1m--stylesheet=[4m[22mname[0m
              Specifies the name of an [4minput[24m [4mfile[24m, to be used as a style sheet
              for  formatting of content, which is to be placed [4mbefore[24m the ta‐
              ble of contents, in the formatted PDF document.

       [1m--version[0m
              Causes [4mpdfroff[24m to display a version identification message.  The
              entire command line is then passed transparently to [4mgroff[24m, in  a
              [4mone[24m  pass  operation  [4monly[24m,  in  order to display the associated
              [4mgroff[24m version information, before exiting.

[1mEnvironment[0m
       The following environment variables may be set, and exported, to modify
       the behaviour of [4mpdfroff[24m.

       [4mPDFROFF_COLLATE[0m
              Specifies the program to be used for collation of  the  finished
              PDF document.

              This  collation  step may be required to move [4mtables[24m [4mof[24m [4mcontents[0m
              to the start of the finished PDF document, when formatting  with
              traditional  macro  packages, which print them at the end.  How‐
              ever, users should not normally need to specify [4mPDFROFF_COLLATE[24m,
              (and indeed, are not encouraged  to  do  so).   If  unspecified,
              [4mpdfroff[24m uses [4msed[24m(1) by default, which normally suffices.

              If  [4mPDFROFF_COLLATE[24m  [4mis[24m specified, then it must act as a filter,
              accepting a list of file name arguments, and write its output to
              the  standard  output  stream,  whence  it  is  piped   to   the
              [4mPDFROFF_POSTPROCESSOR_COMMAND[24m,  to produce the finished PDF out‐
              put.

              When specifying [4mPDFROFF_COLLATE[24m, it  is  normally  necessary  to
              also specify [4mPDFROFF_KILL_NULL_PAGES[24m.

              [4mPDFROFF_COLLATE[24m  is  ignored,  if  [4mpdfroff[24m  is  invoked with the
              [1m--no-kill-null-pages [22moption.

       [4mPDFROFF_KILL_NULL_PAGES[0m
              Specifies options to be passed to the [4mPDFROFF_COLLATE[24m program.

              It   should   not   normally    be    necessary    to    specify
              [4mPDFROFF_KILL_NULL_PAGES[24m.   The  internal  default  is  a  [4msed[24m(1)
              script, which is intended to remove completely blank pages  from
              the  collated  output stream, and which should be appropriate in
              most applications of [4mpdfroff[24m.  However, if  any  alternative  to
              [4msed[24m(1)  is specified for [4mPDFROFF_COLLATE[24m, then it is likely that
              a     corresponding      alternative      specification      for
              [4mPDFROFF_KILL_NULL_PAGES[24m is required.

              As  in  the  case of [4mPDFROFF_COLLATE[24m, [4mPDFROFF_KILL_NULL_PAGES[24m is
              ignored, if [4mpdfroff[24m is invoked with the [1m--no-kill-null-pages [22mop‐
              tion.

       [4mPDFROFF_POSTPROCESSOR_COMMAND[0m
              Specifies the command to be used for the final document  conver‐
              sion from PostScript intermediate output to PDF.  It must behave
              as  a  filter, writing its output to the standard output stream,
              and must accept an arbitrary number of [4mfiles[24m [4m...[24m arguments, with
              the special case of “[1m-[22m” representing the standard input stream.

              If unspecified, [4mPDFROFF_POSTPROCESSOR_COMMAND[24m defaults to
                   gs -dBATCH -dQUIET -dNOPAUSE -dSAFER -sDEVICE=pdfwrite \
                        -sOutputFile=-

       [4mGROFF_TMPDIR[0m
              Identifies the directory in which [4mpdfroff[24m should  create  tempo‐
              rary  files.   If  [4mGROFF_TMPDIR[24m is [4mnot[24m specified, then the vari‐
              ables [4mTMPDIR[24m, [4mTMP[24m and [4mTEMP[24m are considered in  turn  as  possible
              temporary  file  repositories.   If  none of these are set, then
              temporary files are created in the current directory.

       [4mGROFF_GHOSTSCRIPT_INTERPRETER[0m
              Specifies the program to be invoked when [4mpdfroff[24m converts  [4mgroff[0m
              PostScript  output  to PDF.  If [4mPDFROFF_POSTPROCESSOR_COMMAND[24m is
              specified, then the command name it specifies is [4mimplicitly[24m  as‐
              signed to [4mGROFF_GHOSTSCRIPT_INTERPRETER[24m, overriding any explicit
              setting      specified      in      the     environment.      If
              [4mGROFF_GHOSTSCRIPT_INTERPRETER[24m is  not  specified,  then  [4mpdfroff[0m
              searches the process [4mPATH[24m, looking for a program with any of the
              well  known  names for the Ghostscript interpreter; if no Ghost‐
              script interpreter can be found, [4mpdfroff[24m aborts.

       [4mGROFF_AWK_INTERPRETER[0m
              Specifies the program to be invoked when [4mpdfroff[24m  is  extracting
              reference  dictionary  entries from a [4mgroff[24m intermediate message
              stream.  If [4mGROFF_AWK_INTERPRETER[24m is not specified, then [4mpdfroff[0m
              searches the process [4mPATH[24m, looking for any of the preferred pro‐
              grams, [4mgawk[24m, [4mmawk[24m, [4mnawk[24m, and [4mawk[24m, in  that  order;  if  none  of
              these  are found, [4mpdfroff[24m issues a warning message, and continue
              processing; however, in this case, no  reference  dictionary  is
              created.

       [4mOSTYPE[24m Typically  defined automatically by the operating system, [4mOSTYPE[0m
              is used on Microsoft Win32/MS‐DOS platforms [4monly[24m, to  infer  the
              default [4mPATH_SEPARATOR[24m character, which is used when parsing the
              process [4mPATH[24m to search for external helper programs.

       [4mPATH_SEPARATOR[0m
              If  set,  [4mPATH_SEPARATOR[24m overrides the default separator charac‐
              ter, (‘:’ on POSIX/Unix systems, inferred  from  [4mOSTYPE[24m  on  Mi‐
              crosoft  Win32/MS‐DOS),  which  is used when parsing the process
              [4mPATH[24m to search for external helper programs.

       [4mSHOW_PROGRESS[0m
              If this is set to a non‐empty value, then [4mpdfroff[24m always behaves
              as if the [1m--report-progress [22moption is specified on  the  command
              line.

[1mFiles[0m
       Input  and  output files for [4mpdfroff[24m may be named according to any con‐
       vention of the user’s choice.  Typically, input files may be named  ac‐
       cording  to the choice of the principal normatting macro package, e.g.,
       file[4m.ms[24m might be an input file  for  formatting  using  the  [4mms[24m  macros
       ([4ms.tmac[24m); normally, the final output file should be named file[4m.pdf[24m.

       Temporary  files created by [4mpdfroff[24m are placed in the file system hier‐
       archy, in or below the directory  specified  by  environment  variables
       (see  section  “Environment”  above).  If [4mmktemp[24m(1) is available, it is
       invoked to create a private subdirectory  of  the  nominated  temporary
       files  directory,  (with  subdirectory  name  derived from the template
       [4mpdfroff-XXXXXXXXXX[24m); if this subdirectory is successfully created,  the
       temporary files will be placed within it, otherwise they will be placed
       directly in the directory nominated in the environment.

       All  temporary  files  themselves are named according to the convention
       [4mpdf[24m$$[4m.[24m*, where [4m$$[24m is  the  standard  shell  variable  representing  the
       process  identifier of the [4mpdfroff[24m process itself, and [4m*[24m represents any
       of the extensions used by [4mpdfroff[24m to identify the  following  temporary
       and intermediate files.

       [4mpdf[24m$$[4m.tmp[0m
              A  scratch  pad  file, used to capture reference data emitted by
              [4mgroff[24m, during the [4mreference[24m [4mdictionary[24m compilation phase.

       [4mpdf[24m$$[4m.ref[0m
              The [4mreference[24m [4mdictionary[24m, as compiled in the last but  one  pass
              of  the [4mreference[24m [4mdictionary[24m compilation phase; (at the start of
              the first pass,  this  file  is  created  empty;  in  successive
              passes,  it  contains  the [4mreference[24m [4mdictionary[24m entries, as col‐
              lected in the preceding pass).

              If the [1m--reference-dictionary[22m=[4mname[24m option is specified, this in‐
              termediate file becomes permanent, and  is  named  [4mname[24m,  rather
              than [4mpdf[24m$$[4m.ref[24m.

       [4mpdf[24m$$[4m.cmp[0m
              Used  to  collect [4mreference[24m [4mdictionary[24m entries during the active
              pass of the [4mreference[24m [4mdictionary[24m compilation phase.  At the  end
              of any pass, when the content of [4mpdf[24m$$[4m.cmp[24m compares as identical
              to   [4mpdf[24m$$[4m.ref[24m,   (or   the  corresponding  file  named  by  the
              [1m--reference-dictionary[22m=[4mname[24m option), then  [4mreference[24m  [4mdictionary[0m
              compilation is terminated, and the [4mdocument[24m [4mreference[24m [4mmap[24m is ap‐
              pended  to  this  intermediate  file, for inclusion in the final
              formatting passes.

       [4mpdf[24m$$[4m.tc[0m
              An intermediate [4mPostScript[24m file, in which  “Table  of  Contents”
              entries  are collected, to facilitate relocation before the body
              text, on ultimate output to the [4mGhostscript[24m postprocessor.

       [4mpdf[24m$$[4m.ps[0m
              An intermediate [4mPostScript[24m file, in which the body text is  col‐
              lected  prior  to ultimate output to the [4mGhostscript[24m postproces‐
              sor, in the proper sequence, [4mafter[24m [4mpdf[24m$$[4m.tc[24m.

[1mAuthors[0m
       [4mpdfroff[24m was written by Keith Marshall  ⟨keith.d.marshall@ntlworld.com⟩,
       who  maintains  it  at  his  [4mgroff‐pdfmark[24m OSDN site ⟨https://osdn.net/
       users/keith/pf/groff‐pdfmark/wiki/FrontPage⟩.  [4mgroff[24m’s version  may  be
       withdrawn in a future release.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       Since  [4mpdfroff[24m provides a superset of all [4mgroff[24m capabilities, the above
       manual, or its terser reference page, [4mgroff[24m(7) may also  be  considered
       definitive  references  to  all  [4mstandard[24m capabilities of [4mpdfroff[24m, with
       this document providing the reference to [4mpdfroff[24m’s extended features.

       While [4mpdfroff[24m imposes neither any restriction on, nor  any  requirement
       for,  the use of any specific [4mgroff[24m macro package, a number of supplied
       macro packages, and in particular those  associated  with  the  package
       [4mpdfmark.tmac[24m,  are  best  suited  for use with [4mpdfroff[24m as the preferred
       formatter.

       [4m/usr/share/doc/groff-1.23.0/pdf/pdfmark.pdf[0m
              “Portable Document Format Publishing with GNU [4mTroff[24m”,  by  Keith
              Marshall,  offers  detailed  documentation  on  the use of these
              packages.  This file, together with its source,  [4mpdfmark.ms[24m,  is
              part of the [4mgroff[24m distribution.

groff 1.23.0                      5 July 2023                       [4mpdfroff[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mpfbtops[24m(1)                  General Commands Manual                 [4mpfbtops[24m(1)

[1mName[0m
       pfbtops  -  translate  PostScript  Printer Font Binary files to Printer
       Font ASCII

[1mSynopsis[0m
       [1mpfbtops [22m[[4mpfb‐file[24m]

       [1mpfbtops --help[0m

       [1mpfbtops -v[0m
       [1mpfbtops --version[0m

[1mDescription[0m
       [4mpfbtops[24m translates a PostScript Type 1  font  in  Printer  Font  Binary
       (PFB)  format  to  Printer  Font ASCII (PFA) format, splitting overlong
       lines in text packets into smaller chunks.  If [4mpfb‐file[24m is omitted, the
       PFB file will be read from the standard input  stream.   The  PFA  font
       will  be  written  on the standard output stream.  PostScript fonts for
       MS‐DOS were historically supplied in PFB format.  Use of  a  PostScript
       Type 1 font with [4mgroff[24m requires conversion of its metrics (AFM file) to
       a [4mgroff[24m font description file; see [4mafmtodit[24m(1).

       The [1m--help [22moption displays a usage message, while [1m-v [22mand [1m--version [22mshow
       version information; all exit afterward.

[1mSee also[0m
       [4mgrops[24m(1), [4mgropdf[24m(1)

groff 1.23.0                      5 July 2023                       [4mpfbtops[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mpic[24m(1)                      General Commands Manual                     [4mpic[24m(1)

[1mName[0m
       pic - compile pictures for [4mtroff[24m or TeX

[1mSynopsis[0m
       [1mpic [22m[[1m-CnSU[22m] [[4mfile[24m ...]

       [1mpic -t [22m[[1m-cCSUz[22m] [[4mfile[24m ...]

       [1mpic --help[0m

       [1mpic -v[0m
       [1mpic --version[0m

[1mDescription[0m
       The  GNU implementation of [4mpic[24m is part of the [4mgroff[24m(1) document format‐
       ting system.  [4mpic[24m is a [4mtroff[24m(1) preprocessor that  translates  descrip‐
       tions  of  diagrammatic pictures embedded in [4mroff[24m(7) or TeX input files
       into the language understood by TeX or [4mtroff[24m.  It copies  the  contents
       of  each  [4mfile[24m to the standard output stream, except that lines between
       [1m.PS [22mand any of [1m.PE[22m, [1m.PF[22m, or [1m.PY [22mare interpreted as picture descriptions
       in the [4mpic[24m language.  End a [4mpic[24m picture with [1m.PE [22mto leave  the  drawing
       position  at the bottom of the picture, and with [1m.PF [22mor [1m.PY [22mto leave it
       at the top.  Normally, [4mpic[24m is not executed directly by  the  user,  but
       invoked  by  specifying the [1m-p [22moption to [4mgroff[24m(1).  If no [4mfile[24m operands
       are given on the command line, or if [4mfile[24m is “[1m-[22m”,  the  standard  input
       stream is read.

       It  is  the user’s responsibility to provide appropriate definitions of
       the [1mPS[22m, [1mPE[22m, and one or both of the [1mPF [22mand  [1mPY  [22mmacros.   When  a  macro
       package does not supply these, obtain simple definitions with the [4mgroff[0m
       option [1m-mpic[22m; these will center each picture.

       GNU [4mpic[24m supports [1mPY [22mas a synonym of [1mPF [22mto work around a name space col‐
       lision  with  the  [4mmm[24m  macro package, which defines [1mPF [22mas a page footer
       management macro.  Use [1mPF [22mpreferentially unless a similar problem faces
       your document.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-c     [22mBe  more compatible with [4mtpic[24m; implies [1m-t[22m.  Lines beginning with
              [1m\ [22mare not passed through transparently.  Lines beginning with  [1m.[0m
              are  passed through with the initial [1m. [22mchanged to [1m\[22m.  A line be‐
              ginning with [1m.ps [22mis given special treatment:  it  takes  an  op‐
              tional integer argument specifying the line thickness (pen size)
              in  milliinches;  a  missing argument restores the previous line
              thickness; the default line thickness  is  8  milliinches.   The
              line thickness thus specified takes effect only when a non‐nega‐
              tive  line  thickness  has  not  been  specified  by  use of the
              [1mthickness [22mattribute or by setting the [1mlinethick [22mvariable.

       [1m-C     [22mRecognize [1m.PS[22m, [1m.PE[22m, [1m.PF[22m, and [1m.PY [22meven when followed by a charac‐
              ter other than space or newline.

       [1m-n     [22mDon’t use [4mgroff[24m extensions to the [4mtroff[24m drawing commands.  Spec‐
              ify this option if a postprocessor you’re using doesn’t  support
              these  extensions,  described in [4mgroff_out[24m(5).  This option also
              causes [4mpic[24m not to use zero‐length lines to draw  dots  in  [4mtroff[0m
              mode.

       [1m-S     [22mOperate  in [4msafer[24m [4mmode;[24m [1msh [22mcommands are ignored.  This mode, en‐
              abled by default, can be useful when operating on  untrustworthy
              input.

       [1m-t     [22mProduce TeX output.

       [1m-U     [22mOperate in [4munsafe[24m [4mmode;[24m [1msh [22mcommands are interpreted.

       [1m-z     [22mIn TeX mode, draw dots using zero‐length lines.

       The following options supported by other versions of [4mpic[24m are ignored.

       [1m-D     [22mDraw  all  lines  using  the \D escape sequence.  GNU [4mpic[24m always
              does this.

       [1m-T [4m[22mdev[24m Generate output for the [4mtroff[24m device [4mdev[24m.  This  is  unnecessary
              because the [4mtroff[24m output generated by GNU [4mpic[24m is device‐indepen‐
              dent.

[1mUsage[0m
       This  section  primarily  discusses the differences between GNU [4mpic[24m and
       the Eighth Edition Research Unix version of AT&T [4mpic[24m (1985).   Many  of
       these differences also apply to later versions of AT&T [4mpic[24m.

   [1mTeX mode[0m
       TeX‐compatible output is produced when the [1m-t [22moption is specified.  You
       must use a TeX driver that supports [4mtpic[24m version 2 specials.  ([4mtpic[24m was
       a  fork  of  AT&T  [4mpic[24m by Tim Morgan of the University of California at
       Irvine that diverged from its source around 1984.  It is best known to‐
       day for lending its name to a group of [1m\special  [22mcommands  it  produced
       for TeX.)

       Lines  beginning  with [1m\ [22mare passed through transparently; a [1m% [22mis added
       to the end of the line to avoid unwanted spaces.  You  can  safely  use
       this  feature  to change fonts or the value of [1m\baselineskip[22m.  Anything
       else may well produce undesirable results; use at your  own  risk.   By
       default,  lines  beginning with a dot are not treated specially—but see
       the [1m-c [22moption.

       In TeX mode, [4mpic[24m will define a vbox called  [1m\graph  [22mfor  each  picture.
       Use GNU [4mpic[24m’s [1mfigname [22mcommand to change the name of the vbox.  You must
       print that vbox yourself using the command
              \centerline{\box\graph}
       for  instance.  Since the vbox has a height of zero (it is defined with
       [1m\vtop[22m) this will produce slightly more vertical space above the picture
       than below it;
              \centerline{\raise 1em\box\graph}
       would avoid this.  To give the vbox a positive height and  a  depth  of
       zero  (as used by LaTeX’s [4mgraphics.sty[24m, for example) define the follow‐
       ing macro in your document.
              \def\gpicbox#1{%
                \vbox{\unvbox\csname #1\endcsname\kern 0pt}}
       You can then simply say [1m\gpicbox{graph} [22minstead of [1m\box\graph[22m.

   [1mCommands[0m
       Several commands new to GNU [4mpic[24m accept delimiters, shown in their  syn‐
       opses  as braces [1m{ }[22m.  Nesting of braces is supported.  Any other char‐
       acters (except a space, tab, or newline) may be used as alternative de‐
       limiters, in which case the members of a given pair must be  identical.
       Strings  are recognized within delimiters of either kind; they may con‐
       tain the delimiter character or unbalanced braces.

       [1mfor [4m[22mvariable[24m [1m= [4m[22mexpr1[24m [1mto [4m[22mexpr2[24m [[1mby [22m[[1m*[22m][4mexpr3[24m] [1mdo [4m[22mX[24m [4mbody[24m [4mX[0m
              Set [4mvariable[24m to [4mexpr1[24m.  While the value of [4mvariable[24m is less than
              or equal to [4mexpr2[24m, do [4mbody[24m and increment [4mvariable[24m by  [4mexpr3[24m;  if
              [1mby  [22mis not given, increment [4mvariable[24m by 1.  If [4mexpr3[24m is prefixed
              by [1m* [22mthen [4mvariable[24m will instead be  multiplied  by  [4mexpr3[24m.   The
              value  of  [4mexpr3[24m can be negative for the additive case; [4mvariable[0m
              is then tested whether it is greater than  or  equal  to  [4mexpr2[24m.
              For  the  multiplicative  case, [4mexpr3[24m must be greater than zero.
              If the constraints aren’t met, the loop isn’t executed.   [4mX[24m  can
              be any character not occurring in [4mbody[24m.

       [1mif [4m[22mexpr[24m [1mthen [4m[22mX[24m [4mif‐true[24m [4mX[24m [[1melse [4m[22mY[24m [4mif‐false[24m [4mY[24m]
              Evaluate  [4mexpr[24m;  if it is non‐zero then do [4mif‐true[24m, otherwise do
              [4mif‐false[24m.  [4mX[24m can be any character not occurring in  [4mif‐true[24m.   [4mY[0m
              can be any character not occurring in [4mif‐false[24m.

       [1mprint [4m[22marg[24m ...
              Concatenate  and  write  arguments  to the standard error stream
              followed by a newline.  Each [4marg[24m must be an expression, a  posi‐
              tion, or text.  This is useful for debugging.

       [1mcommand [4m[22marg[24m ...
              Concatenate  arguments  and pass them as a line to [4mtroff[24m or TeX.
              Each [4marg[24m must be an expression, a position,  or  text.   [1mcommand[0m
              allows  the  values of [4mpic[24m variables to be passed to the format‐
              ter.  For example,
                     .PS
                     x = 14
                     command ".ds string x is " x "."
                     .PE
                     \*[string]
              produces
                     x is 14.
              when formatted with [4mtroff[24m.

       [1msh [4m[22mX[24m [4mcommand[24m [4mX[0m
              Pass [4mcommand[24m to a shell.

       [1mcopy "[4m[22mfilename[24m[1m"[0m
              Include [4mfilename[24m at this point in the file.

       [1mcopy [22m[[1m"[4m[22mfilename[24m[1m"[22m] [1mthru [4m[22mX[24m [4mbody[24m [4mX[24m [[1muntil [22m"[4mword[24m[1m"[22m]
       [1mcopy [22m[[1m"[4m[22mfilename[24m[1m"[22m] [1mthru [4m[22mmacro[24m [[1muntil [22m"[4mword[24m[1m"[22m]
              This construct does [4mbody[24m once for each  line  of  [4mfilename[24m;  the
              line  is split into blank‐delimited words, and occurrences of [1m$[4m[22mi[0m
              in [4mbody[24m, for [4mi[24m between 1 and 9, are replaced by the [4mi[24m‐th word of
              the line.  If [4mfilename[24m is not given, lines are  taken  from  the
              current input up to [1m.PE[22m.  If an [1muntil [22mclause is specified, lines
              will  be read only until a line the first word of which is [4mword[24m;
              that line will then be discarded.  [4mX[24m can be  any  character  not
              occurring in [4mbody[24m.  For example,
                     .PS
                     copy thru % circle at ($1,$2) % until "END"
                     1 2
                     3 4
                     5 6
                     END
                     box
                     .PE
              and
                     .PS
                     circle at (1,2)
                     circle at (3,4)
                     circle at (5,6)
                     box
                     .PE
              are  equivalent.  The commands to be performed for each line can
              also be taken from a macro defined earlier by giving the name of
              the macro as the argument to [1mthru[22m.  The argument after  [1mthru  [22mis
              looked up as a macro name first; if not defined, its first char‐
              acter is interpreted as a delimiter.

       [1mreset[0m
       [1mreset [4m[22mpvar1[24m[[1m,[22m] [4mpvar2[24m ...
              Reset  predefined  variables  [4mpvar1[24m,  [4mpvar2[24m ... to their default
              values; if no arguments are given, reset  all  predefined  vari‐
              ables  to their default values.  Variable names may be separated
              by commas, spaces, or both.  Assigning a  value  to  [1mscale  [22malso
              causes  all  predefined  variables that control dimensions to be
              reset to their default values times the new value of [1mscale[22m.

       [1mplot [4m[22mexpr[24m [[1m"[4m[22mtext[24m[1m"[22m]
              This is a text object which is constructed by using  [4mtext[24m  as  a
              format  string for sprintf with an argument of [4mexpr[24m.  If [4mtext[24m is
              omitted a format string of [1m"%g"  [22mis  used.   Attributes  can  be
              specified  in the same way as for a normal text object.  Be very
              careful that you specify an appropriate format string; [4mpic[24m  does
              only very limited checking of the string.  This is deprecated in
              favour of [1msprintf[22m.

       [4mvar[24m [1m:= [4m[22mexpr[0m
              This syntax resembles variable assignment with [1m= [22mexcept that [4mvar[0m
              must  already be defined, and [4mexpr[24m will be assigned to [4mvar[24m with‐
              out creating a variable local to the current  block.   (By  con‐
              trast,  [1m=  [22mdefines [4mvar[24m in the current block if it is not already
              defined there, and then changes the value in the  current  block
              only.)  For example,
                     [1m.PS[0m
                     [1mx = 3[0m
                     [1my = 3[0m
                     [1m[[0m
                     [1mx := 5[0m
                     [1my = 5[0m
                     [1m][0m
                     [1mprint x   y[0m
                     [1m.PE[0m
              writes
                     5 3
              to the standard error stream.

   [1mExpressions[0m
       The syntax for expressions has been significantly extended.

       [4mx[24m [1m^ [4m[22my[24m (exponentiation)
       [1msin([4m[22mx[24m[1m)[0m
       [1mcos([4m[22mx[24m[1m)[0m
       [1matan2([4m[22my[24m[1m, [4m[22mx[24m[1m)[0m
       [1mlog([4m[22mx[24m[1m) [22m(base 10)
       [1mexp([4m[22mx[24m[1m) [22m(base 10, i.e. 10^[4mx[24m)
       [1msqrt([4m[22mx[24m[1m)[0m
       [1mint([4m[22mx[24m[1m)[0m
       [1mrand() [22m(return a random number between 0 and 1)
       [1mrand([4m[22mx[24m[1m) [22m(return a random number between 1 and [4mx[24m; deprecated)
       [1msrand([4m[22mx[24m[1m) [22m(set the random number seed)
       [1mmax([4m[22me1[24m[1m, [4m[22me2[24m[1m)[0m
       [1mmin([4m[22me1[24m[1m, [4m[22me2[24m[1m)[0m
       [1m![4m[22me[0m
       [4me1[24m [1m&& [4m[22me2[0m
       [4me1[24m [1m|| [4m[22me2[0m
       [4me1[24m [1m== [4m[22me2[0m
       [4me1[24m [1m!= [4m[22me2[0m
       [4me1[24m [1m>= [4m[22me2[0m
       [4me1[24m [1m> [4m[22me2[0m
       [4me1[24m [1m<= [4m[22me2[0m
       [4me1[24m [1m< [4m[22me2[0m
       [1m"[4m[22mstr1[24m[1m" == "[4m[22mstr2[24m[1m"[0m
       [1m"[4m[22mstr1[24m[1m" != "[4m[22mstr2[24m[1m"[0m

       String comparison expressions must be parenthesised in some contexts to
       avoid ambiguity.

   [1mOther changes[0m
       A  bare  expression, [4mexpr[24m, is acceptable as an attribute; it is equiva‐
       lent to [4mdir[24m [4mexpr[24m, where [4mdir[24m is the current direction.  For example

              [1mline 2i[0m

       means draw a line 2 inches long in the current direction.  The ‘i’  (or
       ‘I’)  character  is  ignored;  to use another measurement unit, set the
       [4mscale[24m variable to an appropriate value.

       The maximum width and height of the picture are taken  from  the  vari‐
       ables [1mmaxpswid [22mand [1mmaxpsht[22m.  Initially, these have values 8.5 and 11.

       Scientific notation is allowed for numbers.  For example

              [1mx = 5e-2[0m

       Text attributes can be compounded.  For example,

              [1m"foo" above ljust[0m

       is valid.

       There  is  no  limit to the depth to which blocks can be examined.  For
       example,

              [A: [B: [C: box ]]] with .A.B.C.sw at 1,2
              circle at last [].A.B.C

       is acceptable.

       Arcs now have compass points determined by the circle of which the  arc
       is a part.

       Circles,  ellipses,  and  arcs  can  be  dotted or dashed.  In TeX mode
       splines can be dotted or dashed also.

       Boxes can have rounded corners.  The [1mrad [22mattribute specifies the radius
       of the quarter‐circles at each corner.  If no [1mrad [22mor [1mdiam [22mattribute  is
       given, a radius of [1mboxrad [22mis used.  Initially, [1mboxrad [22mhas a value of 0.
       A box with rounded corners can be dotted or dashed.

       Boxes  can have slanted sides.  This effectively changes the shape of a
       box from a rectangle to an arbitrary parallelogram.  The  [1mxslanted  [22mand
       [1myslanted [22mattributes specify the x and y offset of the box’s upper right
       corner from its default position.

       The [1m.PS [22mline can have a second argument specifying a maximum height for
       the  picture.   If the width of zero is specified the width will be ig‐
       nored in computing the scaling factor for the picture.   GNU  [4mpic[24m  will
       always  scale  a picture by the same amount vertically as well as hori‐
       zontally.  This is different from DWB 2.0 [4mpic[24m which may scale a picture
       by a different amount vertically than horizontally if a height is spec‐
       ified.

       Each text object has an invisible box associated with it.  The  compass
       points  of  a text object are determined by this box.  The implicit mo‐
       tion associated with the object is also determined by  this  box.   The
       dimensions  of this box are taken from the width and height attributes;
       if the width attribute is not supplied then the width will be taken  to
       be  [1mtextwid[22m;  if  the  height attribute is not supplied then the height
       will be taken to be the number of text strings associated with the  ob‐
       ject times [1mtextht[22m.  Initially, [1mtextwid [22mand [1mtextht [22mhave a value of 0.

       In  (almost  all) places where a quoted text string can be used, an ex‐
       pression of the form

              [1msprintf("[4m[22mformat[24m[1m", [4m[22marg[24m[1m, [22m...[1m)[0m

       can also be used; this will produce the arguments  formatted  according
       to [4mformat[24m, which should be a string as described in [4mprintf[24m(3) appropri‐
       ate for the number of arguments supplied.  Only the modifiers “[1m#[22m”, “[1m-[22m”,
       “[1m+[22m”,  and  “  ” [space]), a minimum field width, an optional precision,
       and the conversion specifiers [1m%e[22m, [1m%E[22m, [1m%f[22m, [1m%g[22m, [1m%G[22m, and [1m%% [22mare supported.

       The thickness of the lines used to draw objects is  controlled  by  the
       [1mlinethick  [22mvariable.   This  gives the thickness of lines in points.  A
       negative value means use the default thickness:  in  TeX  output  mode,
       this  means  use  a thickness of 8 milliinches; in TeX output mode with
       the [1m-c [22moption, this means use  the  line  thickness  specified  by  [1m.ps[0m
       lines; in [4mtroff[24m output mode, this means use a thickness proportional to
       the pointsize.  A zero value means draw the thinnest possible line sup‐
       ported  by  the output device.  Initially, it has a value of -1.  There
       is also a [1mthick[22m[[1mness[22m] attribute.  For example,

              [1mcircle thickness 1.5[0m

       would draw a circle using a line with a thickness of 1.5  points.   The
       thickness  of lines is not affected by the value of the [1mscale [22mvariable,
       nor by the width or height given in the [1m.PS [22mline.

       Boxes (including boxes with rounded corners or slanted sides),  circles
       and  ellipses  can  be  filled by giving them an attribute of [1mfill[22m[[1med[22m].
       This takes an optional argument of an expression with a value between 0
       and 1; 0 will fill it with white, 1 with black, values in between  with
       a  proportionally gray shade.  A value greater than 1 can also be used:
       this means fill with the shade of gray that is currently being used for
       text and lines.  Normally this will be black, but  output  devices  may
       provide  a  mechanism for changing this.  Without an argument, then the
       value of the variable [1mfillval [22mwill be  used.   Initially,  this  has  a
       value  of  0.5.  The invisible attribute does not affect the filling of
       objects.  Any text associated with a filled object will be added  after
       the  object  has  been filled, so that the text will not be obscured by
       the filling.

       Additional modifiers are available to draw colored objects:  [1moutline[22m[[1md[22m]
       sets  the color of the outline, [1mshaded [22mthe fill color, and [1mcolo[22m[[1mu[22m][1mr[22m[[1med[22m]
       sets both.  All expect a  subsequent  string  argument  specifying  the
       color.
              circle shaded "green" outline "black"
       Color  is  not  yet  supported  in  TeX  mode.  Device macro files like
       [4mps.tmac[24m declare color names; you can define additional  ones  with  the
       [1mdefcolor [22mrequest (see [4mgroff[24m(7)).

       To  change  the  name  of the vbox in TeX mode, set the pseudo‐variable
       [1mfigname [22m(which is actually a specially parsed command)  within  a  pic‐
       ture.  Example:

              [1m.PS[0m
              [1mfigname = foobar;[0m
              [1m...[0m
              [1m.PE[0m

       The picture is then available in the box [1m\foobar[22m.

       [4mpic[24m  assumes  that  at  the  beginning of a picture both glyph and fill
       color are set to the default value.

       Arrow heads will be drawn as solid triangles if the variable  [1marrowhead[0m
       is  non‐zero  and  either  TeX mode is enabled or the [1m-n [22moption has not
       been given.  Initially, [1marrowhead [22mhas a value of 1.  Solid arrow  heads
       are always filled with the current outline color.

       The [4mtroff[24m output of [4mpic[24m is device‐independent.  The [1m-T [22moption is there‐
       fore  redundant.   All  numbers  are taken to be in inches; numbers are
       never interpreted to be in [4mtroff[24m machine units.

       Objects can have an [1maligned [22mattribute.  This  will  only  work  if  the
       postprocessor  is  [4mgrops[24m(1)  or [4mgropdf[24m(1).  Any text associated with an
       object having the [1maligned [22mattribute will be rotated about the center of
       the object so that it is aligned in the direction from the start  point
       to  the end point of the object.  This attribute will have no effect on
       objects whose start and end points are coincident.

       In places where [4mn[24m[1mth [22mis allowed, [1m'[4m[22mexpr[24m[1m'th [22mis also allowed.  “[1m'th[22m“  is  a
       single  token: no space is allowed between the apostrophe and the “[1mth[22m”.
       For example,

              for i = 1 to 4 do {
                 line from 'i'th box.nw to 'i+1'th box.se
              }

[1mConversion[0m
       To obtain a stand‐alone picture from a [4mpic[24m file, enclose your [4mpic[24m  code
       with  [1m.PS [22mand [1m.PE [22mrequests; [4mroff[24m configuration commands may be added at
       the beginning of the file, but no [4mroff[24m text.

       It is necessary to feed this file into [4mgroff[24m without  adding  any  page
       information,  so you must check which [1m.PS [22mand [1m.PE [22mrequests are actually
       called.  For example, the [4mmm[24m macro package adds a page number, which is
       very annoying.  At the moment, calling standard [4mgroff[24m without any macro
       package works.  Alternatively, you can define your own requests,  e.g.,
       to do nothing:

              .de PS
              ..
              .de PE
              ..

       [4mgroff[24m  itself  does  not  provide direct conversion into other graphics
       file formats.  But there are lots of possibilities if you first  trans‐
       form  your picture into PostScript® format using the [4mgroff[24m option [1m-Tps[22m.
       Since this [4mps[24m‐file lacks BoundingBox information it is not very  useful
       by  itself,  but  it may be fed into other conversion programs, usually
       named [1mps2[4m[22mother[24m or [1mpsto[4m[22mother[24m or the like.  Moreover, the PostScript  in‐
       terpreter  Ghostscript ([4mgs[24m(1)) has built‐in graphics conversion devices
       that are called with the option

              [1mgs -sDEVICE=[4m[22m<devname>[0m

       Call

              [1mgs --help[0m

       for a list of the available devices.

       An alternative may be to use the [1m-Tpdf [22moption to convert  your  picture
       directly  into  [1mPDF  [22mformat.   The MediaBox of the file produced can be
       controlled by passing a [1m-P-p [22mpapersize to [4mgroff[24m.

       As the Encapsulated PostScript File Format [1mEPS [22mis getting more and more
       important, and the conversion wasn’t regarded trivial in the  past  you
       might  be  interested  to  know  that  there is a conversion tool named
       [4mps2eps[24m which does the right job.  It  is  much  better  than  the  tool
       [4mps2epsi[24m packaged with [4mgs[24m.

       For  bitmapped  graphic  formats, you should use [4mpstopnm[24m; the resulting
       (intermediate) [4mpnm[24m(5) file can  be  then  converted  to  virtually  any
       graphics format using the tools of the [1mnetpbm [22mpackage.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/pic.tmac[0m
              offers simple definitions of the [1mPS[22m, [1mPE[22m, [1mPF[22m, and [1mPY [22mmacros.

[1mBugs[0m
       Characters  that  are invalid as input to GNU [4mtroff[24m (see the [4mgroff[24m Tex‐
       info manual or [4mgroff_char[24m(7) for a list) are rejected even in TeX mode.

       The interpretation of [1mfillval [22mis incompatible with  the  [4mpic[24m  in  Tenth
       Edition Research Unix, which interprets 0 as black and 1 as white.

[1mSee also[0m
       [4m/usr/share/doc/groff-1.23.0/pic.ps[0m
              “Making  Pictures with GNU pic”, by Eric S. Raymond.  This file,
              together with its source, [4mpic.ms[24m, is part of the [4mgroff[24m distribu‐
              tion.

       “PIC—A Graphics Language for Typesetting: User  Manual”,  by  Brian  W.
       Kernighan,  1984  (revised 1991), AT&T Bell Laboratories Computing Sci‐
       ence Technical Report No. 116

       [4mps2eps[24m is  available  from  CTAN  mirrors,  e.g.,  ⟨ftp://ftp.dante.de/
       tex-archive/support/ps2eps/⟩

       W. Richard Stevens, [4mTurning[24m [4mPIC[24m [4minto[24m [4mHTML[24m ⟨http://www.kohala.com/start/
       troff/pic2html.html⟩

       W.  Richard  Stevens,  [4mExamples[24m  [4mof[24m  pic [4mMacros[24m ⟨http://www.kohala.com/
       start/troff/pic.examples.ps⟩

       [4mtroff[24m(1),   [4mgroff_out[24m(5),   [4mtex[24m(1),   [4mgs[24m(1),   [4mps2eps[24m(1),   [4mpstopnm[24m(1),
       [4mps2epsi[24m(1), [4mpnm[24m(5)

groff 1.23.0                      5 July 2023                           [4mpic[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mpic2graph[24m(1)                General Commands Manual               [4mpic2graph[24m(1)

[1mName[0m
       pic2graph - convert a [4mpic[24m diagram into a cropped image

[1mSynopsis[0m
       [1mpic2graph [22m[[1m-unsafe[22m] [[1m-format [4m[22moutput‐format[24m] [[1m-eqn [4m[22mdelimiters[24m] [[4mconvert‐[0m
                 [4margument[24m ...]

       [1mpic2graph --help[0m

       [1mpic2graph -v[0m
       [1mpic2graph --version[0m

[1mDescription[0m
       [4mpic2graph[24m  reads a [4mpic[24m(1) program from the standard input and writes an
       image file, by default in Portable Network Graphics  (PNG)  format,  to
       the  standard  output.  It furthermore translates [4meqn[24m(1) constructs, so
       it can be used for generating images of mathematical formulae.

       The input PIC code should [4mnot[24m be  wrapped  with  the  [1m.PS  [22mand  [1m.PE[22m/[1m.PF[0m
       macros that normally guard it within [4mgroff[24m(1) documents.

       Arguments  not recognized by [4mpic2graph[24m are passed to the ImageMagick or
       GraphicsMagick program [4mconvert[24m(1).  By specifying these, you  can  give
       your  image  a  border, set the image’s pixel density, or perform other
       useful transformations.

       The output image is clipped using [4mconvert[24m’s [1m-trim [22moption to the  small‐
       est possible bounding box that contains all the black pixels.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-eqn [4m[22mdelimiters[0m
              Use [4mdelimiters[24m as the opening and closing  characters  that  de‐
              limit  [4meqn[24m directives; the default is “$$”.  The option argument
              [4mdelimiters[24m should be a two‐character string, but an empty string
              ("") is accepted as a directive to disable [4meqn[24m processing.

       [1m-format [4m[22moutput‐format[0m
              Write the image in [4moutput‐format[24m, which must  be  understood  by
              [4mconvert[24m; the default is PNG.

       [1m-unsafe[0m
              Run [4mgroff[24m in [4munsafe[24m mode, enabling the PIC command [1msh [22mto execute
              arbitrary  Unix  shell commands.  The [4mgroff[24m default is to forbid
              this.

[1mEnvironment[0m
       [4mGROFF_TMPDIR[0m
       [4mTMPDIR[0m
       [4mTMP[0m
       [4mTEMP[24m   These environment variables are searched in the given  order  to
              determine  the  directory where temporary files will be created.
              If none are set, [4m/tmp[24m is used.

[1mAuthors[0m
       [4mpic2graph[24m was written by Eric S. Raymond ⟨esr@thyrsus.com⟩, based on  a
       recipe by W. Richard Stevens.

[1mSee also[0m
       W. Richard Stevens, [4mTurning[24m [4mPIC[24m [4minto[24m [4mHTML[24m ⟨http://www.kohala.com/start/
       troff/pic2html.html⟩

       [4meqn2graph[24m(1), [4mgrap2graph[24m(1), [4mpic[24m(1), [4meqn[24m(1), [4mgroff[24m(1), [4mconvert[24m(1)

groff 1.23.0                      5 July 2023                     [4mpic2graph[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mpreconv[24m(1)                  General Commands Manual                 [4mpreconv[24m(1)

[1mName[0m
       preconv - prepare files for typesetting with [4mgroff[0m

[1mSynopsis[0m
       [1mpreconv [22m[[1m-dr[22m] [[1m-D [4m[22mfallback‐encoding[24m] [[1m-e [4m[22mencoding[24m] [[4mfile[24m ...]

       [1mpreconv -h[0m
       [1mpreconv --help[0m

       [1mpreconv -v[0m
       [1mpreconv --version[0m

[1mDescription[0m
       [4mpreconv[24m  reads  each  [4mfile[24m,  converts  its encoded characters to a form
       [4mtroff[24m(1) can interpret, and sends the result  to  the  standard  output
       stream.   Currently, this means that code points in the range 0–127 (in
       US‐ASCII, ISO 8859, or Unicode) remain as‐is and the remainder are con‐
       verted to the [4mgroff[24m special character form “[1m\[u[4m[22mXXXX[24m[1m][22m”, where [4mXXXX[24m is  a
       hexadecimal  number  of  four  to six digits corresponding to a Unicode
       code point.  By default, [4mpreconv[24m also inserts a [4mroff[24m [1m.lf [22mrequest at the
       beginning of each [4mfile[24m, identifying it for the benefit  of  later  pro‐
       cessing  (including diagnostic messages); the [1m-r [22moption suppresses this
       behavior.

       In typical usage scenarios, [4mpreconv[24m need not be run  directly;  instead
       it  should  be  invoked with the [1m-k [22mor [1m-K [22moptions of [4mgroff[24m.  If no [4mfile[0m
       operands are given on the command line, or if [4mfile[24m is “[1m-[22m”, the standard
       input stream is read.

       [4mpreconv[24m tries to find the input encoding with the following  algorithm,
       stopping at the first success.

       1.  If the input encoding has been explicitly specified with option [1m-e[22m,
           use it.

       2.  If  the  input starts with a Unicode Byte Order Mark, determine the
           encoding as UTF‐8, UTF‐16, or UTF‐32 accordingly.

       3.  If the input stream is seekable, check the first and  second  input
           lines  for  a  recognized GNU Emacs file‐local variable identifying
           the character encoding, here referred to as the  “coding  tag”  for
           brevity.  If found, use it.

       4.  If  the  input  stream  is seekable, and if the [4muchardet[24m library is
           available on the system, use it to try to infer the encoding of the
           file.

       5.  If the [1m-D [22moption specifies an encoding, use it.

       6.  Use the encoding specified by the current locale ([4mLC_CTYPE[24m), unless
           the locale is “C”, “POSIX”, or empty, in which case assume  Latin‐1
           (ISO 8859‐1).

       The  coding tag and [4muchardet[24m methods in the above procedure rely upon a
       seekable input stream; when [4mpreconv[24m reads from a pipe,  the  stream  is
       not  seekable,  and  these detection methods are skipped.  If character
       encoding detection of your input files is unreliable, arrange  for  one
       of the other methods to succeed by using [4mpreconv[24m’s [1m-D [22mor [1m-e [22moptions, or
       by  configuring  your  locale  appropriately.   [4mgroff[24m  also  supports a
       [4mGROFF_ENCODING[24m environment variable, which can be overridden by its  [1m-K[0m
       option.   Valid  values for (or parameters to) all of these are enumer‐
       ated in the lists of recognized coding tags in the next subsection, and
       are further influenced by [4miconv[24m library support.

   [1mCoding tags[0m
       Text editors that support more than a single  character  encoding  need
       tags  within  the input files to mark the file’s encoding.  While it is
       possible to guess the right input encoding with the help of  heuristics
       that  are  reliable for a preponderance of natural language texts, they
       are not absolutely reliable.  Heuristics can fail on  inputs  that  are
       too short or don’t represent a natural language.

       Consequently,  [4mpreconv[24m  supports  the  coding  tag  convention  used by
       GNU Emacs (with some restrictions).  This notation appears in specially
       marked regions of an input file designated for “file‐local variables”.

       [4mpreconv[24m interprets the following syntax if it occurs in a [4mroff[24m  comment
       in the first or second line of the input file.  Both “\"” and “\#” com‐
       ment  forms are recognized, but the control (or no‐break control) char‐
       acter must be the default and must begin the line.  Similarly, the  es‐
       cape character must be the default.
              [1m-*- [22m[...[1m;[22m] [1mcoding: [4m[22mencoding[24m[[1m; [22m...] [1m-*-[0m

       The  only  variable  [4mpreconv[24m interprets is “coding”, which can take the
       values listed below.

       The following list comprises all MIME “charset” parameter values recog‐
       nized, case‐insensitively, by [4mpreconv[24m.
              big5, cp1047, euc-jp, euc-kr,  gb2312,  iso-8859-1,  iso-8859-2,
              iso-8859-5,  iso-8859-7,  iso-8859-9,  iso-8859-13, iso-8859-15,
              koi8-r, us-ascii, utf-8, utf-16, utf-16be, utf-16le

       In addition, the following list of other  coding  tags  is  recognized,
       each of which is mapped to an appropriate value from the list above.
              ascii,  chinese-big5,  chinese-euc,  chinese-iso-8bit,  cn-big5,
              cn-gb,     cn-gb-2312,     cp878,     csascii,      csisolatin1,
              cyrillic-iso-8bit,  cyrillic-koi8, euc-china, euc-cn, euc-japan,
              euc-japan-1990,   euc-korea,   greek-iso-8bit,   iso-10646/utf8,
              iso-10646/utf-8,    iso-latin-1,    iso-latin-2,    iso-latin-5,
              iso-latin-7, iso-latin-9, japanese-euc, japanese-iso-8bit, jis8,
              koi8, korean-euc,  korean-iso-8bit,  latin-0,  latin1,  latin-1,
              latin-2,  latin-5,  latin-7,  latin-9,  mule-utf-8, mule-utf-16,
              mule-utf-16be,   mule-utf-16-be,   mule-utf-16be-with-signature,
              mule-utf-16le,   mule-utf-16-le,   mule-utf-16le-with-signature,
              utf8,            utf-16-be,            utf-16-be-with-signature,
              utf-16be-with-signature,   utf-16-le,  utf-16-le-with-signature,
              utf-16le-with-signature

       Trailing “-dos”, “-unix”, and “-mac” suffixes on coding tags (which in‐
       dicate the end‐of‐line convention used in the file) are disregarded for
       the purpose of comparison with the above tags.

   [4m[1miconv[24m support[0m
       While [4mpreconv[24m recognizes all of the coding tags listed above, it is ca‐
       pable on its own of interpreting only three  encodings:  Latin‐1,  code
       page  1047,  and UTF‐8.  If [4miconv[24m support is configured at compile time
       and available at run time, all others are passed to [4miconv[24m library func‐
       tions, which may recognize many additional encoding strings.  The  com‐
       mand “[1mpreconv -v[22m” discloses whether [4miconv[24m support is configured.

       The use of [4miconv[24m means that characters in the input that encode invalid
       code  points for that encoding may be dropped from the output stream or
       mapped to the Unicode replacement character (U+FFFD).  Compare the fol‐
       lowing examples using the input “café” (note the “e” with an acute  ac‐
       cent), which due to its short length challenges inference of the encod‐
       ing used.
              printf 'caf\351\n' | LC_ALL=en_US.UTF-8 preconv
              printf 'caf\351\n' | preconv -e us-ascii
              printf 'caf\351\n' | preconv -e latin-1
       The  fate  of  the  accented  “e”  differs in each case.  In the first,
       [4muchardet[24m fails to detect an encoding (though the library on your system
       may behave differently) and [4mpreconv[24m falls back to the locale  settings,
       where  octal 351 starts an incomplete UTF‐8 sequence and results in the
       Unicode replacement character.  In the  second,  it  is  not  a  repre‐
       sentable  character  in  the declared input encoding of US‐ASCII and is
       discarded by [4miconv[24m.  In the last, it is correctly detected and mapped.

   [1mLimitations[0m
       [4mpreconv[24m cannot perform any transformation on input that it cannot  see.
       Examples  include files that are interpolated by preprocessors that run
       subsequently, including  [4msoelim[24m(1);  files  included  by  [4mtroff[24m  itself
       through  “[1mso[22m”  and  similar  requests; and string definitions passed to
       [4mtroff[24m through its [1m-d [22mcommand‐line option.

       [4mpreconv[24m assumes that its input uses the  default  escape  character,  a
       backslash [1m\[22m, and writes special character escape sequences accordingly.

[1mOptions[0m
       [1m-h [22mand [1m--help [22mdisplay a usage message, while [1m-v [22mand [1m--version [22mshow ver‐
       sion information; all exit afterward.

       [1m-d     [22mEmit debugging messages to the standard error stream.

       [1m-D [4m[22mfallback‐encoding[0m
              Report [4mfallback‐encoding[24m if all detection methods fail.

       [1m-e [4m[22mencoding[0m
              Skip detection and assume [4mencoding[24m; see [4mgroff[24m’s [1m-K [22moption.

       [1m-r     [22mWrite files “raw”; do not add [1m.lf [22mrequests.

[1mSee also[0m
       [4mgroff[24m(1), [4miconv[24m(3), [4mlocale[24m(7)

groff 1.23.0                      5 July 2023                       [4mpreconv[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mrefer[24m(1)                    General Commands Manual                   [4mrefer[24m(1)

[1mName[0m
       refer - process bibliographic references for [4mgroff[0m

[1mSynopsis[0m
       [1mrefer [22m[[1m-bCenPRS[22m] [[1m-a [4m[22mn[24m] [[1m-B [4m[22mfield[24m[1m.[4m[22mmacro[24m] [[1m-c [4m[22mfields[24m] [[1m-f [4m[22mn[24m] [[1m-i [4m[22mfields[24m]
             [[1m-k [4m[22mfield[24m] [[1m-l [4m[22mrange‐expression[24m] [[1m-p [4m[22mdatabase‐file[24m] [[1m-s [4m[22mfields[24m]
             [[1m-t [4m[22mn[24m] [[4mfile[24m ...]

       [1mrefer --help[0m

       [1mrefer -v[0m
       [1mrefer --version[0m

[1mDescription[0m
       The  GNU  implementation of [4mrefer[24m is part of the [4mgroff[24m(1) document for‐
       matting system.  [4mrefer[24m is a [4mtroff[24m(1) preprocessor that prepares bibilo‐
       graphic citations by looking up keywords specified in a  [4mroff[24m(7)  input
       document,  obviating  the need to type such annotations, and permitting
       the citation style in formatted output to be altered independently  and
       systematically.   It  copies  the contents of each [4mfile[24m to the standard
       output stream, except that it interprets lines between [1m.[ [22mand [1m.] [22mas ci‐
       tations to be translated into [4mgroff[24m input, and lines  between  [1m.R1  [22mand
       [1m.R2  [22mas instructions regarding how citations are to be processed.  Nor‐
       mally, [4mrefer[24m is not executed directly by the user, but invoked by spec‐
       ifying the [1m-R [22moption to [4mgroff[24m(1).  If no [4mfile[24m operands are given on the
       command line, or if [4mfile[24m is “[1m-[22m”, the standard input stream is read.

       Each citation specifies a reference.  The citation can specify a refer‐
       ence that is contained in a bibliographic database by giving a  set  of
       keywords that only that reference contains.  Alternatively it can spec‐
       ify a reference by supplying a database record in the citation.  A com‐
       bination of these alternatives is also possible.

       For  each  citation,  [4mrefer[24m  can produce a mark in the text.  This mark
       consists of some label which can be separated from the  text  and  from
       other  labels  in  various  ways.   For  each reference it also outputs
       [4mgroff[24m(7) language commands that can be used by a macro package to  pro‐
       duce a formatted reference for each citation.  The output of [4mrefer[24m must
       therefore  be processed using a suitable macro package, such as [4mme[24m, [4mmm[24m,
       [4mmom[24m, or [4mms[24m.  The commands to format a citation’s reference can be  out‐
       put  immediately  after  the citation, or the references may be accumu‐
       lated, and the commands output at some later point.  If the  references
       are  accumulated,  then  multiple  citations of the same reference will
       produce a single formatted reference.

       The interpretation of lines between [1m.R1 [22mand [1m.R2 [22mas  prepreocessor  com‐
       mands  is a feature of GNU [4mrefer[24m.  Documents making use of this feature
       can still be processed by AT&T [4mrefer[24m just by adding the lines
              .de R1
              .ig R2
              ..
       to the beginning of the document.  This will cause [4mtroff[24m(1)  to  ignore
       everything  between  [1m.R1 [22mand [1m.R2[22m.  The effect of some commands can also
       be achieved by options.  These options are supported mainly for compat‐
       ibility with AT&T [4mrefer[24m.  It is usually more  convenient  to  use  com‐
       mands.

       [4mrefer[24m  generates  [1m.lf  [22mrequests  so that file names and line numbers in
       messages produced by commands that read [4mrefer[24m output will  be  correct;
       it also interprets lines beginning with [1m.lf [22mso that file names and line
       numbers in the messages and [1m.lf [22mlines that it produces will be accurate
       even if the input has been preprocessed by a command such as [4msoelim[24m(1).

   [1mBibliographic databases[0m
       The  bibliographic  database is a text file consisting of records sepa‐
       rated by one or more blank lines.  Within each record fields start with
       a [1m% [22mat the beginning of a line.  Each field has a  one  character  name
       that immediately follows the [1m%[22m.  It is best to use only upper and lower
       case  letters for the names of fields.  The name of the field should be
       followed by exactly one space, and then by the contents of  the  field.
       Empty fields are ignored.  The conventional meaning of each field is as
       follows:

       [1m%A     [22mThe  name  of  an author.  If the name contains a suffix such as
              “Jr.”, it should be separated from the last  name  by  a  comma.
              There can be multiple occurrences of the [1m%A [22mfield.  The order is
              significant.   It is a good idea always to supply an [1m%A [22mfield or
              a [1m%Q [22mfield.

       [1m%B     [22mFor an article that is part of a book, the title of the book.

       [1m%C     [22mThe place (city) of publication.

       [1m%D     [22mThe date of publication.  The year should be specified in  full.
              If  the  month  is specified, the name rather than the number of
              the month should be used, but only the first three  letters  are
              required.  It is a good idea always to supply a [1m%D [22mfield; if the
              date  is  unknown,  a  value  such as [1min press [22mor [1munknown [22mcan be
              used.

       [1m%E     [22mFor an article that is part of a book, the name of an editor  of
              the  book.  Where the work has editors and no authors, the names
              of the editors should be given as [1m%A [22mfields  and  “[1m,  (ed.)[22m”  or
              “[1m, (eds.)[22m” should be appended to the last author.

       [1m%G     [22mU.S. government ordering number.

       [1m%I     [22mThe publisher (issuer).

       [1m%J     [22mFor an article in a journal, the name of the journal.

       [1m%K     [22mKeywords to be used for searching.

       [1m%L     [22mLabel.

       [1m%N     [22mJournal issue number.

       [1m%O     [22mOther  information.   This  is usually printed at the end of the
              reference.

       [1m%P     [22mPage number.  A range of pages can be specified as [4mm[24m[1m-[4m[22mn[24m.

       [1m%Q     [22mThe name of the author, if the author is  not  a  person.   This
              will  only be used if there are no [1m%A [22mfields.  There can only be
              one [1m%Q [22mfield.

       [1m%R     [22mTechnical report number.

       [1m%S     [22mSeries name.

       [1m%T     [22mTitle.  For an article in a book or journal, this should be  the
              title of the article.

       [1m%V     [22mVolume number of the journal or book.

       [1m%X     [22mAnnotation.

       For  all  fields except [1m%A [22mand [1m%E[22m, if there is more than one occurrence
       of a particular field in a record, only the last  such  field  will  be
       used.

       If  accent strings are used, they should follow the character to be ac‐
       cented.  This means that an [4mms[24m document must call the [1m.AM [22mmacro when it
       initializes.  Accent strings should not be quoted:  use  one  [1m\  [22mrather
       than  two.   Accent strings are an obsolescent feature of the [4mme[24m and [4mms[0m
       macro packages; modern documents should use [4mgroff[24m special character es‐
       cape sequences instead; see [4mgroff_char[24m(7).

   [1mCitations[0m
       Citations have a characteristic format.
              [1m.[[4m[22mopening‐text[0m
              [4mflags[24m [4mkeywords[0m
              [4mfields[0m
              [1m.][4m[22mclosing‐text[0m

       The [4mopening‐text[24m, [4mclosing‐text[24m,  and  [4mflags[24m  components  are  optional.
       Only one of the [4mkeywords[24m and [4mfields[24m components need be specified.

       The [4mkeywords[24m component says to search the bibliographic databases for a
       reference  that  contains all the words in [4mkeywords[24m.  It is an error if
       more than one reference is found.

       The [4mfields[24m components specifies additional fields to replace or supple‐
       ment those specified in the reference.  When references are being accu‐
       mulated and the [4mkeywords[24m component is non‐empty, then additional fields
       should be specified only on the first occasion that a particular refer‐
       ence is cited, and will apply to all citations of that reference.

       The [4mopening‐text[24m and [4mclosing‐text[24m components specify strings to be used
       to bracket the label instead of those in the [1mbracket-label [22mcommand.  If
       either of these components is non‐empty, the strings specified  in  the
       [1mbracket-label  [22mcommand  will  not be used; this behavior can be altered
       using the [1m[ [22mand [1m] [22mflags.  Leading and trailing spaces  are  significant
       for these components.

       The  [4mflags[24m  component  is a list of non‐alphanumeric characters each of
       which modifies the treatment of this particular citation.   AT&T  [4mrefer[0m
       will  treat these flags as part of the keywords and so will ignore them
       since they are non‐alphanumeric.  The  following  flags  are  currently
       recognized.

       [1m#      [22mUse  the  label specified by the [1mshort-label [22mcommand, instead of
              that specified by the [1mlabel [22mcommand.  If no short label has been
              specified, the normal label will be used.  Typically  the  short
              label  is  used with author‐date labels and consists of only the
              date and possibly a disambiguating letter; the “[1m#[22m”  is  supposed
              to be suggestive of a numeric type of label.

       [1m[      [22mPrecede  [4mopening‐text[24m  with  the  first  string specified in the
              [1mbracket-label [22mcommand.

       [1m]      [22mFollow [4mclosing‐text[24m with the  second  string  specified  in  the
              [1mbracket-label [22mcommand.

       An  advantage  of  using  the  [1m[  [22mand [1m] [22mflags rather than including the
       brackets in [4mopening‐text[24m and [4mclosing‐text[24m is that you  can  change  the
       style   of   bracket   used  in  the  document  just  by  changing  the
       [1mbracket-label [22mcommand.  Another is that sorting and  merging  of  cita‐
       tions will not necessarily be inhibited if the flags are used.

       If  a label is to be inserted into the text, it will be attached to the
       line preceding the [1m.[ [22mline.  If there is no such line,  then  an  extra
       line will be inserted before the [1m.[ [22mline and a warning will be given.

       There  is  no special notation for making a citation to multiple refer‐
       ences.  Just use a sequence  of  citations,  one  for  each  reference.
       Don’t put anything between the citations.  The labels for all the cita‐
       tions  will  be attached to the line preceding the first citation.  The
       labels may also be sorted or merged.  See the description of the [1m<> [22mla‐
       bel    expression,    and    of    the     [1msort-adjacent-labels     [22mand
       [1mabbreviate-label-ranges  [22mcommands.   A  label will not be merged if its
       citation has a non‐empty [4mopening‐text[24m or  [4mclosing‐text[24m.   However,  the
       labels for a citation using the [1m] [22mflag and without any [4mclosing‐text[24m im‐
       mediately followed by a citation using the [1m[ [22mflag and without any [4mopen‐[0m
       [4ming‐text[24m  may  be  sorted  and  merged even though the first citation’s
       [4mopening‐text[24m or the second citation’s [4mclosing‐text[24m is  non‐empty.   (If
       you wish to prevent this, use the dummy character escape sequence [1m\& [22mas
       the first citation’s [4mclosing‐text[24m.)

   [1mCommands[0m
       Commands are contained between lines starting with [1m.R1 [22mand [1m.R2[22m.  Recog‐
       nition  of  these  lines can be prevented by the [1m-R [22moption.  When a [1m.R1[0m
       line is recognized any accumulated references are flushed out.  Neither
       [1m.R1 [22mnor [1m.R2 [22mlines, nor anything between them, is output.

       Commands are separated by newlines or semicolons.  A  number  sign  ([1m#[22m)
       introduces  a comment that extends to the end of the line, but does not
       conceal the newline.  Each command is broken up into words.  Words  are
       separated  by spaces or tabs.  A word that begins with a (neutral) dou‐
       ble quote ([1m"[22m) extends to the next double quote that is not followed  by
       another  double  quote.  If there is no such double quote, the word ex‐
       tends to the end of the line.  Pairs of double quotes in a word  begin‐
       ning  with a double quote collapse to one double quote.  Neither a num‐
       ber sign nor a semicolon is recognized inside double  quotes.   A  line
       can  be  continued by ending it with a backslash “[1m\[22m”; this works every‐
       where except after a number sign.

       Each command [4mname[24m that is marked with * has an associated negative com‐
       mand [1mno-[4m[22mname[24m that undoes the effect of [4mname[24m.  For example, the  [1mno-sort[0m
       command  specifies  that references should not be sorted.  The negative
       commands take no arguments.

       In the following description each argument must be a single word; [4mfield[0m
       is used for a single upper or lower case letter naming a field;  [4mfields[0m
       is used for a sequence of such letters; [4mm[24m and [4mn[24m are used for a non‐neg‐
       ative numbers; [4mstring[24m is used for an arbitrary string; [4mfile[24m is used for
       the name of a file.

       [1mabbreviate[22m* [4mfields[24m [4mstring1[24m [4mstring2[24m [4mstring3[24m [4mstring4[0m
              Abbreviate the first names of [4mfields[24m.  An initial letter will be
              separated  from another initial letter by [4mstring1[24m, from the last
              name by [4mstring2[24m, and from anything else (such as “von” or  “de”)
              by  [4mstring3[24m.  These default to a period followed by a space.  In
              a hyphenated first name, the initial of the first  part  of  the
              name will be separated from the hyphen by [4mstring4[24m; this defaults
              to  a period.  No attempt is made to handle any ambiguities that
              might result from abbreviation.  Names  are  abbreviated  before
              sorting and before label construction.

       [1mabbreviate-label-ranges[22m* [4mstring[0m
              Three  or  more adjacent labels that refer to consecutive refer‐
              ences will be abbreviated to a label consisting of the first la‐
              bel, followed by [4mstring[24m, followed by the last  label.   This  is
              mainly useful with numeric labels.  If [4mstring[24m is omitted, it de‐
              faults to “[1m-[22m”.

       [1maccumulate[22m*
              Accumulate  references  instead of writing out each reference as
              it is encountered.  Accumulated references will be  written  out
              whenever a reference of the form
                     [1m.[[0m
                     [1m$LIST$[0m
                     [1m.][0m
              is  encountered,  after all input files have been processed, and
              whenever a [1m.R1 [22mline is recognized.

       [1mannotate[22m* [4mfield[24m [4mstring[0m
              [4mfield[24m is an annotation; print it at the end of the reference  as
              a paragraph preceded by the line

                     [1m.[4m[22mstring[0m

              If  [4mstring[24m  is  omitted, it will default to [1mAP[22m; if [4mfield[24m is also
              omitted it will default to [1mX[22m.  Only one field can be an  annota‐
              tion.

       [1marticles [4m[22mstring[24m ...
              Each  [4mstring[24m  is a definite or indefinite article, and should be
              ignored at the beginning of [1mT [22mfields when  sorting.   Initially,
              “a”, “an”, and “the” are recognized as articles.

       [1mbibliography [4m[22mfile[24m ...
              Write  out  all  the  references contained in each bibliographic
              database [4mfile[24m.  This command should  come  last  in  an  [1m.R1[22m/[1m.R2[0m
              block.

       [1mbracket-label [4m[22mstring1[24m [4mstring2[24m [4mstring3[0m
              In  the  text,  bracket each label with [4mstring1[24m and [4mstring2[24m.  An
              occurrence of [4mstring2[24m immediately followed by  [4mstring1[24m  will  be
              turned into [4mstring3[24m.  The default behavior is as follows.
                     [1mbracket-label \*([. \*(.] ", "[0m

       [1mcapitalize [4m[22mfields[0m
              Convert [4mfields[24m to caps and small caps.

       [1mcompatible[22m*
              Recognize  [1m.R1  [22mand  [1m.R2 [22meven when followed by a character other
              than space or newline.

       [1mdatabase [4m[22mfile[24m ...
              Search each bibliographic database [4mfile[24m.  For each [4mfile[24m,  if  an
              index  file[4m.i[24m  created  by  [4mindxbib[24m(1)  exists,  then it will be
              searched instead; each index can cover multiple databases.

       [1mdate-as-label[22m* [4mstring[0m
              [4mstring[24m is a label expression that specifies a string with  which
              to  replace  the [1mD [22mfield after constructing the label.  See sub‐
              section “Label expressions” below for a description of label ex‐
              pressions.  This command is useful if you do not  want  explicit
              labels  in  the  reference  list, but instead want to handle any
              necessary disambiguation by qualifying the  date  in  some  way.
              The  label  used in the text would typically be some combination
              of the author and date.  In most cases you should also  use  the
              [1mno-label-in-reference [22mcommand.  For example,
                     [1mdate-as-label D.+yD.y%a*D.-y[0m
              would  attach  a disambiguating letter to the year part of the [1mD[0m
              field in the reference.

       [1mdefault-database[22m*
              The default database should be searched.  This  is  the  default
              behavior,  so  the negative version of this command is more use‐
              ful.  [4mrefer[24m determines whether the default  database  should  be
              searched  on  the  first  occasion that it needs to do a search.
              Thus a [1mno-default-database [22mcommand must be given before then, in
              order to be effective.

       [1mdiscard[22m* [4mfields[0m
              When the reference is  read,  [4mfields[24m  should  be  discarded;  no
              string definitions for [4mfields[24m will be output.  Initially, [4mfields[0m
              are [1mXYZ[22m.

       [1met-al[22m* [4mstring[24m [4mm[24m [4mn[0m
              Control  use of [1met al. [22min the evaluation of [1m@ [22mexpressions in la‐
              bel expressions.  If the number of authors needed  to  make  the
              author sequence unambiguous is [4mu[24m and the total number of authors
              is  [4mt[24m  then the last [4mt[24m-[4mu[24m authors will be replaced by [4mstring[24m pro‐
              vided that [4mt[24m-[4mu[24m is not less than [4mm[24m and [4mt[24m is not less than [4mn[24m.  The
              default behavior is as follows.
                     [1met-al " et al" 2 3[0m
              Note the absence of a dot from  the  end  of  the  abbreviation,
              which is arguably not correct.  ([4mEt[24m [4mal[24m[.]  is short for [4met[24m [4malli[24m,
              as [4metc.[24m is short for [4met[24m [4mcetera[24m.)

       [1minclude [4m[22mfile[0m
              Include [4mfile[24m and interpret the contents as commands.

       [1mjoin-authors [4m[22mstring1[24m [4mstring2[24m [4mstring3[0m
              Join multiple authors together with [4mstring[24ms.  When there are ex‐
              actly two authors, they will be joined with [4mstring1[24m.  When there
              are  more  than two authors, all but the last two will be joined
              with [4mstring2[24m, and the last  two  authors  will  be  joined  with
              [4mstring3[24m.   If [4mstring3[24m is omitted, it will default to [4mstring1[24m; if
              [4mstring2[24m is also omitted it will also default  to  [4mstring1[24m.   For
              example,
                     join-authors " and " ", " ", and "
              will restore the default method for joining authors.

       [1mlabel-in-reference[22m*
              When  outputting  the  reference, define the string [1m[F [22mto be the
              reference’s label.  This is the default behavior, so  the  nega‐
              tive version of this command is more useful.

       [1mlabel-in-text[22m*
              For  each  reference output a label in the text.  The label will
              be separated from the  surrounding  text  as  described  in  the
              [1mbracket-label  [22mcommand.   This  is  the default behavior, so the
              negative version of this command is more useful.

       [1mlabel [4m[22mstring[0m
              [4mstring[24m is a label expression describing how to label each refer‐
              ence.

       [1mseparate-label-second-parts [4m[22mstring[0m
              When merging two‐part labels, separate the second  part  of  the
              second label from the first label with [4mstring[24m.  See the descrip‐
              tion of the [1m<> [22mlabel expression.

       [1mmove-punctuation[22m*
              In  the  text,  move any punctuation at the end of line past the
              label.  It is usually a good idea to give  this  command  unless
              you are using superscripted numbers as labels.

       [1mreverse[22m* [4mstring[0m
              Reverse  the  fields whose names are in [4mstring[24m.  Each field name
              can be followed by a number which  says  how  many  such  fields
              should be reversed.  If no number is given for a field, all such
              fields will be reversed.

       [1msearch-ignore[22m* [4mfields[0m
              While searching for keys in databases for which no index exists,
              ignore  the  contents  of [4mfields[24m.  Initially, fields [1mXYZ [22mare ig‐
              nored.

       [1msearch-truncate[22m* [4mn[0m
              Only require the first [4mn[24m characters of keys to be given.  In ef‐
              fect when searching for a given key words in  the  database  are
              truncated  to  the maximum of [4mn[24m and the length of the key.  Ini‐
              tially, [4mn[24m is 6.

       [1mshort-label[22m* [4mstring[0m
              [4mstring[24m is a label expression that specifies an alternative (usu‐
              ally shorter) style of label.  This is used when the [1m#  [22mflag  is
              given in the citation.  When using author‐date style labels, the
              identity  of  the  author or authors is sometimes clear from the
              context, and so it may be desirable to omit the  author  or  au‐
              thors from the label.  The [1mshort-label [22mcommand will typically be
              used  to  specify  a label containing just a date and possibly a
              disambiguating letter.

       [1msort[22m* [4mstring[0m
              Sort references according to [4mstring[24m.  References will  automati‐
              cally  be  accumulated.  [4mstring[24m should be a list of field names,
              each followed by a number, indicating how many fields  with  the
              name  should  be  used for sorting.  “[1m+[22m” can be used to indicate
              that all the fields with the name should be used.  Also [1m. [22mcan be
              used to indicate the references should be sorted using the (ten‐
              tative) label.  (Subsection “Label expressions” below  describes
              the concept of a tentative label.)

       [1msort-adjacent-labels[22m*
              Sort labels that are adjacent in the text according to their po‐
              sition  in  the  reference list.  This command should usually be
              given if the [1mabbreviate-label-ranges [22mcommand has been given,  or
              if  the  label  expression  contains a [1m<> [22mexpression.  This will
              have no effect unless references are being accumulated.

   [1mLabel expressions[0m
       Label expressions can be evaluated both normally and tentatively.   The
       result  of  normal evaluation is used for output.  The result of tenta‐
       tive evaluation, called the [4mtentative[24m [4mlabel[24m, is used to gather the  in‐
       formation  that normal evaluation needs to disambiguate the label.  La‐
       bel expressions specified by the [1mdate-as-label [22mand [1mshort-label [22mcommands
       are not evaluated tentatively.  Normal and tentative evaluation are the
       same for all types of expression other than [1m@[22m, [1m*[22m,  and  [1m%  [22mexpressions.
       The description below applies to normal evaluation, except where other‐
       wise specified.

       [4mfield[0m
       [4mfield[24m [4mn[0m
              The [4mn[24m‐th part of [4mfield[24m.  If [4mn[24m is omitted, it defaults to 1.

       [1m'[4m[22mstring[24m[1m'[0m
              The characters in [4mstring[24m literally.

       [1m@      [22mAll the authors joined as specified by the [1mjoin-authors [22mcommand.
              The  whole  of each author’s name will be used.  However, if the
              references are sorted by author (that is, the sort specification
              starts with “[1mA+[22m”), then authors’ last names  will  be  used  in‐
              stead, provided that this does not introduce ambiguity, and also
              an initial subsequence of the authors may be used instead of all
              the authors, again provided that this does not introduce ambigu‐
              ity.   The use of only the last name for the [4mi[24m‐th author of some
              reference is considered to be ambiguous if there is  some  other
              reference, such that the first [4mi[24m-1 authors of the references are
              the  same,  the  [4mi[24m‐th authors are not the same, but the [4mi[24m‐th au‐
              thors last names are the same.  A proper initial subsequence  of
              the  sequence  of authors for some reference is considered to be
              ambiguous if there is a reference with some  other  sequence  of
              authors which also has that subsequence as a proper initial sub‐
              sequence.   When  an initial subsequence of authors is used, the
              remaining authors are replaced by the string  specified  by  the
              [1met-al [22mcommand; this command may also specify additional require‐
              ments  that  must  be  met  before an initial subsequence can be
              used.  [1m@ [22mtentatively evaluates to a canonical representation  of
              the  authors, such that authors that compare equally for sorting
              purpose will have the same representation.

       [1m%[4m[22mn[0m
       [1m%a[0m
       [1m%A[0m
       [1m%i[0m
       [1m%I     [22mThe serial number of the reference formatted  according  to  the
              character  following  the  [1m%[22m.   The serial number of a reference
              is 1 plus the number of earlier references with  same  tentative
              label as this reference.  These expressions tentatively evaluate
              to an empty string.

       [4mexpr[24m[1m*  [22mIf  there  is another reference with the same tentative label as
              this reference, then [4mexpr[24m, otherwise an empty string.  It tenta‐
              tively evaluates to an empty string.

       [4mexpr[24m[1m+[4m[22mn[0m
       [4mexpr[24m[1m-[4m[22mn[24m The first ([1m+[22m) or last ([1m-[22m) [4mn[24m upper or lower case letters or  dig‐
              its  of [4mexpr[24m.  [4mroff[24m special characters (such as [1m\('a[22m) count as a
              single letter.  Accent strings are retained but do not count to‐
              wards the total.

       [4mexpr[24m[1m.l [4m[22mexpr[24m converted to lowercase.

       [4mexpr[24m[1m.u [4m[22mexpr[24m converted to uppercase.

       [4mexpr[24m[1m.c [4m[22mexpr[24m converted to caps and small caps.

       [4mexpr[24m[1m.r [4m[22mexpr[24m reversed so that the last name is first.

       [4mexpr[24m[1m.a [4m[22mexpr[24m with first names  abbreviated.   Fields  specified  in  the
              [1mabbreviate  [22mcommand are abbreviated before any labels are evalu‐
              ated.  Thus [1m.a [22mis useful only when you want a field to be abbre‐
              viated in a label but not in a reference.

       [4mexpr[24m[1m.y [22mThe year part of [4mexpr[24m.

       [4mexpr[24m[1m.+y[0m
              The part of [4mexpr[24m before the year, or the whole  of  [4mexpr[24m  if  it
              does not contain a year.

       [4mexpr[24m[1m.-y[0m
              The part of [4mexpr[24m after the year, or an empty string if [4mexpr[24m does
              not contain a year.

       [4mexpr[24m[1m.n [22mThe last name part of [4mexpr[24m.

       [4mexpr1[24m[1m~[4m[22mexpr2[0m
              [4mexpr1[24m  except  that  if the last character of [4mexpr1[24m is [1m- [22mthen it
              will be replaced by [4mexpr2[24m.

       [4mexpr1[24m [4mexpr2[0m
              The concatenation of [4mexpr1[24m and [4mexpr2[24m.

       [4mexpr1[24m[1m|[4m[22mexpr2[0m
              If [4mexpr1[24m is non‐empty then [4mexpr1[24m otherwise [4mexpr2[24m.

       [4mexpr1[24m[1m&[4m[22mexpr2[0m
              If [4mexpr1[24m is non‐empty then [4mexpr2[24m otherwise an empty string.

       [4mexpr1[24m[1m?[4m[22mexpr2[24m[1m:[4m[22mexpr3[0m
              If [4mexpr1[24m is non‐empty then [4mexpr2[24m otherwise [4mexpr3[24m.

       [1m<[4m[22mexpr[24m[1m> [22mThe label is in two parts, which are separated by [4mexpr[24m.  Two ad‐
              jacent two‐part labels which have the same first  part  will  be
              merged by appending the second part of the second label onto the
              first   label   separated   by   the  string  specified  in  the
              [1mseparate-label-second-parts [22mcommand (initially, a comma followed
              by a space); the resulting label will also be a  two‐part  label
              with  the  same  first part as before merging, and so additional
              labels can be merged into it.  It is permissible for  the  first
              part  to be empty; this may be desirable for expressions used in
              the [1mshort-label [22mcommand.

       [1m([4m[22mexpr[24m[1m) [22mThe same as [4mexpr[24m.  Used for grouping.

       The above expressions  are  listed  in  order  of  precedence  (highest
       first); [1m& [22mand [1m| [22mhave the same precedence.

   [1mMacro interface[0m
       Each  reference starts with a call to the macro [1m]-[22m.  The string [1m[F [22mwill
       be  defined  to  be  the  label  for   this   reference,   unless   the
       [1mno-label-in-reference [22mcommand has been given.  There then follows a se‐
       ries  of  string definitions, one for each field: string [1m[[4m[22mX[24m corresponds
       to field [4mX[24m.  The register [1m[P [22mis set to 1 if  the  [1mP  [22mfield  contains  a
       range  of pages.  The [1m[T[22m, [1m[A [22mand [1m[O [22mregisters are set to 1 according as
       the [1mT[22m, [1mA [22mand [1mO [22mfields end with any of [1m.?! [22m(an  end‐of‐sentence  charac‐
       ter).   The [1m[E [22mregister will be set to 1 if the [1m[E [22mstring contains more
       than one name.  The reference is followed by a call to  the  [1m][  [22mmacro.
       The  first  argument to this macro gives a number representing the type
       of the reference.  If a reference contains a [1mJ [22mfield, it will be  clas‐
       sified  as  type  1,  otherwise  if  it  contains a [1mB [22mfield, it will be
       type 3, otherwise if it contains a [1mG [22mor [1mR [22mfield it will be type 4, oth‐
       erwise if it contains an [1mI [22mfield it will be type 2, otherwise  it  will
       be type 0.  The second argument is a symbolic name for the type: [1mother[22m,
       [1mjournal-article[22m, [1mbook[22m, [1marticle-in-book[22m, or [1mtech-report[22m.  Groups of ref‐
       erences  that have been accumulated or are produced by the [1mbibliography[0m
       command are preceded by a call to the [1m]< [22mmacro and followed by  a  call
       to the [1m]> [22mmacro.

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-R     [22mDon’t recognize lines beginning with [1m.R1[22m/[1m.R2[22m.

       Other options are equivalent to [4mrefer[24m commands.

       [1m-a [4m[22mn[24m            [1mreverse A[4m[22mn[0m

       [1m-b              no-label-in-text; no-label-in-reference[0m

       [1m-B              [22mSee below.

       [1m-c [4m[22mfields[24m       [1mcapitalize [4m[22mfields[0m

       [1m-C              compatible[0m

       [1m-e              accumulate[0m

       [1m-f [4m[22mn[24m            [1mlabel %[4m[22mn[0m

       [1m-i [4m[22mfields[24m       [1msearch-ignore [4m[22mfields[0m

       [1m-k              label L~%a[0m

       [1m-k [4m[22mfield[24m        [1mlabel [4m[22mfield[24m[1m~%a[0m

       [1m-l              label A.nD.y%a[0m

       [1m-l [4m[22mm[24m            [1mlabel A.n+[4m[22mm[24m[1mD.y%a[0m

       [1m-l ,[4m[22mn[24m           [1mlabel A.nD.y-[4m[22mn[24m[1m%a[0m

       [1m-l [4m[22mm[24m[1m,[4m[22mn[24m          [1mlabel A.n+[4m[22mm[24m[1mD.y-[4m[22mn[24m[1m%a[0m

       [1m-n              no-default-database[0m

       [1m-p [4m[22mdb‐file[24m      [1mdatabase [4m[22mdb‐file[0m

       [1m-P              move-punctuation[0m

       [1m-s [4m[22mspec[24m         [1msort [4m[22mspec[0m

       [1m-S              label "(A.n|Q) ', ' (D.y|D)"; bracket‐label " (" ) "; "[0m

       [1m-t [4m[22mn[24m            [1msearch-truncate [4m[22mn[0m

       The [1mB [22moption has command equivalents with the addition  that  the  file
       names specified on the command line are processed as if they were argu‐
       ments to the [1mbibliography [22mcommand instead of in the normal way.

       [1m-B              annotate X AP; no-label-in-reference[0m

       [1m-B [4m[22mfield[24m[1m.[4m[22mmacro[24m  [1mannotate [4m[22mfield[24m [4mmacro[24m[1m; no-label-in-reference[0m

[1mEnvironment[0m
       [4mREFER[24m  If set, overrides the default database.

[1mFiles[0m
       [4m/usr/dict/papers/Ind[0m
              Default database.

       file[4m.i[24m Index files.

       [4m/usr/share/groff/1.23.0/tmac/refer.tmac[0m
              defines  macros  and strings facilitating integration with macro
              packages that wish to support [4mrefer[24m.

       [4mrefer[24m uses temporary files.  See the [4mgroff[24m(1) man page for  details  of
       where such files are created.

[1mBugs[0m
       In  label  expressions, [1m<> [22mexpressions are ignored inside [1m.[4m[22mchar[24m expres‐
       sions.

[1mExamples[0m
       We can illustrate the operation of [4mrefer[24m with  a  sample  bibliographic
       database  containing  one entry and a simple [4mroff[24m document to cite that
       entry.

              $ [1mcat > my-db-file[0m
              [1m%A Daniel P.\& Friedman[0m
              [1m%A Matthias Felleisen[0m
              [1m%C Cambridge, Massachusetts[0m
              [1m%D 1996[0m
              [1m%I The MIT Press[0m
              [1m%T The Little Schemer, Fourth Edition[0m
              $ [1mrefer ‐p my-db-file[0m
              [1mRead the book[0m
              [1m.[[0m
              [1mfriedman[0m
              [1m.][0m
              [1mon your summer vacation.[0m
              [4m<Control+D>[0m
              .lf 1 -
              Read the book\*([.1\*(.]
              .ds [F 1
              .]-
              .ds [A Daniel P. Friedman and Matthias Felleisen
              .ds [C Cambridge, Massachusetts
              .ds [D 1996
              .ds [I The MIT Press
              .ds [T The Little Schemer, Fourth Edition
              .nr [T 0
              .nr [A 0
              .][ 2 book
              .lf 5 -
              on your summer vacation.

       The foregoing shows us that [4mrefer[24m (a) produces a label “1”; (b)  brack‐
       ets  that label with interpolations of the “[1m[.[22m”  and “[1m.][22m”  strings; (c)
       calls a macro “[1m]-[22m”; (d) defines strings and  registers  containing  the
       label and bibliographic data for the reference; (e) calls a macro “[1m][[22m”;
       and (f) uses the [1mlf [22mrequest to restore the line numbers of the original
       input.  As discussed in subsection “Macro interface” above, it is up to
       the  document  or a macro package to employ and format this information
       usefully.  Let us see how we might turn [4mgroff_ms[24m(7) to this task.

              $ [1mREFER=my-db-file groff -R -ms[0m
              [1m.LP[0m
              [1mRead the book[0m
              [1m.[[0m
              [1mfriedman[0m
              [1m.][0m
              [1mon your summer vacation.[0m
              [1mCommentary is available.\*{*\*}[0m
              [1m.FS \*{*\*}[0m
              [1mSpace reserved for penetrating insight.[0m
              [1m.FE[0m

       [4mms[24m’s automatic footnote numbering mechanism is not aware of [4mrefer[24m’s la‐
       bel numbering, so we have manually specified a (superscripted) symbolic
       footnote for our non‐bibliographic aside.

[1mSee also[0m
       “Some Applications of Inverted Indexes on the Unix System”,  by  M.  E.
       Lesk,  1978,  AT&T Bell Laboratories Computing Science Technical Report
       No. 69.

       [4mindxbib[24m(1), [4mlookbib[24m(1), [4mlkbib[24m(1)

groff 1.23.0                      5 July 2023                         [4mrefer[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4msoelim[24m(1)                   General Commands Manual                  [4msoelim[24m(1)

[1mName[0m
       soelim - recursively interpolate source requests in [4mroff[24m or other  text
       files

[1mSynopsis[0m
       [1msoelim [22m[[1m-Crt[22m] [[1m-I [4m[22mdir[24m] [[4minput‐file[24m ...]

       [1msoelim --help[0m

       [1msoelim -v[0m
       [1msoelim --version[0m

[1mDescription[0m
       GNU  [4msoelim[24m is a preprocessor for the [4mgroff[24m(7) document formatting sys‐
       tem.  [4msoelim[24m works as a filter to eliminate source requests in  [4mroff[24m(7)
       input files; that is, it replaces lines of the form “[1m.so [4m[22mincluded‐file[24m”
       within  each text [4minput‐file[24m with the contents of [4mincluded‐file[24m, recur‐
       sively.  By default, it writes [1mlf [22mrequests as well to record  the  name
       and line number of each [4minput‐file[24m and [4mincluded‐file[24m, so that any diag‐
       nostics  produced  by  later processing can be accurately traced to the
       original input.  Options allow this information to be  suppressed  ([1m-r[22m)
       or supplied in TeX comments instead ([1m-t[22m).  In the absence of [4minput‐file[0m
       arguments,  [4msoelim[24m  reads the standard input stream.  Output is written
       to the standard output stream.

       If the name of a [4mmacro‐file[24m contains a backslash, use [1m\\ [22mor [1m\e [22mto embed
       it.  To embed a space, write “[1m\ [22m” (backslash followed by a space).  Any
       other escape sequence in [4mmacro‐file[24m, including “[1m\[rs][22m”, prevents [4msoelim[0m
       from replacing the source request.

       The dot must be at the beginning of a line and must be followed by “[1mso[22m”
       without intervening spaces or tabs for [4msoelim[24m to handle it.  This  con‐
       vention  allows  source  requests  to be “protected” from processing by
       [4msoelim[24m, for instance as part of macro definitions or “[1mif[22m” requests.

       There must also be at least one space between “[1mso[22m” and  its  [4mmacro‐file[0m
       argument.  The [1m-C [22moption overrides this requirement.

       The  foregoing  is the limit of [4msoelim[24m’s understanding of the [4mroff[24m lan‐
       guage; it does not, for example, replace the input line
              .if 1 .so otherfile
       with the contents of [4motherfile[24m.  With its [1m-r [22moption, therefore,  [4msoelim[0m
       can  be used to process text files in general, to flatten a tree of in‐
       put documents.

       [4msoelim[24m was designed to handle situations where the  target  of  a  [4mroff[0m
       source   request  requires  a  preprocessor  such  as  [4meqn[24m(1),  [4mpic[24m(1),
       [4mrefer[24m(1), or [4mtbl[24m(1).  The usual processing sequence of [4mgroff[24m(1)  is  as
       follows.

                 input        sourced
                 file          file
                   ⎪             ⎪
                   ↓             ↓
               preprocessor ⎯→ troff ⎯→ postprocessor
                                             ⎪
                                             ↓
                                          output
                                           file

       That  is, files sourced with “[1mso[22m” are normally read [4monly[24m by the format‐
       ter, [4mtroff[24m.  [4msoelim[24m is [4mnot[24m required for [4mtroff[24m to source files.

       If a file to be sourced should also be preprocessed, it must already be
       read [4mbefore[24m the input file passes through  the  preprocessor.   [4msoelim[24m,
       normally invoked via [4mgroff[24m’s [1m-s [22moption, handles this.

                 input
                 file
                   ⎪
                   ↓
                 soelim ⎯→ preprocessor ⎯→ troff ⎯→ postprocessor
                   ↑                                     ⎪
                   ⎪                                     ↓
                sourced                               output
                 file                                  file

[1mOptions[0m
       [1m--help  [22mdisplays  a  usage message, while [1m-v [22mand [1m--version [22mshow version
       information; all exit afterward.

       [1m-C     [22mRecognize an input line starting with [1m.so [22meven  if  a  character
              other than a space or newline follows.

       [1m-I [4m[22mdir[24m Search the directory [4mdir[24m path for [4minput‐[24m and [4mincluded‐files.[24m  [1m-I[0m
              may  be  specified  more  than once; each [4mdir[24m is searched in the
              given order.  To search the  current  working  directory  before
              others,  add  “[1m-I  .[22m”  at  the  desired  place;  it is otherwise
              searched last.

       [1m-r     [22mWrite files “raw”; do not add [1mlf [22mrequests.

       [1m-t     [22mEmit TeX comment lines starting with “[1m%[22m” indicating the  current
              file  and line number, rather than [1mlf [22mrequests for the same pur‐
              pose.

       If both [1m-r [22mand [1m-t [22mare given, the last one specified controls.

[1mSee also[0m
       [4mgroff[24m(1)

groff 1.23.0                      5 July 2023                        [4msoelim[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mtbl[24m(1)                      General Commands Manual                     [4mtbl[24m(1)

[1mName[0m
       tbl - prepare tables for [4mgroff[24m documents

[1mSynopsis[0m
       [1mtbl [22m[[1m-C[22m] [[4mfile[24m ...]

       [1mtbl --help[0m

       [1mtbl -v[0m
       [1mtbl --version[0m

[1mDescription[0m
       The GNU implementation of [4mtbl[24m is part of the [4mgroff[24m(1) document  format‐
       ting  system.   [4mtbl[24m is a [4mtroff[24m(1) preprocessor that translates descrip‐
       tions of tables embedded in [4mroff[24m(7) input files into the  language  un‐
       derstood by [4mtroff[24m.  It copies the contents of each [4mfile[24m to the standard
       output stream, except that lines between [1m.TS [22mand [1m.TE [22mare interpreted as
       table  descriptions.  While GNU [4mtbl[24m’s input syntax is highly compatible
       with AT&T [4mtbl[24m, the output GNU [4mtbl[24m produces cannot be processed by  AT&T
       [4mtroff[24m;  GNU [4mtroff[24m (or a [4mtroff[24m implementing any GNU extensions employed)
       must be used.  Normally, [4mtbl[24m is not executed directly by the user,  but
       invoked  by  specifying the [1m-t [22moption to [4mgroff[24m(1).  If no [4mfile[24m operands
       are given on the command line, or if [4mfile[24m is “[1m-[22m”, [4mtbl[24m reads  the  stan‐
       dard input stream.

   [1mOverview[0m
       [4mtbl[24m  expects  to find table descriptions between input lines that begin
       with [1m.TS [22m(table start) and [1m.TE [22m(table end).  Each such [4mtable[24m [4mregion[24m en‐
       closes one or more table descriptions.  Within a  table  region,  table
       descriptions  beyond  the  first must each be preceded by an input line
       beginning with [1m.T&[22m.  This mechanism does not start a new table  region;
       all  table descriptions are treated as part of their [1m.TS[22m/[1m.TE [22menclosure,
       even if they are boxed or have column headings that  repeat  on  subse‐
       quent pages (see below).

       (Experienced  [4mroff[24m users should observe that [4mtbl[24m is not a [4mroff[24m language
       interpreter: the default control character must be used, and no  spaces
       or tabs are permitted between the control character and the macro name.
       These  [4mtbl[24m  input  tokens remain as‐is in the output, where they become
       ordinary macro calls.  Macro packages  often  define  [1mTS[22m,  [1mT&[22m,  and  [1mTE[0m
       macros  to  handle issues of table placement on the page.  [4mtbl[24m produces
       [4mgroff[24m code to define these macros as empty if their definitions do  not
       exist when the formatter encounters a table region.)

       Each  table  region may begin with [4mregion[24m [4moptions,[24m and must contain one
       or more [4mtable[24m [4mdefinitions;[24m each  table  definition  contains  a  [4mformat[0m
       [4mspecification[24m  followed  by  one or more input lines (rows) of [4mentries.[0m
       These entries comprise the [4mtable[24m [4mdata.[0m

   [1mRegion options[0m
       The line immediately following the [1m.TS [22mtoken  may  specify  region  op‐
       tions,  keywords  that influence the interpretation or rendering of the
       region as a whole or all  table  entries  within  it  indiscriminately.
       They  must be separated by commas, spaces, or tabs.  Those that require
       a parenthesized argument permit spaces and tabs  between  the  option’s
       name and the opening parenthesis.  Options accumulate and cannot be un‐
       set  within a region once declared; if an option that takes a parameter
       is repeated, the last occurrence controls.  If present, the set of  re‐
       gion options must be terminated with a semicolon ([1m;[22m).

       Any  of  the  [1mallbox[22m, [1mbox[22m, [1mdoublebox[22m, [1mframe[22m, and [1mdoubleframe [22mregion op‐
       tions makes a table “boxed” for the purpose of later discussion.

       [1mallbox [22mEnclose each table entry in a box; implies [1mbox[22m.

       [1mbox    [22mEnclose the entire table region in a box.  As a  GNU  extension,
              the alternative option name [1mframe [22mis also recognized.

       [1mcenter [22mCenter  the table region with respect to the current indentation
              and line length; the default is to left‐align it.  As a GNU  ex‐
              tension, the alternative option name [1mcentre [22mis also recognized.

       [1mdecimalpoint([4m[22mc[24m[1m)[0m
              Recognize  character [4mc[24m as the decimal separator in columns using
              the [1mN [22m(numeric) classifier (see subsection “Column  classifiers”
              below).  This is a GNU extension.

       [1mdelim([4m[22mxy[24m[1m)[0m
              Recognize  characters  [4mx[24m  and [4my[24m as start and end delimiters, re‐
              spectively, for [4meqn[24m(1) input, and ignore input between them.   [4mx[0m
              and [4my[24m need not be distinct.

       [1mdoublebox[0m
              Enclose  the  entire  table region in a double box; implies [1mbox[22m.
              As a GNU extension, the alternative option name  [1mdoubleframe  [22mis
              also recognized.

       [1mexpand [22mSpread  the table horizontally to fill the available space (line
              length minus indentation) by increasing column separation.   Or‐
              dinarily,  a table is made only as wide as necessary to accommo‐
              date the widths  of  its  entries  and  its  column  separations
              (whether  specified or default).  When [1mexpand [22mapplies to a table
              that exceeds the available horizontal space,  column  separation
              is  reduced  as  far  as necessary (even to zero).  [4mtbl[24m produces
              [4mgroff[24m input that issues a diagnostic if such compression occurs.
              The column modifier [1mx [22m(see below) overrides this option.

       [1mlinesize([4m[22mn[24m[1m)[0m
              Draw lines or  rules  (e.g.,  from  [1mbox[22m)  with  a  thickness  of
              [4mn[24m  points.  The default is the current type size when the region
              begins.  This option is ignored on terminal devices.

       [1mnokeep [22mDon’t use [4mroff[24m diversions to manage page breaks.  Normally,  [4mtbl[0m
              employs  them to avoid breaking a page within a table row.  This
              usage can sometimes interact badly with macro packages’ own  use
              of  diversions—when  footnotes, for example, are employed.  This
              is a GNU extension.

       [1mnospaces[0m
              Ignore leading and trailing spaces in table entries.  This is  a
              GNU extension.

       [1mnowarn [22mSuppress  diagnostic  messages  produced  at document formatting
              time when the line or page lengths are inadequate to  contain  a
              table row.  This is a GNU extension.

       [1mtab([4m[22mc[24m[1m) [22mUse  the  character  [4mc[24m instead of a tab to separate entries in a
              row of table data.

   [1mTable format specification[0m
       The table format specification is mandatory: it determines  the  number
       of columns in the table and directs how the entries within it are to be
       typeset.   The  format specification is a series of column [4mdescriptors.[0m
       Each descriptor encodes a [4mclassifier[24m followed by  zero  or  more  [4mmodi‐[0m
       [4mfiers.[24m   Classifiers  are  letters  (recognized  case‐insensitively) or
       punctuation symbols; modifiers consist of or begin with letters or  nu‐
       merals.  Spaces, tabs, newlines, and commas separate descriptors.  New‐
       lines and commas are special; they apply the descriptors following them
       to  a subsequent row of the table.  (This enables column headings to be
       centered or emboldened while the table entries for the  data  are  not,
       for instance.)  We term the resulting group of column descriptors a [4mrow[0m
       [4mdefinition.[24m   Within  a  row  definition, separation between column de‐
       scriptors (by spaces or tabs) is often optional; only  some  modifiers,
       described below, make separation necessary.

       Each  column descriptor begins with a mandatory [4mclassifier,[24m a character
       that selects from one of several arrangements.  Some determine the  po‐
       sitioning  of  table entries within a rectangular cell: centered, left‐
       aligned, numeric (aligned to a configurable decimal separator), and  so
       on.   Others  perform special operations like drawing lines or spanning
       entries from adjacent cells in the table.  Except for “[1m|[22m”, any  classi‐
       fier  can be followed by one or more [4mmodifiers;[24m some of these accept an
       argument, which in GNU [4mtbl[24m  can  be  parenthesized.   Modifiers  select
       fonts, set the type size, and perform other tasks described below.

       The format specification can occupy multiple input lines, but must con‐
       clude with a dot “[1m.[22m” followed by a newline.  Each row definition is ap‐
       plied  in turn to one row of the table.  The last row definition is ap‐
       plied to rows of table data in excess of the row definitions.

       For clarity in this document’s examples, we shall write classifiers  in
       uppercase  and  modifiers  in  lowercase.  Thus, “[1mCbCb,LR.[22m” defines two
       rows of two columns.  The first row’s entries are  centered  and  bold‐
       faced;  the  second  and any further rows’ first and second columns are
       left‐ and right‐aligned, respectively.

       The row definition with the most column descriptors determines the num‐
       ber of columns in the table; any row definition with fewer  is  implic‐
       itly  extended  on the right‐hand side with [1mL [22mclassifiers as many times
       as necessary to make the table rectangular.

   [1mColumn classifiers[0m
       The [1mL[22m, [1mR[22m, and [1mC [22mclassifiers are the easiest to understand and use.

       [1mA[22m, [1ma   [22mCenter longest entry in this column,  left‐align  remaining  en‐
              tries in the column with respect to the centered entry, then in‐
              dent  all  entries  by one en.  Such “alphabetic” entries (hence
              the name of the classifier) can be used in the same column as [1mL[22m‐
              classified entries, as in “[1mLL,AR.[22m”.  The  [1mA  [22mentries  are  often
              termed “sub‐columns” due to their indentation.

       [1mC[22m, [1mc   [22mCenter entry within the column.

       [1mL[22m, [1ml   [22mLeft‐align entry within the column.

       [1mN[22m, [1mn   [22mNumerically  align  entry  in the column.  [4mtbl[24m aligns columns of
              numbers vertically at the units place.  If multiple decimal sep‐
              arators are adjacent to a digit, it uses the rightmost  one  for
              vertical  alignment.   If  there  is  no  decimal separator, the
              rightmost digit is used for vertical alignment;  otherwise,  [4mtbl[0m
              centers  the  entry within the column.  The [4mroff[24m dummy character
              [1m\& [22min an entry marks the glyph preceding  it  (if  any)  as  the
              units  place; if multiple instances occur in the data, the left‐
              most is used for alignment.

              If [1mN[22m‐classified entries share a column with [1mL [22mor [1mR [22mentries,  [4mtbl[0m
              centers the widest [1mN [22mentry with respect to the widest [1mL [22mor [1mR [22men‐
              try,  preserving the alignment of [1mN [22mentries with respect to each
              other.

              The appearance of [4meqn[24m equations within [1mN[22m‐classified columns  can
              be  troublesome  due to the foregoing textual scan for a decimal
              separator.  Use the [1mdelim [22mregion option to make [4mtbl[24m  ignore  the
              data within [4meqn[24m delimiters for that purpose.

       [1mR[22m, [1mr   [22mRight‐align entry within the column.

       [1mS[22m, [1ms   [22mSpan previous entry on the left into this column.

       [1m^      [22mSpan  entry  in  the same column from the previous row into this
              row.

       [1m_[22m, [1m-   [22mReplace table entry with a horizontal rule.  An empty table  en‐
              try  is  expected  to correspond to this classifier; if data are
              found there, [4mtbl[24m issues a diagnostic message.

       [1m=      [22mReplace table entry with a double horizontal rule.  An empty ta‐
              ble entry is expected to correspond to this classifier; if  data
              are found there, [4mtbl[24m issues a diagnostic message.

       [1m|      [22mPlace a vertical rule (line) on the corresponding row of the ta‐
              ble  (if  two  of  these  are adjacent, a double vertical rule).
              This classifier does not contribute to the column count  and  no
              table  entries  correspond  to it.  A [1m| [22mto the left of the first
              column descriptor or to the right of the  last  one  produces  a
              vertical rule at the edge of the table; these are redundant (and
              ignored) in boxed tables.

       To  change  the  table format within a [4mtbl[24m region, use the [1m.T& [22mtoken at
       the start of a line.  It is followed by a format specification and  ta‐
       ble data, but [4mnot[24m region options.  The quantity of columns in a new ta‐
       ble format thus introduced cannot increase relative to the previous ta‐
       ble  format;  in that case, you must end the table region and start an‐
       other.  If that will not serve because the region uses box  options  or
       the columns align in an undesirable manner, you must design the initial
       table  format  specification to include the maximum quantity of columns
       required, and use the [1mS [22mhorizontal spanning classifier where  necessary
       to achieve the desired columnar alignment.

       Attempting  to horizontally span in the first column or vertically span
       on the first row is an error.  Non‐rectangular span areas are also  not
       supported.

   [1mColumn modifiers[0m
       Any  number  of modifiers can follow a column classifier.  Arguments to
       modifiers, where accepted, are case‐sensitive.  If the same modifier is
       applied to a column specifier more than once, or if  conflicting  modi‐
       fiers are applied, only the last occurrence has effect.  The modifier [1mx[0m
       is  mutually  exclusive  with  [1me [22mand [1mw[22m, but [1me [22mis not mutually exclusive
       with [1mw[22m; if these are used in combination, [1mx [22munsets both [1me [22mand [1mw[22m,  while
       either [1me [22mor [1mw [22moverrides [1mx[22m.

       [1mb[22m, [1mB   [22mTypeset entry in boldface, abbreviating [1mf(B)[22m.

       [1md[22m, [1mD   [22mAlign  a  vertically spanned table entry to the bottom (“down”),
              instead of the center, of its range.  This is a GNU extension.

       [1me[22m, [1mE   [22mEqualize the widths of columns with this modifier.   The  column
              with the largest width controls.  This modifier sets the default
              line length used in a text block.

       [1mf[22m, [1mF   [22mSelect  the typeface for the table entry.  This modifier must be
              followed by a font or style name  (one  or  two  characters  not
              starting with a digit), font mounting position (a single digit),
              or  a  name  or  mounting position of any length in parentheses.
              The last form is a GNU extension.  (The parameter corresponds to
              that accepted by the [4mtroff[24m [1mft [22mrequest.)  A  one‐character  argu‐
              ment  not in parentheses must be separated by one or more spaces
              or tabs from what follows.

       [1mi[22m, [1mI   [22mTypeset entry in an oblique or italic face, abbreviating [1mf(I)[22m.

       [1mm[22m, [1mM   [22mCall a [4mgroff[24m macro before typesetting a text block (see  subsec‐
              tion “Text blocks” below).  This is a GNU extension.  This modi‐
              fier  must  be followed by a macro name of one or two characters
              or a name of any length in parentheses.  A  one‐character  macro
              name  not in parentheses must be separated by one or more spaces
              or tabs from what follows.  The named macro must be defined  be‐
              fore the table region containing this column modifier is encoun‐
              tered.   The  macro should contain only simple [4mgroff[24m requests to
              change text formatting, like  adjustment  or  hyphenation.   The
              macro  is  called  [4mafter[24m  the column modifiers [1mb[22m, [1mf[22m, [1mi[22m, [1mp[22m, and [1mv[0m
              take effect; it can thus override other column modifiers.

       [1mp[22m, [1mP   [22mSet the type size for the table entry.  This  modifier  must  be
              followed  by an integer [4mn[24m with an optional leading sign.  If un‐
              signed, the type size is set to [4mn[24m scaled points.  Otherwise, the
              type size is incremented or decremented per the sign by [4mn[24m scaled
              points.  The use of a signed multi‐digit number is a GNU  exten‐
              sion.   (The parameter corresponds to that accepted by the [4mtroff[0m
              [1mps [22mrequest.)  If a type size modifier is followed  by  a  column
              separation  modifier  (see  below), they must be separated by at
              least one space or tab.

       [1mt[22m, [1mT   [22mAlign a vertically spanned table entry to the  top,  instead  of
              the center, of its range.

       [1mu[22m, [1mU   [22mMove  the  column up one half‐line, “staggering” the rows.  This
              is a GNU extension.

       [1mv[22m, [1mV   [22mSet the vertical spacing to be used in a text block.  This modi‐
              fier must be followed by an integer [4mn[24m with an  optional  leading
              sign.   If  unsigned,  the  vertical spacing is set to [4mn[24m points.
              Otherwise, the vertical spacing is  incremented  or  decremented
              per  the sign by [4mn[24m points.  The use of a signed multi‐digit num‐
              ber is a GNU extension.  (This parameter corresponds to that ac‐
              cepted by the [4mtroff[24m [1mvs [22mrequest.)  If a vertical spacing modifier
              is followed by a column separation modifier  (see  below),  they
              must be separated by at least one space or tab.

       [1mw[22m, [1mW   [22mSet  the column’s minimum width.  This modifier must be followed
              by a number, which is either a unitless integer, or a [4mroff[24m hori‐
              zontal measurement in parentheses.  Parentheses are required  if
              the  width  is  to be followed immediately by an explicit column
              separation (alternatively, follow the width  with  one  or  more
              spaces  or  tabs).   If  no  unit is specified, ens are assumed.
              This modifier sets the default line length used in a text block.

       [1mx[22m, [1mX   [22mExpand the column.  After computing the column widths,  distrib‐
              ute  any  remaining  line length evenly over all columns bearing
              this modifier.  Applying the [1mx [22mmodifier to more than one  column
              is  a GNU extension.  This modifier sets the default line length
              used in a text block.

       [1mz[22m, [1mZ   [22mIgnore the table entries corresponding to this column for  width
              calculation  purposes; that is, compute the column’s width using
              only the information in its descriptor.

       [4mn[24m      A numeric suffix on a column descriptor sets the separation dis‐
              tance (in ens) from the succeeding column; the  default  separa‐
              tion is [1m3n[22m.  This separation is proportionally multiplied if the
              [1mexpand  [22mregion  option is in effect; in the case of tables wider
              than the output line length, this separation might be  zero.   A
              negative  separation  cannot  be specified.  A separation amount
              after the last column in a row is nonsensical and provokes a di‐
              agnostic from [4mtbl[24m.

   [1mTable data[0m
       The table data come after the format specification.   Each  input  line
       corresponds  to  a  table  row, except that a backslash at the end of a
       line of table data continues an entry on the next  input  line.   (Text
       blocks,  discussed below, also spread table entries across multiple in‐
       put lines.)  Table entries within a row are separated in the input by a
       tab character by default; see the [1mtab [22mregion option above.  Excess  en‐
       tries  in  a row of table data (those that have no corresponding column
       descriptor, not even an implicit one arising from rectangularization of
       the table) are discarded with a diagnostic message.  [4mroff[24m control lines
       are accepted between rows of table data and within text blocks.  If you
       wish to visibly mark an empty table entry in the document source, popu‐
       late it with the [1m\& [4m[22mroff[24m dummy character.  The table  data  are  inter‐
       rupted  by  a line consisting of the [1m.T& [22minput token, and conclude with
       the line [1m.TE[22m.

       Ordinarily, a table entry is typeset rigidly.  It is not  filled,  bro‐
       ken,  hyphenated, adjusted, or populated with additional inter‐sentence
       space.  [4mtbl[24m instructs the formatter to measure each table entry  as  it
       occurs  in  the input, updating the width required by its corresponding
       column.  If the [1mz [22mmodifier applies to the column, this  measurement  is
       ignored;  if [1mw [22mapplies and its argument is larger than this width, that
       argument is used instead.   In  contrast  to  conventional  [4mroff[24m  input
       (within a paragraph, say), changes to text formatting, such as font se‐
       lection or vertical spacing, do not persist between entries.

       Several forms of table entry are interpreted specially.

       • If a table row contains only an underscore or equals sign ([1m_ [22mor [1m=[22m), a
         single  or  double  horizontal  rule  (line),  respectively, is drawn
         across the table at that point.

       • A table entry containing only [1m_ [22mor [1m= [22mon an otherwise populated row is
         replaced by a single or double horizontal rule, respectively, joining
         its neighbors.

       • Prefixing a lone underscore or equals sign with a backslash also  has
         meaning.   If a table entry consists only of [1m\_ [22mor [1m\= [22mon an otherwise
         populated row, it is replaced by a single or double horizontal  rule,
         respectively, that does [4mnot[24m (quite) join its neighbors.

       • A table entry consisting of [1m\R[4m[22mx[24m, where [4mx[24m is any [4mroff[24m ordinary or spe‐
         cial character, is replaced by enough repetitions of the glyph corre‐
         sponding  to  [4mx[24m to fill the column, albeit without joining its neigh‐
         bors.

       • On any row but the first, a table entry of [1m\^ [22mcauses the entry  above
         it to span down into the current one.

       On  occasion,  these  special  tokens  may be required as literal table
       data.  To use either [1m_ [22mor [1m= [22mliterally and alone in an entry, prefix  or
       suffix  it with the [4mroff[24m dummy character [1m\&[22m.  To express [1m\_[22m, [1m\=[22m, or [1m\R[22m,
       use a [4mroff[24m escape sequence to interpolate the backslash ([1m\e [22mor  [1m\[rs][22m).
       A reliable way to emplace the [1m\^ [22mglyph sequence within a table entry is
       to use a pair of [4mgroff[24m special character escape sequences ([1m\[rs]\[ha][22m).

       Rows  of  table  entries  can  be interleaved with [4mgroff[24m control lines;
       these do not count as table data.  On such lines  the  default  control
       character  ([1m.[22m)  must  be  used  (and not changed); the no‐break control
       character is not recognized.  To start the first table entry in  a  row
       with a dot, precede it with the [4mroff[24m dummy character [1m\&[22m.

   [1mText blocks[0m
       An ordinary table entry’s contents can make a column, and therefore the
       table,  excessively wide; the table then exceeds the line length of the
       page, and becomes ugly or is exposed to truncation by  the  output  de‐
       vice.   When  a  table  entry  requires  more conventional typesetting,
       breaking across more than one output line (and thereby  increasing  the
       height of its row), it can be placed within a [4mtext[24m [4mblock.[0m

       [4mtbl[24m interprets a table entry beginning with “[1mT{[22m” at the end of an input
       line  not  as  table data, but as a token starting a text block.  Simi‐
       larly, “[1mT}[22m” at the start of an input line ends a text  block;  it  must
       also  end  the  table entry.  Text block tokens can share an input line
       with other table data (preceding [1mT{ [22mand following [1mT}[22m).  Input lines be‐
       tween these tokens are formatted in a diversion by [4mtroff[24m.  Text  blocks
       cannot be nested.  Multiple text blocks can occur in a table row.

       Text  blocks are formatted as was the text prior to the table, modified
       by applicable column descriptors.  Specifically, the classifiers [1mA[22m,  [1mC[22m,
       [1mL[22m,  [1mN[22m, [1mR[22m, and [1mS [22mdetermine a text block’s [4malignment[24m within its cell, but
       not its [4madjustment.[24m  Add [1mna [22mor [1mad [22mrequests to the beginning of  a  text
       block  to  alter its adjustment distinctly from other text in the docu‐
       ment.  As with other table entries, when a text block ends, any  alter‐
       ations to formatting parameters are discarded.  They do not affect sub‐
       sequent table entries, not even other text blocks.

       If [1mw [22mor [1mx [22mmodifiers are not specified for [4mall[24m columns of a text block’s
       span,  the  default  length of the text block (more precisely, the line
       length used to  process  the  text  block  diversion)  is  computed  as
       [4mL[24m×[4mC[24m/([4mN[24m+1),  where [4mL[24m is the current line length, [4mC[24m the number of columns
       spanned by the text block, and [4mN[24m the number of columns  in  the  table.
       If necessary, you can also control a text block’s width by including an
       [1mll  [22m(line length) request in it prior to any text to be formatted.  Be‐
       cause a diversion is used to format the  text  block,  its  height  and
       width  are  subsequently  available in the registers [1mdn [22mand [1mdl[22m, respec‐
       tively.

   [4m[1mroff[24m interface[0m
       The register [1mTW [22mstores the width of the table region in basic units; it
       can’t be used within the region itself, but is defined before  the  [1m.TE[0m
       token  is output so that a [4mgroff[24m macro named [1mTE [22mcan make use of it.  [1mT.[0m
       is a Boolean‐valued register indicating whether the bottom of the table
       is being processed.  The [1m#T [22mregister marks the top of the table.  Avoid
       using these names for any other purpose.

       [4mtbl[24m also defines a macro [1mT# [22mto produce the bottom and side lines  of  a
       boxed  table.   While  [4mtbl[24m  itself arranges for the output to include a
       call of this macro at the end of such a table, it can also be  used  by
       macro packages to create boxes for multi‐page tables by calling it from
       a  page  footer  macro that is itself called by a trap planted near the
       bottom of the page.  See section “Limitations” below for more on multi‐
       page tables.

       GNU [4mtbl[24m internally employs register, string, macro, and diversion names
       beginning with the numeral [1m3[22m.  A document to be preprocessed  with  GNU
       [4mtbl[24m should not use any such identifiers.

   [1mInteraction with [4meqn[0m
       [4mtbl[24m  should  always  be  called before [4meqn[24m(1).  ([4mgroff[24m(1) automatically
       arranges preprocessors in the correct order.)  Don’t call the [1mEQ [22mand [1mEN[0m
       macros within tables; instead, set up delimiters in your [4meqn[24m input  and
       use the [1mdelim [22mregion option so that [4mtbl[24m will recognize them.

   [1mGNU [4mtbl[24m enhancements[0m
       In  addition to extensions noted above, GNU [4mtbl[24m removes constraints en‐
       dured by users of AT&T [4mtbl[24m.

       • Region options can be specified in any lettercase.

       • There is no limit on the number of columns in a table, regardless  of
         their classification, nor any limit on the number of text blocks.

       • All  table  rows are considered when deciding column widths, not just
         those occurring in the first 200 input lines of a region.  Similarly,
         table continuation ([1m.T&[22m) tokens are  recognized  outside  a  region’s
         first 200 input lines.

       • Numeric and alphabetic entries may appear in the same column.

       • Numeric and alphabetic entries may span horizontally.

   [1mUsing GNU [4mtbl[24m within macros[0m
       You can embed a table region inside a macro definition.  However, since
       [4mtbl[24m writes its own macro definitions at the beginning of each table re‐
       gion, it is necessary to call end macros instead of ending macro defin‐
       itions with “[1m..[22m”.  Additionally, the escape character must be disabled.

       Not all [4mtbl[24m features can be exercised from such macros because [4mtbl[24m is a
       [4mroff[24m  preprocessor: it sees the input earlier than [4mtroff[24m does.  For ex‐
       ample, vertically aligning decimal separators fails if the numbers con‐
       taining them occur as macro or string parameters; the alignment is per‐
       formed by [4mtbl[24m itself, which sees only [1m\$1[22m, [1m\$2[22m, and so on,  and  there‐
       fore  can’t  recognize a decimal separator that only appears later when
       [4mtroff[24m interpolates a macro or string definition.

       Using [4mtbl[24m macros within conditional input (that is, contingent upon  an
       [1mif[22m,  [1mie[22m, [1mel[22m, or [1mwhile [22mrequest) can result in misleading line numbers in
       subsequent diagnostics.  [4mtbl[24m unconditionally injects  its  output  into
       the  source  document, but the conditional branch containing it may not
       be taken, and if it is not, the [1mlf [22mrequests that [4mtbl[24m injects to restore
       the source line number cannot take effect.  Consider copying the  input
       line  counter register [1mc. [22mand restoring its value at a convenient loca‐
       tion after applicable arithmetic.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-C     [22mEnable  AT&T compatibility mode: recognize [1m.TS [22mand [1m.TE [22meven when
              followed by a character other than space or  newline.   Further‐
              more, interpret the uninterpreted leader escape sequence [1m\a[22m.

[1mLimitations[0m
       Multi‐page  tables,  if  boxed and/or if you want their column headings
       repeated after page breaks, require support at the time the document is
       formatted.  A convention for such support has arisen in macro  packages
       such  as  [4mms[24m, [4mmm[24m, and [4mme[24m.  To use it, follow the [1m.TS [22mtoken with a space
       and then “[1mH[22m”; this will be interpreted by the formatter as a  [1mTS  [22mmacro
       call  with  an  [1mH  [22margument.   Then, within the table data, call the [1mTH[0m
       macro; this informs the macro package where the headings end.  If  your
       table  has no such heading rows, or you do not desire their repetition,
       call [1mTH [22mimmediately after the table format specification.  If a  multi‐
       page table is boxed or has repeating column headings, do not enclose it
       with  keep/release macros, or divert it in any other way.  Further, the
       [1mbp [22mrequest will not cause a page break in a “[1mTS  H[22m”  table.   Define  a
       macro  to wrap [1mbp[22m: invoke it normally if there is no current diversion.
       Otherwise, pass the macro call to the  enclosing  diversion  using  the
       transparent  line  escape  sequence  [1m\![22m; this will “bubble up” the page
       break to the output device.  See section “Examples” below for a  demon‐
       stration.

       Double  horizontal  rules  are not supported by [4mgrotty[24m(1); single rules
       are used instead.  [4mgrotty[24m also ignores half‐line motions, so the [1mu [22mcol‐
       umn modifier has no effect.  On terminal devices (“[4mnroff[24m mode”),  hori‐
       zontal rules and box borders occupy a full vee of space; this amount is
       doubled for [1mdoublebox [22mtables.  Tables using these features thus require
       more vertical space in [4mnroff[24m mode than in [4mtroff[24m mode: write [1mne [22mrequests
       accordingly.  Vertical rules between columns are drawn in the space be‐
       tween  columns in [4mnroff[24m mode; using double vertical rules and/or reduc‐
       ing the column separation below the default can make them ugly or over‐
       strike them with table data.

       A text block within a table must be able to fit on one page.

       Using [1m\a [22mto put leaders in table entries does not work in GNU [4mtbl[24m,  ex‐
       cept  in  compatibility mode.  This is correct behavior: [1m\a [22mis an [4munin‐[0m
       [4mterpreted[24m leader.  You can still use the [4mroff[24m  leader  character  (Con‐
       trol+A)  or  define a string to use [1m\a [22mas it was designed: to be inter‐
       preted only in copy mode.

              .ds a \a
              .TS
              box center tab(;);
              Lw(2i)0 L.
              Population\*a;6,327,119
              .TE

                         ┌───────────────────────────────┐
                         │ Population..........6,327,119 │
                         └───────────────────────────────┘

       A leading  and/or  trailing  [1m|  [22min  a  format  specification,  such  as
       “[1m|LCR|.[22m”,  produces an en space between the vertical rules and the con‐
       tent of the adjacent columns.  If no such space is desired (so that the
       rule abuts the content), you can introduce “dummy”  columns  with  zero
       separation and empty corresponding table entries before and/or after.

              .TS
              center tab(#);
              R0|L C R0|L.
              _
              #levulose#glucose#dextrose#
              _
              .TE

       These dummy columns have zero width and are therefore invisible; unfor‐
       tunately they usually don’t work as intended on terminal devices.

[1mExamples[0m
       It  can  be easier to acquire the language of [4mtbl[24m through examples than
       formal description, especially at first.

              .TS
              box center tab(#);
              Cb Cb
              L L.
              Ability#Application
              Strength#crushes a tomato
              Dexterity#dodges a thrown tomato
              Constitution#eats a month‐old tomato without becoming ill
              Intelligence#knows that a tomato is a fruit
              Wisdom#chooses \f[I]not\f[] to put tomato in a fruit salad
              Charisma#sells obligate carnivores tomato‐based fruit salads
              .TE

       ┌────────────────────────────────────────────────────────────────────┐
       │   [1mAbility                          Application                     [22m│
       │ Strength       crushes a tomato                                    │
       │ Dexterity      dodges a thrown tomato                              │
       │ Constitution   eats a month‐old tomato without becoming ill        │
       │ Intelligence   knows that a tomato is a fruit                      │
       │ Wisdom         chooses [4mnot[24m to put tomato in a fruit salad          │
       │ Charisma       sells obligate carnivores tomato‐based fruit salads │
       └────────────────────────────────────────────────────────────────────┘

       The [1mA [22mand [1mN [22mcolumn classifiers can be easier to grasp in visual render‐
       ing than in description.

              .TS
              center tab(;);
              CbS,LN,AN.
              Daily energy intake (in MJ)
              Macronutrients
              .\" assume 3 significant figures of precision
              Carbohydrates;4.5
              Fats;2.25
              Protein;3
              .T&
              LN,AN.
              Mineral
              Pu-239;14.6
              _
              .T&
              LN.
              Total;\[ti]24.4
              .TE

                                [1mDaily energy intake (in MJ)[0m
                                Macronutrients
                                  Carbohydrates       4.5
                                  Fats                2.25
                                  Protein             3
                                Mineral
                                  Pu‐239             14.6
                                ────────────────────────────
                                Total               ~24.4

       Next, we’ll lightly adapt a compact presentation of spanning,  vertical
       alignment,  and  zero‐width  column modifiers from the [4mmandoc[24m reference
       for its [4mtbl[24m interpreter.  It rewards close study.

              .TS
              box center tab(:);
              Lz  S | Rt
              Ld| Cb| ^
              ^ | Rz  S.
              left:r
              l:center:
              :right
              .TE

                                    ┌────────────┬───┐
                                    │ le│ft       │ r │
                                    │   │ [1mcenter [22m│   │
                                    │ l │      right │
                                    └───┴────────────┘

       Row staggering is not visually achievable on terminal  devices,  but  a
       table using it can remain comprehensible nonetheless.

              .TS
              center tab(|);
              Cf(BI) Cf(BI) Cf(B), C C Cu.
              n|n\f[B]\[tmu]\f[]n|difference
              1|1
              2|4|3
              3|9|5
              4|16|7
              5|25|9
              6|36|11
              .TE

                                    [4m[1mn[24m   [4mn[24m×[4mn[24m   difference[0m
                                    1    1
                                    2    4        3
                                    3    9        5
                                    4   16        7
                                    5   25        9
                                    6   36        11

       Some [4mtbl[24m features cannot be illustrated in the limited environment of a
       portable man page.

       We  can  define  a  macro outside of a [4mtbl[24m region that we can call from
       within it to cause a page break inside a multi‐page boxed  table.   You
       can  choose  a  different  name;  be sure to change both occurrences of
       “BP”.

              .de BP
              .  ie '\\n(.z'' .bp \\$1
              .  el \!.BP \\$1
              ..

[1mSee also[0m
       “Tbl—A Program to Format Tables”, by M. E. Lesk, 1976 (revised 16 Janu‐
       ary 1979), AT&T Bell Laboratories Computing  Science  Technical  Report
       No. 49.

       The spanning example above was taken from [4mmandoc[24m’s man page for its [4mtbl[0m
       implementation ⟨https://man.openbsd.org/tbl.7⟩.

       [4mgroff[24m(1), [4mtroff[24m(1)

groff 1.23.0                      5 July 2023                           [4mtbl[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mtfmtodit[24m(1)                 General Commands Manual                [4mtfmtodit[24m(1)

[1mName[0m
       tfmtodit - adapt TeX Font Metrics files for use with [4mgroff[24m and [4mgrodvi[0m

[1mSynopsis[0m
       [1mtfmtodit [22m[[1m-s[22m] [[1m-g [4m[22mgf‐file[24m] [[1m-k [4m[22mskew‐char[24m] [4mtfm‐file[24m [4mmap‐file[24m [4mfont‐[0m
                [4mdescription[0m

       [1mtfmtodit --help[0m

       [1mtfmtodit -v[0m
       [1mtfmtodit --version[0m

[1mDescription[0m
       [4mtfmtodit[24m  creates  a  font description file for use with [4mgroff[24m(1)’s [1mdvi[0m
       output device.  [4mtfm‐file[24m is the name of the TeX font  metric  file  for
       the font.  [4mmap‐file[24m assigns [4mgroff[24m ordinary or special character identi‐
       fiers  to glyph indices in the font; it should consist of a sequence of
       lines of the form
              [4mi[24m [4mc1[24m ... [4mcn[0m
       where [4mi[24m is a position of the glyph in  the  font  in  decimal,  and  [4mc1[0m
       through  [4mcn[24m  are  glyph  identifiers in the form used by [4mgroff[24m font de‐
       scriptions.  If a glyph has no [4mgroff[24m names but exists in  [4mtfm‐file,[24m  it
       is  put in the [4mgroff[24m font description file as an unnamed glyph.  Output
       is written in [4mgroff_font[24m(5) format to [4mfont‐description,[24m  a  file  named
       for the intended [4mgroff[24m font name.

       If  the font is “special”, meaning that [4mgroff[24m should search it whenever
       a glyph is not found in the current font, use the [1m-s  [22moption  and  name
       [4mfont‐description[24m  in  the  [1mfonts  [22mdirective in the output device’s [4mDESC[0m
       file.

       To do a good job of math typesetting, [4mgroff[24m requires font metric infor‐
       mation not present in [4mtfm‐file.[24m  This is because TeX has separate  math
       italic fonts, whereas [4mgroff[24m uses normal italic fonts for math.  The ad‐
       ditional information required by [4mgroff[24m is given by the two arguments to
       the  [1mmath_fit  [22mmacro  in  the Metafont programs for the Computer Modern
       fonts.  In a text font (a font for which [1mmath_fit [22mis  false),  Metafont
       normally ignores these two arguments.  Metafont can be made to put this
       information  into  the GF (“generic font”) files it produces by loading
       the following definition after [1mcmbase [22mwhen creating [4mcm.base[24m.
              def ignore_math_fit(expr left_adjustment,right_adjustment) =
                  special "adjustment";
                  numspecial left_adjustment*16/designsize;
                  numspecial right_adjustment*16/designsize;
                  enddef;
       For the EC font family, load the  following  definition  after  [1mexbase[22m;
       consider patching [4mexbase.mf[24m locally.
              def ignore_math_fit(expr left_adjustment,right_adjustment) =
                  ori_special "adjustment";
                  ori_numspecial left_adjustment*16/designsize;
                  ori_numspecial right_adjustment*16/designsize;
                  enddef;
       The  only  difference from the previous example is the “ori_” prefix to
       “special” and “numspecial”.  The GF file created  using  this  modified
       [4mcm.base[24m  or  [4mexbase.mf[24m  should  be  specified with the [1m-g [22moption, which
       should [4mnot[24m be given for a font for which [1mmath_fit [22mis true.

[1mOptions[0m
       [1m--help [22mdisplays a usage message, while [1m-v [22mand  [1m--version  [22mshow  version
       information; all exit afterward.

       [1m-g [4m[22mgf‐file[0m
              Use  the  [4mgf‐file[24m  produced by Metafont containing “[1mspecial[22m” and
              “[1mnumspecial[22m” commands to obtain additional font metric  informa‐
              tion.

       [1m-k [4m[22mskew‐char[0m
              The skew character of this font is at position [4mskew‐char.[24m  [4mskew‐[0m
              [4mchar[24m  should  be  an integer; it may be given in decimal, with a
              leading 0 in octal, or with a leading 0x  in  hexadecimal.   Any
              kerns whose second component is [4mskew‐char[24m are ignored.

       [1m-s     [22mAdd the [1mspecial [22mdirective to the font description file.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/DESC[0m
              describes the [1mdvi [22moutput device.

       [4m/usr/share/groff/1.23.0/font/devdvi/[24mF
              describes the font known as [4mF[24m on device [1mdvi[22m.

       [4m/usr/share/groff/1.23.0/font/devdvi/generate/ec.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/msam.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/msbm.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/tc.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texb.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texex.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texi.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texitt.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texmi.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texr.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/texsy.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/textex.map[0m
       [4m/usr/share/groff/1.23.0/font/devdvi/generate/textt.map[0m
              map  glyph  indices  in  TeX fonts to [4mgroff[24m ordinary and special
              character identifiers.  [4mec.map[24m is used  for  [1mTREC[22m,  [1mTIEC[22m,  [1mTBEC[22m,
              [1mTBIEC[22m,  [1mHREC[22m,  [1mHIEC[22m,  [1mHBEC[22m, [1mHBIEC[22m, [1mCWEC[22m, and [1mCWIEC[22m; [4mmsam.map[24m for
              [1mSA[22m; [4mmsbm.map[24m for [1mSB[22m; [4mtc.map[24m for [1mTRTC[22m, [1mTITC[22m, [1mTBTC[22m,  [1mTBITC[22m,  [1mHRTC[22m,
              [1mHITC[22m, [1mHBTC[22m, [1mHBITC[22m, [1mCWTC[22m, and [1mCWITC[22m; [4mtexb.map[24m for [1mTB[22m, [1mHR[22m, [1mHI[22m, [1mHB[22m,
              and  [1mHBI[22m;  [4mtexex.map[24m for [1mEX[22m; [4mtexi.map[24m for [1mTI [22mand [1mTBI[22m; [4mtexitt.map[0m
              for [1mCWI[22m; [4mtexmi.map[24m for [1mMI[22m; [4mtexr.map[24m for  [1mTR[22m;  [4mtexsy.map[24m  for  [1mS[22m;
              [4mtextex.map[24m for [1mSC[22m; and [4mtextt.map[24m for [1mCW[22m.

[1mSee also[0m
       [4mgroff[24m(1), [4mgrodvi[24m(1), [4mgroff_font[24m(5)

groff 1.23.0                      5 July 2023                      [4mtfmtodit[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mtroff[24m(1)                    General Commands Manual                   [4mtroff[24m(1)

[1mName[0m
       troff - GNU [4mroff[24m typesetter and document formatter

[1mSynopsis[0m
       [1mtroff [22m[[1m-abcCEiRUz[22m] [[1m-d [4m[22mctext[24m] [[1m-d [4m[22mstring[24m[1m=[4m[22mtext[24m] [[1m-f [4m[22mfont‐family[24m]
             [[1m-F [4m[22mfont‐directory[24m] [[1m-I [4m[22minclusion‐directory[24m] [[1m-m [4m[22mmacro‐package[24m]
             [[1m-M [4m[22mmacro‐directory[24m] [[1m-n [4m[22mpage‐number[24m] [[1m-o [4m[22mpage‐list[24m]
             [[1m-r [4m[22mcnumeric‐expression[24m] [[1m-r [4m[22mregister[24m[1m=[4m[22mnumeric‐expression[24m]
             [[1m-T [4m[22moutput‐device[24m] [[1m-w [4m[22mwarning‐category[24m] [[1m-W [4m[22mwarning‐category[24m]
             [[4mfile[24m ...]

       [1mtroff --help[0m

       [1mtroff -v[0m
       [1mtroff --version[0m

[1mDescription[0m
       GNU  [4mtroff[24m  transforms [4mgroff[24m(7) language input into the device‐indepen‐
       dent output format described in [4mgroff_out[24m(5); [4mtroff[24m is thus  the  heart
       of  the  GNU  [4mroff[24m document formatting system.  If no [4mfile[24m operands are
       given on the command line, or if [4mfile[24m is “[1m-[22m”, the standard input stream
       is read.

       GNU [4mtroff[24m is functionally compatible with the AT&T [4mtroff[24m typesetter and
       features numerous extensions.  Many people prefer to use  the  [4mgroff[24m(1)
       command,  a  front end which also runs preprocessors and output drivers
       in the appropriate order and with appropriate options.

[1mOptions[0m
       [1m-h [22mand [1m--help [22mdisplay a usage message, while [1m-v [22mand [1m--version [22mshow ver‐
       sion information; all exit afterward.

       [1m-a     [22mGenerate a plain text approximation of the typeset output.   The
              read‐only  register [1m.A [22mis set to 1.  This option produces a sort
              of abstract preview of the formatted output.

              • Page breaks are marked by a phrase in angle brackets; for  ex‐
                ample, “<beginning of page>”.

              • Lines are broken where they would be in the formatted output.

              • A  horizontal  motion of any size is represented as one space.
                Adjacent horizontal motions are not combined.   Inter‐sentence
                space nodes (those arising from the second argument to the [1m.ss[0m
                request) are not represented.

              • Vertical motions are not represented.

              • Special  characters  are rendered in angle brackets; for exam‐
                ple, the default soft hyphen character appears as “<hy>”.

              The above description should not be considered a  specification;
              the details of [1m-a [22moutput are subject to change.

       [1m-b     [22mWrite a backtrace reporting the state of [4mtroff[24m’s input parser to
              the  standard  error  stream  with each diagnostic message.  The
              line numbers given in the backtrace might not always be correct,
              because [4mtroff[24m’s idea of line numbers can be confused by requests
              that append to macros.

       [1m-c     [22mStart with color output disabled.

       [1m-C     [22mEnable  AT&T  [4mtroff[24m  compatibility  mode;   implies   [1m-c[22m.    See
              [4mgroff_diff[24m(7).

       [1m-d [4m[22mctext[0m
       [1m-d [4m[22mstring[24m[1m=[4m[22mtext[0m
              Define  [4mroff[24m  string [4mc[24m or [4mstring[24m as [4mtext.[24m  [4mc[24m must be one charac‐
              ter; [4mstring[24m can be of arbitrary length.  Such string assignments
              happen before any macro file is loaded,  including  the  startup
              file.   Due  to  [4mgetopt_long[24m(3)  limitations,  [4mc[24m  cannot be, and
              [4mstring[24m cannot contain, an equals sign, even  though  that  is  a
              valid character in a [4mroff[24m identifier.

       [1m-E     [22mInhibit [4mtroff[24m error messages; implies [1m-Ww[22m.  This option does [4mnot[0m
              suppress messages sent to the standard error stream by documents
              or macro packages using [1mtm [22mor related requests.

       [1m-f [4m[22mfam[24m Use [4mfam[24m as the default font family.

       [1m-F [4m[22mdir[24m Search  in directory [4mdir[24m for the selected output device’s direc‐
              tory of device and font description files.  See the  description
              of  [4mGROFF_FONT_PATH[24m  in  section “Environment” below for the de‐
              fault search locations and ordering.

       [1m-i     [22mRead the standard input stream after all named input files  have
              been processed.

       [1m-I [4m[22mdir[24m Search  the  directory [4mdir[24m for files (those named on the command
              line; in [1mpsbb[22m, [1mso[22m, and [1msoquiet  [22mrequests;  and  in  “[1m\X'ps:  im‐[0m
              [1mport'[22m”, “[1m\X'ps: file'[22m”, and “[1m\X'pdf: pdfpic'[22m” device control es‐
              cape  sequences).   [1m-I [22mmay be specified more than once; each [4mdir[0m
              is searched in the given order.  To search the  current  working
              directory  before others, add “[1m-I .[22m” at the desired place; it is
              otherwise searched last.  [1m-I [22mworks similarly to,  and  is  named
              for, the “include” option of Unix C compilers.

       [1m-m [4m[22mname[0m
              Process  the  file  name[4m.tmac[24m  prior to any input files.  If not
              found, [4mtmac.[24mname is attempted.  [4mname[24m (in both  arrangements)  is
              presumed   to   be   a   macro  file;  see  the  description  of
              [4mGROFF_TMAC_PATH[24m in section “Environment” below for  the  default
              search locations and ordering.

       [1m-M [4m[22mdir[24m Search  directory  [4mdir[24m  for macro files.  See the description of
              [4mGROFF_TMAC_PATH[24m in section “Environment” below for  the  default
              search locations and ordering.

       [1m-n [4m[22mnum[24m Begin numbering pages at [4mnum.[24m  The default is [1m1[22m.

       [1m-o [4m[22mlist[0m
              Output  only  pages  in [4mlist,[24m which is a comma‐separated list of
              inclusive page ranges; [4mn[24m means page [4mn,[24m [4mm[24m[1m-[4m[22mn[24m means every page  be‐
              tween  [4mm[24m  and [4mn[24m, [1m-[4m[22mn[24m means every page up to [4mn[24m, and [4mn[24m[1m- [22mmeans every
              page from [4mn[24m on.  [4mtroff[24m stops processing and exits after  format‐
              ting the last page enumerated in [4mlist.[0m

       [1m-r [4m[22mcnumeric‐expression[0m
       [1m-r [4m[22mregister[24m[1m=[4m[22mnumeric‐expression[0m
              Define  [4mroff[24m  register  [4mc[24m  or  [4mregister[24m  as  [4mnumeric‐expression.[0m
              [4mc[24m must be a one‐character name; [4mregister[24m  can  be  of  arbitrary
              length.   Such register assignments happen before any macro file
              is loaded, including the startup file.   Due  to  [4mgetopt_long[24m(3)
              limitations, [4mc[24m cannot be, and [4mregister[24m cannot contain, an equals
              sign,  even  though  that is a valid character in a [4mroff[24m identi‐
              fier.

       [1m-R     [22mDon’t load [4mtroffrc[24m and [4mtroffrc-end[24m.

       [1m-T [4m[22mdev[24m Prepare output for device [4mdev.[24m  The default is [1mps[22m; see [4mgroff[24m(1).

       [1m-U     [22mOperate in [4munsafe[24m [4mmode,[24m enabling the [1mopen[22m, [1mopena[22m, [1mpi[22m,  [1mpso[22m,  and
              [1msy [22mrequests, which are disabled by default because they allow an
              untrusted  input  document  to write to arbitrary file names and
              run arbitrary commands.  This option also adds the  current  di‐
              rectory  to the macro package search path; see the [1m-m [22mand [1m-M [22mop‐
              tions above.

       [1m-w [4m[22mname[0m
       [1m-W [4m[22mname[0m
              Enable ([1m-w[22m) or inhibit ([1m-W[22m) warnings in category [4mname.[24m  See sec‐
              tion “Warnings” below.

       [1m-z     [22mSuppress formatted output.

[1mWarnings[0m
       Warning diagnostics emitted by [4mtroff[24m are divided into  named,  numbered
       categories.   The name associated with each warning category is used by
       the [1m-w [22mand [1m-W [22moptions.  Each category is also assigned a power of  two;
       the  sum  of enabled category codes is used by the [1mwarn [22mrequest and the
       [1m.warn [22mregister.  Warnings of each category are produced under the  fol‐
       lowing circumstances.

              ┌───────────────────────┬─────────────────────────────┐
              │ Bit   Code   Category │ Bit    Code      Category   │
              ├───────────────────────┼─────────────────────────────┤
              │   0      [4m1[24m   [1mchar     [22m│  10      [4m1024[24m   [1mreg         [22m│
              │   1      [4m2[24m   [1mnumber   [22m│  11      [4m2048[24m   [1mtab         [22m│
              │   2      [4m4[24m   [1mbreak    [22m│  12      [4m4096[24m   [1mright-brace [22m│
              │   3      [4m8[24m   [1mdelim    [22m│  13      [4m8192[24m   [1mmissing     [22m│
              │   4     [4m16[24m   [1mel       [22m│  14     [4m16384[24m   [1minput       [22m│
              │   5     [4m32[24m   [1mscale    [22m│  15     [4m32768[24m   [1mescape      [22m│
              │   6     [4m64[24m   [1mrange    [22m│  16     [4m65536[24m   [1mspace       [22m│
              │   7    [4m128[24m   [1msyntax   [22m│  17    [4m131072[24m   [1mfont        [22m│
              │   8    [4m256[24m   [1mdi       [22m│  18    [4m262144[24m   [1mig          [22m│
              │   9    [4m512[24m   [1mmac      [22m│  19    [4m524288[24m   [1mcolor       [22m│
              │                       │  20   [4m1048576[24m   [1mfile        [22m│
              └───────────────────────┴─────────────────────────────┘

       [1mbreak           [22m4   A  filled output line could not be broken such that
                           its length was less than  the  output  line  length
                           [1m\n[.l][22m.  This category is enabled by default.

       [1mchar            [22m1   No  mounted  font defines a glyph for the requested
                           character.  This category is enabled by default.

       [1mcolor      [22m524288   An undefined color name was  selected,  an  attempt
                           was  made  to  define a color using an unrecognized
                           color space, an invalid component in a color defin‐
                           ition was encountered, or an attempt  was  made  to
                           redefine a default color.

       [1mdelim           [22m8   The  closing  delimiter  in  an escape sequence was
                           missing or mismatched.

       [1mdi            [22m256   A [1mdi[22m, [1mda[22m, [1mbox[22m, or [1mboxa [22mrequest was invoked  without
                           an argument when there was no current diversion.

       [1mel             [22m16   The [1mel [22mrequest was encountered with no prior corre‐
                           sponding [1mie [22mrequest.

       [1mescape      [22m32768   An unsupported escape sequence was encountered.

       [1mfile      [22m1048576   An  attempt  was  made to load a file that does not
                           exist.  This category is enabled by default.

       [1mfont       [22m131072   A non‐existent font was selected, or the  selection
                           was  ignored  because  a  font selection escape se‐
                           quence was used after the output line  continuation
                           escape sequence on an input line.  This category is
                           enabled by default.

       [1mig         [22m262144   An  invalid  escape  sequence occurred in input ig‐
                           nored using the [1mig [22mrequest.  This warning  category
                           diagnoses  a condition that is an error when it oc‐
                           curs in non‐ignored input.

       [1minput       [22m16384   An invalid character occurred on the input stream.

       [1mmac           [22m512   An undefined string, macro, or diversion was  used.
                           When  such  an object is dereferenced, an empty one
                           of that name is automatically created.  So,  unless
                           it  is  later deleted, at most one warning is given
                           for each.

                           This warning is also emitted  upon  an  attempt  to
                           move  an  unplanted trap macro.  In such cases, the
                           unplanted macro is [4mnot[24m dereferenced, so it  is  not
                           created if it does not exist.

       [1mmissing      [22m8192   A request was invoked with a mandatory argument ab‐
                           sent.

       [1mnumber          [22m2   An  invalid  numeric  expression  was  encountered.
                           This category is enabled by default.

       [1mrange          [22m64   A numeric expression was out of range for its  con‐
                           text.

       [1mreg          [22m1024   An  undefined register was used.  When an undefined
                           register is dereferenced, it is  automatically  de‐
                           fined  with  a  value of 0.  So, unless it is later
                           deleted, at most one warning is given for each.

       [1mright-brace  [22m4096   A right brace escape sequence  [1m\}  [22mwas  encountered
                           where a number was expected.

       [1mscale          [22m32   A  scaling  unit  inappropriate  to its context was
                           used in a numeric expression.

       [1mspace       [22m65536   A space was missing between a request or macro  and
                           its argument.  This warning is produced when an un‐
                           defined  name longer than two characters is encoun‐
                           tered and the first two characters of the name con‐
                           stitute a defined name.  No request is invoked,  no
                           macro  called,  and  an empty macro is not defined.
                           This category is enabled by default.  It never  oc‐
                           curs in compatibility mode.

       [1msyntax        [22m128   A   self‐contradictory  hyphenation  mode  was  re‐
                           quested; an empty or incomplete numeric  expression
                           was  encountered;  an operand to a numeric operator
                           was missing; an attempt was made to define a recur‐
                           sive, empty, or nonsensical character class;  or  a
                           [4mgroff[24m extension conditional expression operator was
                           used while in compatibility mode.

       [1mtab          [22m2048   A  tab character was encountered where a number was
                           expected, or appeared in an  unquoted  macro  argu‐
                           ment.

       Two warning names group other warning categories for convenience.

       [1mall    [22mAll  warning categories except [1mdi[22m, [1mmac[22m, and [1mreg[22m.  This shorthand
              is intended to produce all warnings that are useful  with  macro
              packages  and  documents  written for AT&T [4mtroff[24m and its descen‐
              dants, which have less fastidious diagnostics than GNU [4mtroff[24m.

       [1mw      [22mAll warning categories.  Authors of documents and macro packages
              targeting [4mgroff[24m are encouraged to use this setting.

[1mEnvironment[0m
       [4mGROFF_FONT_PATH[24m and [4mGROFF_TMAC_PATH[24m each accept a search path of direc‐
       tories; that is, a list of directory names separated  by  the  system’s
       path component separator character.  On Unix systems, this character is
       a colon (:); on Windows systems, it is a semicolon (;).

       [4mGROFF_FONT_PATH[0m
              A  list  of directories in which to seek the selected output de‐
              vice’s directory of device and font  description  files.   [4mtroff[0m
              will scan directories given as arguments to any specified [1m-F [22mop‐
              tions  before  these,  then  in a site‐specific directory ([4m/usr/[0m
              [4mshare/groff/site-font[24m), a standard  location  ([4m/usr/share/groff/[0m
              [4m1.23.0/font[24m),  and a compatibility directory ([4m/usr/lib/font[24m) af‐
              ter them.

       [4mGROFF_TMAC_PATH[0m
              A list of directories in which to search for macro files.  [4mtroff[0m
              will scan directories given as arguments to any specified [1m-M [22mop‐
              tions before these, then the current directory (only if  in  un‐
              safe mode), the user’s home directory, a site‐specific directory
              ([4m/usr/share/groff/site-tmac[24m),  and  a  standard  location ([4m/usr/[0m
              [4mshare/groff/1.23.0/tmac[24m) after them.

       [4mGROFF_TYPESETTER[0m
              Set the default output device.  If empty or not set, [1mps [22mis used.
              The [1m-T [22moption overrides [4mGROFF_TYPESETTER[24m.

       [4mSOURCE_DATE_EPOCH[0m
              A timestamp (expressed as seconds since the Unix epoch)  to  use
              as  the  output creation timestamp in place of the current time.
              The time is converted to human‐readable form using  [4mlocaltime[24m(3)
              when  the  formatter starts up and stored in registers usable by
              documents and macro packages.

       [4mTZ[24m     The timezone to use when converting the current time  (or  value
              of [4mSOURCE_DATE_EPOCH[24m) to human‐readable form; see [4mtzset[24m(3).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/troffrc[0m
              is an initialization macro file loaded before any macro packages
              specified with [1m-m [22moptions.

       [4m/usr/share/groff/1.23.0/tmac/troffrc-end[0m
              is  an initialization macro file loaded after all macro packages
              specified with [1m-m [22moptions.

       [4m/usr/share/groff/1.23.0/tmac/[24mname[4m.tmac[0m
              are macro files distributed with [4mgroff[24m.

       [4m/usr/share/groff/1.23.0/font/dev[24mname[4m/DESC[0m
              describes the output device [4mname[24m.

       [4m/usr/share/groff/1.23.0/font/dev[24mname[4m/[24mF
              describes the font [4mF[24m of device [4mname.[0m

       [4mtroffrc[24m and [4mtroffrc-end[24m are sought neither in the current nor the  home
       directory  by  default  for  security reasons, even if the [1m-U [22moption is
       specified.  Use the [1m-M [22mcommand‐line option or the [4mGROFF_TMAC_PATH[24m envi‐
       ronment variable to add these directories to the search path if  neces‐
       sary.

[1mAuthors[0m
       The GNU version of [4mtroff[24m was originally written by James Clark; he also
       wrote  the  original  version  of  this  document, which was updated by
       Werner Lemberg ⟨wl@gnu.org⟩,  Bernd  Warken  ⟨groff-bernd.warken-72@web
       .de⟩, and G. Branden Robinson ⟨g.branden.robinson@gmail.com⟩.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       [4mgroff[24m(1)
              offers  an  overview  of  the  GNU [4mroff[24m system and describes its
              front end executable.

       [4mgroff[24m(7)
              details the [4mgroff[24m language, including a short but complete  ref‐
              erence  of  all  predefined  requests, registers, and escape se‐
              quences.

       [4mgroff_char[24m(7)
              explains the syntax of [4mgroff[24m special character escape sequences,
              and lists all special characters predefined by the language.

       [4mgroff_diff[24m(7)
              enumerates the differences between AT&T device‐independent [4mtroff[0m
              and [4mgroff[24m.

       [4mgroff_font[24m(5)
              covers the format of [4mgroff[24m device and font description files.

       [4mgroff_out[24m(5)
              describes the format of [4mtroff[24m’s output.

       [4mgroff_tmac[24m(5)
              includes information about macro files that ship with [4mgroff[24m.

       [4mroff[24m(7)
              supplies background on [4mroff[24m systems in general, including point‐
              ers to further related documentation.

groff 1.23.0                      5 July 2023                         [4mtroff[24m(1)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_font[24m(5)                 File Formats Manual                [4mgroff_font[24m(5)

[1mName[0m
       groff_font - GNU [4mroff[24m device and font description files

[1mDescription[0m
       The [4mgroff[24m font and output device description formats are slight  exten‐
       sions  of  those used by AT&T device‐independent [4mtroff[24m.  In distinction
       to the AT&T implementation, [4mgroff[24m lacks a binary format; all files  are
       text  files.  (Plan 9 [4mtroff[24m has also abandoned the binary format.)  The
       device and font description files for a device [4mname[24m are stored in a [4mde‐[0m
       [4mv[24mname directory.  The device description file is called [4mDESC[24m, and,  for
       each font supported by the device, a font description file is called [4mf,[0m
       where  [4mf[24m is usually an abbreviation of a font’s name and/or style.  For
       example, the [1mps [22m(PostScript) device has [4mgroff[24m  font  description  files
       for Times roman ([1mTR[22m) and Zapf Chancery Medium italic ([1mZCMI[22m), among many
       others,  while  the  [1mutf8 [22mdevice (for terminal emulators) has only font
       descriptions for the roman, italic, bold, and bold‐italic styles ([1mR[22m, [1mI[22m,
       [1mB[22m, and [1mBI[22m, respectively).

       Device and font description files are read by the formatter, [4mtroff[24m, and
       by output drivers.  The programs typically delegate these  files’  pro‐
       cessing to an internal library, [4mlibgroff[24m, ensuring their consistent in‐
       terpretation.

[4m[1mDESC[24m file format[0m
       The  [4mDESC[24m  file  contains  a  series of directives; each begins a line.
       Their order is not important, with two exceptions: (1) the  [1mres  [22mdirec‐
       tive  must  precede any [1mpapersize [22mdirective; and (2) the [1mcharset [22mdirec‐
       tive must come last (if at all).  If  a  directive  name  is  repeated,
       later entries in the file override previous ones (except that the paper
       dimensions  are  computed  based  on  the  [1mres [22mdirective last seen when
       [1mpapersize [22mis encountered).  Spaces and/or tabs separate words  and  are
       ignored  at line boundaries.  Comments start with the “[1m#[22m” character and
       extend to the end of a line.  Empty lines are ignored.

       [1mfamily [4m[22mfam[0m
              The default font family is [4mfam[24m.

       [1mfonts [4m[22mn[24m [4mF1[24m ... [4mFn[0m
              Fonts [4mF1[24m, ..., [4mFn[24m are mounted at font positions  [4mm[24m+1,  ...,  [4mm[24m+[4mn[0m
              where [4mm[24m is the number of [1mstyles [22m(see below).  This directive may
              extend over more than one line.  A font name of [1m0 [22mcauses no font
              to be mounted at the corresponding position.

       [1mhor [4m[22mn[24m  The  horizontal  motion  quantum  is  [4mn[24m basic units.  Horizontal
              quantities are rounded to multiples of [4mn.[0m

       [1mimage_generator [4m[22mprogram[0m
              Use [4mprogram[24m to generate PNG images from PostScript input.  Under
              GNU/Linux, this is usually [4mgs[24m(1), but under other  systems  (no‐
              tably  Cygwin)  it might be set to another name.  The [4mgrohtml[24m(1)
              driver uses this directive.

       [1mpaperlength [4m[22mn[0m
              The vertical dimension of the output medium  is  [4mn[24m  basic  units
              (deprecated: use [1mpapersize [22minstead).

       [1mpapersize [4m[22mformat‐or‐dimension‐pair‐or‐file‐name[24m ...
              The  dimensions of the output medium are as according to the ar‐
              gument, which is either a standard paper format, a pair  of  di‐
              mensions,  or the name of a plain text file containing either of
              the foregoing.  Recognized paper formats are  the  ISO  and  DIN
              formats [1mA0[22m–[1mA7[22m, [1mB0[22m–[1mB7[22m, [1mC0[22m–[1mC7[22m, and [1mD0[22m–[1mD7[22m; the U.S. formats [1mletter[22m,
              [1mlegal[22m,  [1mtabloid[22m, [1mledger[22m, [1mstatement[22m, and [1mexecutive[22m; and the enve‐
              lope formats [1mcom10[22m, [1mmonarch[22m,  and  [1mDL[22m.   Matching  is  performed
              without regard for lettercase.

              Alternatively,  the  argument  can  be  a  custom  paper  format
              [4mlength[24m[1m,[4m[22mwidth[24m (with no spaces before or after the  comma).   Both
              [4mlength[24m  and [4mwidth[24m must have a unit appended; valid units are “[1mi[22m”
              for inches, “[1mc[22m” for centimeters, “[1mp[22m” for points, and “[1mP[22m” for pi‐
              cas.  Example: “[1m12c,235p[22m”.  An argument that starts with a digit
              is always treated as a custom paper format.

              Finally, the argument can be a file name (e.g., [4m/etc/papersize[24m);
              if the file can be opened, the first line is read  and  a  match
              attempted  against  each  other form.  No comment syntax is sup‐
              ported.

              More than one argument can be specified; each is scanned in turn
              and the first valid paper specification used.

       [1mpaperwidth [4m[22mn[0m
              The horizontal dimension of the output medium is [4mn[24m  basic  units
              (deprecated: use [1mpapersize [22minstead).

       [1mpass_filenames[0m
              Direct  [4mtroff[24m  to  emit  the  name  of  the  source  file  being
              processed.  This is achieved with the intermediate  output  com‐
              mand “[1mx F[22m”, which [4mgrohtml[24m interprets.

       [1mpostpro [4m[22mprogram[0m
              Use [4mprogram[24m as the postprocessor.

       [1mprepro [4m[22mprogram[0m
              Use  [4mprogram[24m  as  a preprocessor.  The [1mhtml [22mand [1mxhtml [22moutput de‐
              vices use this directive.

       [1mprint [4m[22mprogram[0m
              Use [4mprogram[24m as the print spooler.  If omitted, [4mgroff[24m’s [1m-l [22mand [1m-L[0m
              options are ignored.

       [1mres [4m[22mn[24m  The device resolution is [4mn[24m basic units per inch.

       [1msizes [4m[22ms1[24m ... [4msn[24m [1m0[0m
              The device has fonts at [4ms1[24m, ..., [4msn[24m scaled points  (see  below).
              The  list  of sizes must be terminated by a [1m0[22m.  Each [4msi[24m can also
              be a range of sizes [4mm[24m–[4mn[24m.  The list can extend over more than one
              line.

       [1msizescale [4m[22mn[0m
              A typographical point is subdivided into [4mn[24m scaled  points.   The
              default is [1m1[22m.

       [1mstyles [4m[22mS1[24m ... [4mSm[0m
              The  first  [4mm[24m font mounting positions are associated with styles
              [4mS1[24m, ..., [4mSm[24m.

       [1mtcommand[0m
              The postprocessor can handle the [1mt  [22mand  [1mu  [22mintermediate  output
              commands.

       [1municode[0m
              The  output  device  supports  the  complete Unicode repertoire.
              This directive is useful only for devices which produce  charac‐
              ter entities instead of glyphs.

              If  [1municode  [22mis  present,  no [1mcharset [22msection is required in the
              font description files since the  Unicode  handling  built  into
              [4mgroff[24m is used.  However, if there are entries in a font descrip‐
              tion  file’s  [1mcharset  [22msection, they either override the default
              mappings for those particular characters  or  add  new  mappings
              (normally for composite characters).

              The [1mutf8[22m, [1mhtml[22m, and [1mxhtml [22moutput devices use this directive.

       [1munitwidth [4m[22mn[0m
              Quantities  in the font description files are in basic units for
              fonts whose type size is [4mn[24m scaled points.

       [1munscaled_charwidths[0m
              Make the font  handling  module  always  return  unscaled  glyph
              widths.  The [4mgrohtml[24m driver uses this directive.

       [1muse_charnames_in_special[0m
              [4mtroff[24m should encode named glyphs inside device control commands.
              The [4mgrohtml[24m driver uses this directive.

       [1mvert [4m[22mn[24m The  vertical motion quantum is [4mn[24m basic units.  Vertical quanti‐
              ties are rounded to multiples of [4mn.[0m

       [1mcharset[0m
              This directive and the rest of the file are ignored.  It is rec‐
              ognized for compatibility with other [4mtroff[24m implementations.   In
              GNU  [4mtroff[24m,  character set repertoire is described on a per‐font
              basis.

       [4mtroff[24m  recognizes  but  ignores  the  directives  [1mspare1[22m,  [1mspare2[22m,  and
       [1mbiggestfont[22m.

       The  [1mres[22m,  [1munitwidth[22m, [1mfonts[22m, and [1msizes [22mlines are mandatory.  Directives
       not listed above are ignored by [4mtroff[24m but may be used by postprocessors
       to obtain further information about the device.

[1mFont description file format[0m
       On typesetting output devices, each font is typically available at mul‐
       tiple sizes.  While paper measurements in the device  description  file
       are in absolute units, measurements applicable to fonts must be propor‐
       tional  to  the type size.  [4mgroff[24m achieves this using the precedent set
       by AT&T device‐independent [4mtroff[24m: one font size is chosen  as  a  norm,
       and  all  others are scaled linearly relative to that basis.  The “unit
       width” is the number of basic units per point when the font is rendered
       at this nominal size.

       For instance, [4mgroff[24m’s [1mlbp [22mdevice uses a [1munitwidth [22mof  800.   Its  Times
       roman  font  (“[1mTR[22m”)  has a [1mspacewidth [22mof 833; this is also the width of
       its comma, period, centered period, and  mathematical  asterisk,  while
       its  “M” is 2,963 basic units.  Thus, an “M” on the [1mlbp [22mdevice is 2,963
       basic units wide at a notional type size  of  800  points.   (800‐point
       type is not practical for most purposes, but using it enables the quan‐
       tities in the font description files to be expressed as integers.)

       A  font  description file has two sections.  The first is a sequence of
       directives, and is parsed similarly to the [4mDESC[24m file  described  above.
       Except for the directive names that begin the second section, their or‐
       dering  is immaterial.  Later directives of the same name override ear‐
       lier ones, spaces and tabs are handled in the same way,  and  the  same
       comment syntax is supported.  Empty lines are ignored throughout.

       [1mname [4m[22mF[24m The  name  of  the  font  is [4mF[24m.  “[1mDESC[22m” is an invalid font name.
              Simple integers are valid, but their use is discouraged.  ([4mgroff[0m
              requests and escape sequences interpret non‐negative font  names
              as mounting positions instead.  Further, a font named “[1m0[22m” cannot
              be automatically mounted by the [1mfonts [22mdirective of a [4mDESC[24m file.)

       [1mspacewidth [4m[22mn[0m
              The width of an unadjusted inter‐word space is [4mn[24m basic units.

       The  directives above must appear in the first section; those below are
       optional.

       [1mslant [4m[22mn[0m
              The font’s glyphs have a slant of [4mn[24m degrees; a positive [4mn[24m slants
              in the direction of text flow.

       [1mligatures [4m[22mlig1[24m ... [4mlign[24m [[1m0[22m]
              Glyphs [4mlig1[24m, ..., [4mlign[24m are ligatures; possible ligatures are [1mff[22m,
              [1mfi[22m, [1mfl[22m, [1mffi[22m, and [1mffl[22m.  For compatibility with other [4mtroff[24m imple‐
              mentations, the list of ligatures may be terminated  with  a  [1m0[22m.
              The list of ligatures must not extend over more than one line.

       [1mspecial[0m
              The  font  is  [4mspecial[24m:  when  a  glyph is requested that is not
              present in the current font, it is sought in any  mounted  fonts
              that bear this property.

       Other  directives in this section are ignored by [4mtroff[24m, but may be used
       by postprocessors to obtain further information about the font.

       The second section contains one or two subsections.  These  can  appear
       in  either  order;  the first one encountered commences the second sec‐
       tion.  Each starts with a directive on a line  by  itself.   A  [1mcharset[0m
       subsection  is  mandatory  unless the associated [4mDESC[24m file contains the
       [1municode [22mdirective.  Another subsection, [1mkernpairs[22m, is optional.

       The directive [1mcharset [22mstarts the character set subsection.  (For  type‐
       setter  devices,  this  directive is misnamed since it starts a list of
       glyphs, not characters.)  It precedes a series of  glyph  descriptions,
       one  per  line.   Each such glyph description comprises a set of fields
       separated by spaces or tabs and organized as follows.

              [4mname[24m [4mmetrics[24m [4mtype[24m [4mcode[24m [[4mentity‐name[24m] [[1m-- [4m[22mcomment[24m]

       [4mname[24m identifies the glyph: if [4mname[24m is a printable character [4mc[24m, it  cor‐
       responds to the [4mtroff[24m ordinary character [4mc[24m.  If [4mname[24m is a multi‐charac‐
       ter sequence not beginning with [1m\[22m, it corresponds to the GNU [4mtroff[24m spe‐
       cial  character  escape sequence “[1m\[[4m[22mname[24m[1m][22m”.  A name consisting of three
       minus signs, “[1m---[22m”, indicates that the glyph is  unnamed:  such  glyphs
       can  be  accessed  only  by the [1m\N [22mescape sequence in [4mtroff[24m.  A special
       character named “[1m---[22m” can still be defined using [1m.char [22mand similar  re‐
       quests.  The [4mname[24m “[1m\-[22m” defines the minus sign glyph.  Finally, [4mname[24m can
       be the horizontal motion escape sequences, [1m\| [22mand [1m\^ [22m(“thin” and “hair”
       spaces,  respectively),  in  which case only the width metric described
       below is applied; a font can thus customize the widths of these spaces.

       The form of the [4mmetrics[24m field is as follows (on one  line;  it  may  be
       broken here for readability).

              [4mwidth[24m[[1m,[22m[[4mheight[24m[[1m,[22m[[4mdepth[24m[[1m,[22m[[4mitalic‐correction[24m[[1m,[22m[
              [4mleft‐italic‐correction[24m[[1m,[22m[[4msubscript‐correction[24m]]]]]]]]]]

       There  must  not  be  any  spaces, tabs, or newlines between these [4msub‐[0m
       [4mfields,[24m which are in basic units expressed as  decimal  integers.   Un‐
       specified  subfields default to [1m0[22m.  Since there is no associated binary
       format, these values are not required to fit into the C  language  data
       type [1mchar [22mas they are in AT&T device‐independent [4mtroff[24m.

       The  [4mwidth[24m  subfield gives the width of the glyph.  The [4mheight[24m subfield
       gives the height of the glyph (upwards is positive); if  a  glyph  does
       not extend above the baseline, it should be given a zero height, rather
       than  a  negative  height.   The  [4mdepth[24m subfield gives the depth of the
       glyph, that is, the distance below the baseline to which the glyph  ex‐
       tends  (downwards  is  positive);  if a glyph does not extend below the
       baseline, it should be given a  zero  depth,  rather  than  a  negative
       depth.   Italic corrections are relevant to glyphs in italic or oblique
       styles.  The [4mitalic‐correction[24m is the amount of space  that  should  be
       added  after  an oblique glyph to be followed immediately by an upright
       glyph.  The [4mleft‐italic‐correction[24m is the amount of space  that  should
       be  added  before an oblique glyph to be preceded immediately by an up‐
       right glyph.  The [4msubscript‐correction[24m is  the  amount  of  space  that
       should  be  added after an oblique glyph to be followed by a subscript;
       it should be less than the italic correction.

       For fonts used with typesetting devices, the [4mtype[24m field gives  a  feat‐
       ural  description  of the glyph: it is a bit mask recording whether the
       glyph is an ascender, descender, both, or neither.  When  a  [1m\w  [22mescape
       sequence  is  interpolated, these values are bitwise or‐ed together for
       each glyph and stored in the [1mct [22mregister.   In  font  descriptions  for
       terminal  devices,  all glyphs might have a type of zero, regardless of
       their appearance.

       0      means the glyph lies entirely between the baseline and  a  hori‐
              zontal line at the “x‐height” of the font, as with “a”, “c”, and
              “x”;

       1      means the glyph descends below the baseline, like “p”;

       2      means  the  glyph ascends above the font’s x‐height, like “A” or
              “b”); and

       3      means the glyph is both an ascender and a descender—this is true
              of parentheses in some fonts.

       The [4mcode[24m field gives a numeric identifier that the  postprocessor  uses
       to  render  the  glyph.  The glyph can be specified to [4mtroff[24m using this
       code by means of the [1m\N [22mescape sequence.  The code can be  any  integer
       (that  is,  any  integer parsable by the C standard library’s [4mstrtol[24m(3)
       function).

       The [4mentity‐name[24m field defines an identifier  for  the  glyph  that  the
       postprocessor  uses  to  print the [4mtroff[24m glyph [4mname[24m.  This field is op‐
       tional; it was introduced so that the [4mgrohtml[24m output driver  could  en‐
       code its character set.  For example, the glyph [1m\[Po] [22mis represented by
       “[1m&pound;[22m” in HTML 4.0.  For efficiency, these data are now compiled di‐
       rectly into [4mgrohtml[24m.  [4mgrops[24m uses the field to build sub‐encoding arrays
       for  PostScript fonts containing more than 256 glyphs.  Anything on the
       line after the [4mentity‐name[24m field or “[1m--[22m” is ignored.

       A line in the [1mcharset [22msection can also have the form
              [4mname[24m [1m"[0m
       identifying [4mname[24m as another name for the glyph mentioned in the preced‐
       ing line.  Such aliases can be chained.

       The directive [1mkernpairs [22mstarts a list of kerning adjustments to be made
       to adjacent glyph pairs from this font.   It  contains  a  sequence  of
       lines formatted as follows.
              [4mg1[24m [4mg2[24m [4mn[0m
       The  foregoing  means  that when glyph [4mg1[24m is typeset immediately before
       [4mg2[24m, the space between them should be  increased  by  [4mn[24m.   Most  kerning
       pairs should have a negative value for [4mn[24m.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/dev[24mname[4m/DESC[0m
              describes the output device [4mname[24m.

       [4m/usr/share/groff/1.23.0/font/dev[24mname[4m/[24mF
              describes the font known as [4mF[24m on device [4mname[24m.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       “Troff  User’s  Manual” by Joseph F. Ossanna, 1976 (revised by Brian W.
       Kernighan, 1992), AT&T Bell Laboratories  Computing  Science  Technical
       Report No. 54, widely called simply “CSTR #54”, documents the language,
       device and font description file formats, and device‐independent output
       format referred to collectively in [4mgroff[24m documentation as “AT&T [4mtroff[24m”.

       “A Typesetter‐independent TROFF” by Brian W. Kernighan, 1982, AT&T Bell
       Laboratories  Computing Science Technical Report No. 97, provides addi‐
       tional insights into the device and font description file  formats  and
       device‐independent output format.

       [4mgroff[24m(1), subsection “Utilities”, lists programs available for describ‐
       ing  fonts  in  a variety of formats such that [4mgroff[24m output drivers can
       use them.

       [4mtroff[24m(1) documents the default device and font description file  search
       path.

       [4mgroff_out[24m(5), [4maddftinfo[24m(1)

groff 1.23.0                      5 July 2023                    [4mgroff_font[24m(5)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_out[24m(5)                  File Formats Manual                 [4mgroff_out[24m(5)

[1mName[0m
       groff_out - GNU [4mroff[24m intermediate output format

[1mDescription[0m
       The  fundamental operation of the [4mtroff[24m(1) formatter is the translation
       of the [4mgroff[24m(7) input language into a series of instructions  concerned
       primarily  with  placing  glyphs or geometric objects at specific posi‐
       tions on a rectangular page.  In the  following  discussion,  the  term
       [4mcommand[24m  refers  to  this  intermediate  output  language, never to the
       [4mgroff[24m(7) language intended for use by document  authors.   Intermediate
       output commands comprise several categories: glyph output; font, color,
       and text size selection; motion of the printing position; page advance‐
       ment;  drawing  of geometric primitives; and device control commands, a
       catch‐all for other operations.  The last includes directives to  start
       and stop output, identify the intended output device, and embed URL hy‐
       perlinks in supported output formats.

       Because  the front‐end command [4mgroff[24m(1) is a wrapper that normally runs
       the [4mtroff[24m formatter to generate intermediate output and an output  dri‐
       ver  (“postprocessor”)  to  consume it, users normally do not encounter
       this language.  The [4mgroff[24m program’s [1m-Z [22moption  inhibits  postprocessing
       such  that  this  intermediate  output  is  sent to the standard output
       stream as when [4mtroff[24m is run manually.

       [4mgroff[24m’s intermediate output facilitates the development of output  dri‐
       vers  and  other postprocessors by offering a common programming inter‐
       face.  It is an extension of the page description language developed by
       Brian Kernighan for AT&T device‐independent [4mtroff[24m circa 1980.  Where  a
       distinction  is  necessary,  we will say “[4mtroff[24m output” to describe the
       output of GNU [4mtroff[24m, and “intermediate output” to denote  the  language
       accepted by the parser implemented in [4mgroff[24m’s internal C++ library used
       by most of its output drivers.

[1mLanguage concepts[0m
       During the run of [4mtroff[24m, the [4mroff[24m input is cracked down to the informa‐
       tion on what has to be printed at what position on the intended device.
       So  the  language of the [4mintermediate[24m [4moutput[24m format can be quite small.
       Its only elements are commands with or without arguments.  In this doc‐
       ument, the term “command” always refers to the [4mintermediate[24m [4moutput[24m lan‐
       guage, never to the [4mroff[24m language used for document formatting.   There
       are commands for positioning and text writing, for drawing, and for de‐
       vice controlling.

   [1mSeparation[0m
       [4mClassical[24m  [4mtroff[24m  [4moutput[24m  had  strange requirements on whitespace.  The
       [4mgroff[24m output parser, however, is smart about whitespace  by  making  it
       maximally  optional.   The whitespace characters, i.e., the [4mtab[24m, [4mspace[24m,
       and [4mnewline[24m characters, always have a syntactical  meaning.   They  are
       never printable because spacing within the output is always done by po‐
       sitioning commands.

       Any  sequence of [4mspace[24m or [4mtab[24m characters is treated as a single [4msyntac‐[0m
       [4mtical[24m [4mspace[24m.  It separates commands and arguments, but is only required
       when there would occur a clashing between the command code and the  ar‐
       guments  without  the  space.   Most  often, this happens when variable
       length command names, arguments, argument lists,  or  command  clusters
       meet.   Commands  and  arguments with a known, fixed length need not be
       separated by [4msyntactical[24m [4mspace[24m.

       A line break is a syntactical element, too.  Every command argument can
       be followed by whitespace, a comment, or a newline character.   Thus  a
       [4msyntactical[24m  [4mline[24m  [4mbreak[24m  is defined to consist of optional [4msyntactical[0m
       [4mspace[24m that is optionally followed by a comment, and a  newline  charac‐
       ter.

       The  normal commands, those for positioning and text, consist of a sin‐
       gle letter taking a fixed number of arguments.  For historical reasons,
       the parser allows stacking of such commands on the same line, but  for‐
       tunately, in [4mgroff[24m [4mintermediate[24m [4moutput[24m, every command with at least one
       argument  is  followed  by a line break, thus providing excellent read‐
       ability.

       The other commands — those for drawing and device controlling — have  a
       more complicated structure; some recognize long command names, and some
       take  a variable number of arguments.  So all [1mD [22mand [1mx [22mcommands were de‐
       signed to request a [4msyntactical[24m [4mline[24m [4mbreak[24m after their  last  argument.
       Only  one  command, ‘[1mx X[22m’ has an argument that can stretch over several
       lines, all other commands must have all of their arguments on the  same
       line  as  the  command,  i.e., the arguments may not be split by a line
       break.

       Lines containing only spaces and/or a comment are treated as empty  and
       ignored.

   [1mArgument units[0m
       Some commands accept integer arguments that represent measurements, but
       the  scaling  units  of  the formatter’s language are never used.  Most
       commands assume a scaling unit of “[1mu[22m” (basic units), and others use “[1mz[22m”
       (scaled points); These are defined by the parameters specified  in  the
       device’s  [4mDESC[24m  file; see [4mgroff_font[24m(5) and, for more on scaling units,
       [4mgroff[24m(7) and [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, the [4mgroff[24m  Texinfo
       manual.  Color‐related commands use dimensionless integers.

       Note  that  single  characters  can have the eighth bit set, as can the
       names of fonts and special characters (this is, glyphs).  The names  of
       glyphs  and  fonts  can  be of arbitrary length.  A glyph that is to be
       printed will always be in the current font.

       A string argument is always terminated by the next whitespace character
       (space, tab, or newline); an embedded [1m# [22mcharacter is regarded  as  part
       of the argument, not as the beginning of a comment command.  An integer
       argument  is  already terminated by the next non‐digit character, which
       then is regarded as the first character of the next  argument  or  com‐
       mand.

   [1mDocument parts[0m
       A  correct [4mintermediate[24m [4moutput[24m document consists of two parts, the [4mpro‐[0m
       [4mlogue[24m and the [4mbody[24m.

       The task of the [4mprologue[24m is to set the general device parameters  using
       three  exactly specified commands.  The [4mgroff[24m [4mprologue[24m is guaranteed to
       consist of the following three lines (in that order):

              [1mx T [4m[22mdevice[0m
              [1mx res [4m[22mn[24m [4mh[24m [4mv[0m
              [1mx init[0m

       with the arguments set as outlined in subsection “Device  Control  Com‐
       mands”  below.   However, the parser for the [4mintermediate[24m [4moutput[24m format
       is able to swallow additional whitespace and comments as well.

       The [4mbody[24m is the main section for processing the document data.  Syntac‐
       tically, it is a sequence of any commands different from the ones  used
       in  the [4mprologue[24m.  Processing is terminated as soon as the first [1mx stop[0m
       command is encountered; the last line of any [4mgroff[24m [4mintermediate[24m  [4moutput[0m
       always contains such a command.

       Semantically,  the  [4mbody[24m  is page oriented.  A new page is started by a
       [1mp [22mcommand.  Positioning, writing, and drawing commands are always  done
       within  the  current page, so they cannot occur before the first [1mp [22mcom‐
       mand.  Absolute positioning (by the [1mH [22mand [1mV [22mcommands) is done  relative
       to the current page, all other positioning is done relative to the cur‐
       rent location within this page.

[1mCommand reference[0m
       This  section describes all [4mintermediate[24m [4moutput[24m commands, the classical
       commands as well as the [4mgroff[24m extensions.

   [1mComment command[0m
       [1m#[4m[22manything[24m⟨line‐break⟩
              A comment.  Ignore any characters from the [1m# [22mcharacter up to the
              next newline.  Each comment can be preceded by arbitrary [4msyntac‐[0m
              [4mtical[24m [4mspace[24m; every command can be terminated by a comment.

   [1mSimple commands[0m
       The commands in this subsection have a command  code  consisting  of  a
       single character, taking a fixed number of arguments.  Most of them are
       commands  for  positioning  and text writing.  These commands are smart
       about whitespace.  Optionally, [4msyntactical[24m [4mspace[24m can  be  inserted  be‐
       fore,  after, and between the command letter and its arguments.  All of
       these commands are stackable, i.e., they can be preceded by other  sim‐
       ple  commands or followed by arbitrary other commands on the same line.
       A separating [4msyntactical[24m [4mspace[24m is necessary only when two integer argu‐
       ments would clash or if the preceding argument ends with a string argu‐
       ment.

       [1mC [4m[22mid[24m⟨white‐space⟩
              Typeset the glyph of the special character [4mid[24m.  Trailing syntac‐
              tical space is necessary to allow special character names of ar‐
              bitrary length.  The drawing position is not advanced.

       [1mc [4m[22mc[24m    Typeset the glyph of the ordinary character  character  [4mc[24m.   The
              drawing position is not advanced.

       [1mf [4m[22mn[24m    Select the font mounted at position [4mn[24m.  [4mn[24m cannot be negative.

       [1mH [4m[22mn[24m    Horizontally move the drawing position to [4mn[24m basic units from the
              left edge of the page.  [4mn[24m cannot be negative.

       [1mh [4m[22mn[24m    Move  the  drawing position right [4mn[24m basic units.  AT&T [4mtroff[24m al‐
              lowed negative [4mn;[24m GNU [4mtroff[24m does not produce  such  values,  but
              [4mgroff[24m’s output driver library handles them.

       [1mm [4m[22mscheme[24m [[4mcomponent[24m ...]
              Select  the stroke color using the [4mcomponent[24ms in the color space
              [4mscheme[24m.  Each [4mcomponent[24m is an integer between 0 and 65536.   The
              quantity of components and their meanings vary with each [4mscheme[24m.
              This command is a [4mgroff[24m extension.

              [1mmc [4m[22mcyan[24m [4mmagenta[24m [4myellow[0m
                     Use  the  CMY color scheme with components cyan, magenta,
                     and yellow.

              [1mmd     [22mUse the default  color  (no  components;  black  in  most
                     cases).

              [1mmg [4m[22mgray[0m
                     Use a grayscale color scheme with a component ranging be‐
                     tween 0 (black) and 65536 (white).

              [1mmk [4m[22mcyan[24m [4mmagenta[24m [4myellow[24m [4mblack[0m
                     Use  the CMYK color scheme with components cyan, magenta,
                     yellow, and black.

              [1mmr [4m[22mred[24m [4mgreen[24m [4mblue[0m
                     Use the RGB color scheme with components red, green,  and
                     blue.

       [1mN [4m[22mn[24m    Typeset  the  glyph with index [4mn[24m in the current font.  [4mn[24m is nor‐
              mally a non‐negative integer.  The drawing position is  not  ad‐
              vanced.   The [1mhtml [22mand [1mxhtml [22mdevices use this command with nega‐
              tive [4mn[24m to produce unbreakable space; the absolute value of [4mn[24m  is
              taken and interpreted in basic units.

       [1mn [4m[22mb[24m [4ma[24m  Indicate  a  break.   No  action  is  performed;  the command is
              present to make the output more easily parsed.  The  integers  [4mb[0m
              and  [4ma[24m  describe the vertical space amounts before and after the
              break, respectively.  GNU [4mtroff[24m issues this command but  [4mgroff[24m’s
              output driver library ignores it.  See [1mv [22mand [1mV[22m.

       [1mp [4m[22mn[24m    Begin  a  new page, setting its number to [4mn[24m.  Each page is inde‐
              pendent, even from those using the same  number.   The  vertical
              drawing  position  is  set  to 0.  All positioning, writing, and
              drawing commands are interpreted in the context of a page, so  a
              [1mp [22mcommand must precede them.

       [1ms [4m[22mn[24m    Set  type  size  to [4mn[24m scaled points (unit [1mz [22min GNU [4mtroff[24m).  AT&T
              [4mtroff[24m used unscaled points ([1mp[22m) instead; see section “Compatibil‐
              ity” below.

       [1mt [4m[22mxyz[24m...⟨white‐space⟩
       [1mt [4m[22mxyz[24m... [4mdummy‐arg[24m⟨white‐space⟩
              Typeset word [4mxyz[24m; that is, set a  sequence  of  ordinary  glyphs
              named  [4mx[24m,  [4my[24m,  [4mz[24m,  ..., terminated by a space or newline; an op‐
              tional second integer argument is ignored (this allows the  for‐
              matter  to generate an even number of arguments).  Each glyph is
              set at the current drawing position, and the  position  is  then
              advanced  horizontally by the glyph’s width.  A glyph’s width is
              read from its metrics in the font description  file,  scaled  to
              the current type size, and rounded to a multiple of the horizon‐
              tal motion quantum.  Use the [1mC [22mcommand to emplace glyphs of spe‐
              cial characters.  The [1mt [22mcommand is a [4mgroff[24m extension and is out‐
              put  only  for devices whose [4mDESC[24m file contains the [1mtcommand [22mdi‐
              rective; see [4mgroff_font[24m(5).

       [1mu [4m[22mn[24m [4mxyz[24m...
       [1mu [4m[22mxyz[24m... [4mdummy‐arg[24m⟨white‐space⟩
              Typeset word [4mxyz[24m with track kerning.  As [1mt[22m,  but  after  placing
              each  glyph,  the  drawing position is further advanced horizon‐
              tally by [4mn[24m basic units.  The [1mu [22mcommand is a [4mgroff[24m extension  and
              is output only for devices whose [4mDESC[24m file contains the [1mtcommand[0m
              directive; see [4mgroff_font[24m(5).

       [1mV [4m[22mn[24m    Vertically  move  the drawing position to [4mn[24m basic units from the
              top edge of the page.  [4mn[24m cannot be negative.

       [1mv [4m[22mn[24m    Move the drawing position down [4mn[24m basic units.   AT&T  [4mtroff[24m  al‐
              lowed  negative  [4mn;[24m  GNU [4mtroff[24m does not produce such values, but
              [4mgroff[24m’s output driver library handles them.

       [1mw      [22mIndicate an inter‐word space.  No action is performed; the  com‐
              mand is present to make the output more easily parsed.  Only ad‐
              justable,  breakable inter‐word spaces are thus described; those
              resulting from [1m\~ [22mor horizontal motion escape sequences are not.
              GNU [4mtroff[24m issues this command but [4mgroff[24m’s output driver  library
              ignores it.  See [1mh [22mand [1mH[22m.

   [1mGraphics commands[0m
       Each graphics or drawing command in the [4mintermediate[24m [4moutput[24m starts with
       the  letter  [1mD [22mfollowed by one or two characters that specify a subcom‐
       mand; this is followed by a fixed or variable number of  integer  argu‐
       ments  that are separated by a single space character.  A [1mD [22mcommand may
       not be followed by another command on the same line (apart from a  com‐
       ment), so each [1mD [22mcommand is terminated by a [4msyntactical[24m [4mline[24m [4mbreak[24m.

       [4mtroff[24m output follows the classical spacing rules (no space between com‐
       mand and subcommand, all arguments are preceded by a single space char‐
       acter),  but  the parser allows optional space between the command let‐
       ters and makes the space before the first argument optional.  As usual,
       each space can be any sequence of tab and space characters.

       Some graphics commands can take a variable  number  of  arguments.   In
       this  case,  they  are  integers  representing a size measured in basic
       units [1mu[22m.  The [4mh[24m arguments stand for horizontal distances where positive
       means right, negative left.  The [4mv[24m arguments stand  for  vertical  dis‐
       tances where positive means down, negative up.  All these distances are
       offsets relative to the current location.

       Unless  indicated otherwise, each graphics command directly corresponds
       to a similar [4mgroff[24m [1m\D [22mescape sequence; see [4mgroff[24m(7).

       Unknown [1mD [22mcommands are assumed to be  device‐specific.   Its  arguments
       are  parsed as strings; the whole information is then sent to the post‐
       processor.

       In the following command reference,  the  syntax  element  [4m⟨line‐break⟩[0m
       means  a  [4msyntactical[24m  [4mline[24m [4mbreak[24m as defined in subsection “Separation”
       above.

       [1mD~ [4m[22mh1[24m [4mv1[24m [4mh2[24m [4mv2[24m ... [4mhn[24m [4mvn[24m⟨line‐break⟩
              Draw B‐spline from current position to offset ([4mh1[24m, [4mv1[24m), then  to
              offset  ([4mh2[24m, [4mv2[24m)  if  given,  etc., up to ([4mhn[24m, [4mvn[24m). This command
              takes a variable number of argument pairs; the current  position
              is moved to the terminal point of the drawn curve.

       [1mDa [4m[22mh1[24m [4mv1[24m [4mh2[24m [4mv2[24m⟨line‐break⟩
              Draw  arc from current position to ([4mh1[24m, [4mv1[24m)+([4mh2[24m, [4mv2[24m) with center
              at ([4mh1[24m, [4mv1[24m); then move the current position to the  final  point
              of the arc.

       [1mDC [4m[22md[24m⟨line‐break⟩
       [1mDC [4m[22md[24m [4mdummy‐arg[24m⟨line‐break⟩
              Draw a solid circle using the current fill color with diameter [4md[0m
              (integer  in  basic  units [1mu[22m) with leftmost point at the current
              position; then move the current position to the rightmost  point
              of  the  circle.  An optional second integer argument is ignored
              (this allows the formatter to generate an even number  of  argu‐
              ments).  This command is a [4mgroff[24m extension.

       [1mDc [4m[22md[24m⟨line‐break⟩
              Draw circle line with diameter [4md[24m (integer in basic units [1mu[22m) with
              leftmost  point  at  the current position; then move the current
              position to the rightmost point of the circle.

       [1mDE [4m[22mh[24m [4mv[24m⟨line‐break⟩
              Draw a solid ellipse in the current fill color with a horizontal
              diameter of [4mh[24m and a vertical diameter of [4mv[24m (both integers in ba‐
              sic units [1mu[22m) with the leftmost point at  the  current  position;
              then  move  to the rightmost point of the ellipse.  This command
              is a [4mgroff[24m extension.

       [1mDe [4m[22mh[24m [4mv[24m⟨line‐break⟩
              Draw an outlined ellipse with a horizontal diameter of [4mh[24m  and  a
              vertical diameter of [4mv[24m (both integers in basic units [1mu[22m) with the
              leftmost  point  at current position; then move to the rightmost
              point of the ellipse.

       [1mDF [4m[22mcolor‐scheme[24m [[4mcomponent[24m ...]⟨line‐break⟩
              Set fill color for solid drawing objects using  different  color
              schemes;  the  analogous  command for setting the color of text,
              line graphics, and the outline of graphic  objects  is  [1mm[22m.   The
              color  components  are  specified as integer arguments between 0
              and 65536.  The number of color  components  and  their  meaning
              vary for the different color schemes.  These commands are gener‐
              ated  by  the  [4mgroff[24m escape sequences [1m\D'F [22m...[1m’  [22mand [1m\M [22m(with no
              other corresponding graphics commands).  This command is a [4mgroff[0m
              extension.

              [1mDFc [4m[22mcyan[24m [4mmagenta[24m [4myellow[24m⟨line‐break⟩
                     Set fill color for solid drawing objects  using  the  CMY
                     color  scheme,  having  the  3 color components cyan, ma‐
                     genta, and yellow.

              [1mDFd [22m⟨line‐break⟩
                     Set fill color for solid drawing objects to  the  default
                     fill color value (black in most cases).  No component ar‐
                     guments.

              [1mDFg [4m[22mgray[24m⟨line‐break⟩
                     Set  fill color for solid drawing objects to the shade of
                     gray given by the argument, an integer between 0  (black)
                     and 65536 (white).

              [1mDFk [4m[22mcyan[24m [4mmagenta[24m [4myellow[24m [4mblack[24m⟨line‐break⟩
                     Set  fill  color for solid drawing objects using the CMYK
                     color scheme, having the 4  color  components  cyan,  ma‐
                     genta, yellow, and black.

              [1mDFr [4m[22mred[24m [4mgreen[24m [4mblue[24m⟨line‐break⟩
                     Set  fill  color  for solid drawing objects using the RGB
                     color scheme, having the 3 color components  red,  green,
                     and blue.

       [1mDf [4m[22mn[24m⟨line‐break⟩
              The argument [4mn[24m must be an integer in the range -32767 to 32767.

              0≤[4mn[24m≤1000
                     Set  the  color  for  filling  solid drawing objects to a
                     shade of gray, where 0 corresponds to solid  white,  1000
                     (the  default)  to  solid black, and values in between to
                     intermediate shades of gray; this is obsoleted by command
                     [1mDFg[22m.

              [4mn[24m<0 or [4mn[24m>1000
                     Set the filling color to the color that is currently  be‐
                     ing  used  for  the  text and the outline, see command [1mm[22m.
                     For example, the command sequence

                            mg 0 0 65536
                            Df -1

                     sets all colors to blue.

              This command is a [4mgroff[24m extension.

       [1mDl [4m[22mh[24m [4mv[24m⟨line‐break⟩
              Draw line from current position to offset  ([4mh[24m, [4mv[24m)  (integers  in
              basic  units  [1mu[22m);  then  set  current position to the end of the
              drawn line.

       [1mDp [4m[22mh1[24m [4mv1[24m [4mh2[24m [4mv2[24m ... [4mhn[24m [4mvn[24m⟨line‐break⟩
              Draw a polygon line from current position  to  offset  ([4mh1[24m, [4mv1[24m),
              from  there to offset ([4mh2[24m, [4mv2[24m), etc., up to offset ([4mhn[24m, [4mvn[24m), and
              from there back to the starting position.  For  historical  rea‐
              sons, the position is changed by adding the sum of all arguments
              with  odd  index to the current horizontal position and the even
              ones to the vertical position.  Although this doesn’t make sense
              it is kept for compatibility.  This command is  a  [4mgroff[24m  exten‐
              sion.

       [1mDP [4m[22mh1[24m [4mv1[24m [4mh2[24m [4mv2[24m ... [4mhn[24m [4mvn[24m⟨line‐break⟩
              The same macro as the corresponding [1mDp [22mcommand with the same ar‐
              guments,  but  draws  a  solid polygon in the current fill color
              rather than an outlined polygon.  The position is changed in the
              same way as with [1mDp[22m.  This command is a [4mgroff[24m extension.

       [1mDt [4m[22mn[24m⟨line‐break⟩
              Set the current  line  thickness  to  [4mn[24m  (an  integer  in  basic
              units  [1mu[22m)  if  [4mn[24m>0;  if  [4mn[24m=0  select the smallest available line
              thickness; otherwise, the line thickness is made proportional to
              the type size, which is the default.   For  historical  reasons,
              the horizontal position is changed by adding the argument to the
              current  horizontal position, while the vertical position is not
              changed.  Although this doesn’t make sense, it is kept for  com‐
              patibility.  This command is a [4mgroff[24m extension.

   [1mDevice control commands[0m
       Each  device  control  command  starts  with the letter [1mx [22mfollowed by a
       space character (optional or arbitrary space/tab in [4mgroff[24m) and  a  sub‐
       command  letter  or  word; each argument (if any) must be preceded by a
       [4msyntactical[24m [4mspace[24m.  All [1mx [22mcommands are terminated by a [4msyntactical[24m [4mline[0m
       [4mbreak[24m; no device control command can be followed by another command  on
       the same line (except a comment).

       The  subcommand is basically a single letter, but to increase readabil‐
       ity, it can be written as a word, i.e., an arbitrary sequence of  char‐
       acters  terminated  by  the next tab, space, or newline character.  All
       characters of the subcommand word but the  first  are  simply  ignored.
       For example, [4mtroff[24m outputs the initialization command [1mx i [22mas [1mx init [22mand
       the  resolution command [1mx r [22mas [1mx res[22m.  But writings like [1mx i_like_groff[0m
       and [1mx roff_is_groff [22mare accepted as well to mean the same commands.

       In the following, the syntax element [4m⟨line‐break⟩[24m means  a  [4msyntactical[0m
       [4mline[24m [4mbreak[24m as defined in subsection “Separation” above.

       [1mxF [4m[22mname[24m⟨line‐break⟩
              ([4mFilename[24m control command)
              Use  [4mname[24m as the intended name for the current file in error re‐
              ports.  This is useful for remembering the  original  file  name
              when [4mgroff[24m uses an internal piping mechanism.  The input file is
              not changed by this command.  This command is a [4mgroff[24m extension.

       [1mxf [4m[22mn[24m [4ms[24m⟨line‐break⟩
              ([4mfont[24m control command)
              Mount font position [4mn[24m (a non‐negative integer) with font named [4ms[0m
              (a text word); see [4mgroff_font[24m(5).

       [1mxH [4m[22mn[24m⟨line‐break⟩
              ([4mHeight[24m control command)
              Set  character  height  to  [4mn[24m  (a  positive  integer  in  scaled
              points [1mz[22m).  [4mClassical[24m [4mtroff[24m used the unit  points  ([1mp[22m)  instead;
              see section “Compatibility” below.

       [1mxi [22m⟨line‐break⟩
              ([4minit[24m control command)
              Initialize device.  This is the third command of the [4mprologue[24m.

       [1mxp [22m⟨line‐break⟩
              ([4mpause[24m control command)
              Parsed but ignored.  The classical documentation reads [4mpause[24m [4mde‐[0m
              [4mvice,[24m [4mcan[24m [4mbe[24m [4mrestarted[24m.

       [1mxr [4m[22mn[24m [4mh[24m [4mv[24m⟨line‐break⟩
              ([4mresolution[24m control command)
              Resolution is [4mn[24m, while [4mh[24m is the minimal horizontal motion, and [4mv[0m
              the minimal vertical motion possible with this device; all argu‐
              ments  are positive integers in basic units [1mu [22mper inch.  This is
              the second command of the [4mprologue[24m.

       [1mxS [4m[22mn[24m⟨line‐break⟩
              ([4mSlant[24m control command)
              Set slant to [4mn[24m degrees (an integer in basic units [1mu[22m).

       [1mxs [22m⟨line‐break⟩
              ([4mstop[24m control command)
              Terminates the processing of the current  file;  issued  as  the
              last command of any [4mintermediate[24m [4mtroff[24m [4moutput[24m.

       [1mxt [22m⟨line‐break⟩
              ([4mtrailer[24m control command)
              Generate  trailer  information,  if any.  In [1mgroff[22m, this is cur‐
              rently ignored.

       [1mxT [4m[22mxxx[24m⟨line‐break⟩
              ([4mTypesetter[24m control command)
              Set the name of the output driver to [4mxxx[24m,  a  sequence  of  non‐
              whitespace  characters  terminated  by whitespace.  The possible
              names correspond to those of [4mgroff[24m’s [1m-T  [22moption.   This  is  the
              first command of the prologue.

       [1mxu [4m[22mn[24m⟨line‐break⟩
              ([4munderline[24m control command)
              Configure  underlining  of spaces.  If [4mn[24m is 1, start underlining
              of spaces; if [4mn[24m is 0,  stop  underlining  of  spaces.   This  is
              needed  for  the  [1mcu [22mrequest in [1mnroff [22mmode and is ignored other‐
              wise.  This command is a [4mgroff[24m extension.

       [1mxX [4m[22manything[24m⟨line‐break⟩
              ([4mX‐escape[24m control command)
              Send string [4manything[24m uninterpreted to the device.  If  the  line
              following  this  command  starts with a [1m+ [22mcharacter this line is
              interpreted as a continuation line in the following sense.   The
              [1m+ [22mis ignored, but a newline character is sent instead to the de‐
              vice,  the rest of the line is sent uninterpreted.  The same ap‐
              plies to all following lines until the first character of a line
              is not a [1m+ [22mcharacter.  This command is generated  by  the  [4mgroff[0m
              escape  sequence [1m\X[22m.  The line‐continuing feature is a [4mgroff[24m ex‐
              tension.

   [1mObsolete command[0m
       In [4mclassical[24m [4mtroff[24m output, emitting a single glyph was mostly done by a
       very strange command that combined a horizontal move and  the  printing
       of  a  glyph.   It  didn’t have a command code, but is represented by a
       3‐character argument consisting of exactly 2 digits and a character.

       [4mddc[24m    Move right [4mdd[24m (exactly two decimal digits) basic units  [1mu[22m,  then
              print glyph with single‐letter name [4mc[24m.

              In  [4mgroff[24m,  arbitrary  [4msyntactical[24m  [4mspace[24m around and within this
              command is allowed to be added.  Only when a  preceding  command
              on the same line ends with an argument of variable length a sep‐
              arating space is obligatory.  In [4mclassical[24m [4mtroff[24m, large clusters
              of  these  and  other commands were used, mostly without spaces;
              this made such output almost unreadable.

       For modern high‐resolution devices, this command does  not  make  sense
       because the width of the glyphs can become much larger than two decimal
       digits.  In [4mgroff[24m, it is used only for output to the [1mX75[22m, [1mX75-12[22m, [1mX100[22m,
       and  [1mX100-12 [22mdevices.  For others, the commands [1mt [22mand [1mu [22mprovide greater
       functionality and superior troubleshooting capacity.

[1mPostprocessing[0m
       The [4mroff[24m postprocessors are programs that have the  task  to  translate
       the  [4mintermediate[24m [4moutput[24m into actions that are sent to a device.  A de‐
       vice can be some piece of hardware such as a  printer,  or  a  software
       file  format suitable for graphical or text processing.  The [4mgroff[24m sys‐
       tem provides powerful means that make the  programming  of  such  post‐
       processors an easy task.

       There  is  a  library  function that parses the [4mintermediate[24m [4moutput[24m and
       sends the information obtained to the device via  methods  of  a  class
       with a common interface for each device.  So a [4mgroff[24m postprocessor must
       only  redefine  the methods of this class.  For details, see the refer‐
       ence in section “Files” below.

[1mExample[0m
       This section presents the [4mintermediate[24m [4moutput[24m generated from  the  same
       input  for  three  different  devices.   The input is the sentence [4mhell[0m
       [4mworld[24m fed into [4mgroff[24m on the command line.

       • High‐resolution device [4mps[0m

         shell> [1mecho "hell world" | groff -Z -T ps[0m

         x T ps
         x res 72000 1 1
         x init
         p1
         x font 5 TR
         f5
         s10000
         V12000
         H72000
         thell
         wh2500
         tw
         H96620
         torld
         n12000 0
         x trailer
         V792000
         x stop

       This output can be fed into the postprocessor [4mgrops[24m(1) to get its  rep‐
       resentation  as  a  PostScript file, or [4mgropdf[24m(1) to output directly to
       PDF.

       • Low‐resolution device [4mlatin1[0m

         This is similar to the high‐resolution device except that  the  posi‐
         tioning is done at a minor scale.  Some comments (lines starting with
         [4m#[24m)  were added for clarification; they were not generated by the for‐
         matter.

         [1mshell> [22m"hell world" | groff -Z -T latin1

         [4m#[24m [4mprologue[0m
         x T latin1
         x res 240 24 40
         x init
         [4m#[24m [4mbegin[24m [4ma[24m [4mnew[24m [4mpage[0m
         p1
         [4m#[24m [4mfont[24m [4msetup[0m
         x font 1 R
         f1
         s10
         [4m#[24m [4minitial[24m [4mpositioning[24m [4mon[24m [4mthe[24m [4mpage[0m
         V40
         H0
         [4m#[24m [4mwrite[24m [4mtext[24m [4m'hell'[0m
         thell
         [4m#[24m [4minform[24m [4mabout[24m [4ma[24m [4mspace,[24m [4mand[24m [4mdo[24m [4mit[24m [4mby[24m [4ma[24m [4mhorizontal[24m [4mjump[0m
         wh24
         [4m#[24m [4mwrite[24m [4mtext[24m [4m'world'[0m
         tworld
         [4m#[24m [4mannounce[24m [4mline[24m [4mbreak,[24m [4mbut[24m [4mdo[24m [4mnothing[24m [4mbecause[24m [4m...[0m
         n40 0
         [4m#[24m [4m...[24m [4mthe[24m [4mend[24m [4mof[24m [4mthe[24m [4mdocument[24m [4mhas[24m [4mbeen[24m [4mreached[0m
         x trailer
         V2640
         x stop

       This output can be fed into the postprocessor [4mgrotty[24m(1) to get  a  for‐
       matted text document.

       • Classical style output

         As  a  computer  monitor has a very low resolution compared to modern
         printers the [4mintermediate[24m [4moutput[24m for the X devices can use the  jump‐
         and‐write command with its 2‐digit displacements.

         [1mshell> [22m"hell world" | groff -Z -T X100

         x T X100
         x res 100 1 1
         x init
         p1
         x font 5 TR
         f5
         s10
         V16
         H100
         [4m#[24m [4mwrite[24m [4mtext[24m [4mwith[24m [4mold‐style[24m [4mjump‐and‐write[24m [4mcommand[0m
         ch07e07l03lw06w11o07r05l03dh7
         n16 0
         x trailer
         V1100
         x stop

       This   output  can  be  fed  into  the  postprocessor  [4mxditview[24m(1x)  or
       [4mgxditview[24m(1) for displaying in X.

       Due to the obsolete jump‐and‐write command, the text  clusters  in  the
       classical output are almost unreadable.

[1mCompatibility[0m
       The [4mintermediate[24m [4moutput[24m language of the [4mclassical[24m [4mtroff[24m was first docu‐
       mented in [CSTR #97].  The [4mgroff[24m [4mintermediate[24m [4moutput[24m format is compati‐
       ble with this specification except for the following features.

       • The classical quasi device independence is not yet implemented.

       • The  old  hardware was very different from what we use today.  So the
         [4mgroff[24m devices are also fundamentally different from the ones in [4mclas‐[0m
         [4msical[24m [4mtroff[24m.  For example, the classical PostScript device was called
         [4mpost[24m and had a resolution of 720 units per inch, while [4mgroff[24m’s [4mps[24m de‐
         vice has a resolution of 72000 units per inch.  Maybe, by  implement‐
         ing  some  rescaling  mechanism similar to the classical quasi device
         independence, these could be integrated into modern [4mgroff[24m.

       • The B‐spline command [1mD~ [22mis correctly handled by the [4mintermediate[24m [4mout‐[0m
         [4mput[24m parser, but the drawing routines aren’t implemented  in  some  of
         the postprocessor programs.

       • The  argument  of the commands [1ms [22mand [1mx H [22mhas the implicit unit scaled
         point [1mz [22min [4mgroff[24m, while [4mclassical[24m [4mtroff[24m had point ([1mp[22m).  This isn’t an
         incompatibility, but a compatible extension, for both units  coincide
         for  all devices without a [4msizescale[24m parameter, including all classi‐
         cal and the [4mgroff[24m  text  devices.   The  few  [4mgroff[24m  devices  with  a
         sizescale  parameter  either  did not exist, had a different name, or
         seem to have had a different resolution.  So conflicts with classical
         devices are very unlikely.

       • The position changing after the commands [1mDp[22m, [1mDP[22m, and [1mDt [22mis illogical,
         but as old versions of groff used this feature it is kept for compat‐
         ibility reasons.

       The differences between [4mgroff[24m and [4mclassical[24m  [4mtroff[24m  are  documented  in
       [4mgroff_diff[24m(7).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/font/dev[24mname[4m/DESC[0m
              describes the output device [4mname[24m.

[1mAuthors[0m
       James  Clark  wrote  an early version of this document, which described
       only the differences between  AT&T  device‐independent  [4mtroff[24m’s  output
       format  and  that  of  GNU  [4mroff[24m.   The  present version was completely
       rewritten in 2001 by Bernd Warken ⟨groff-bernd.warken-72@web.de⟩.

[1mSee also[0m
       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher  and  Werner
       Lemberg,  is the primary [4mgroff[24m manual.  You can browse it interactively
       with “info groff”.

       “Troff User’s Manual” by Joseph F. Ossanna, 1976 (revised by  Brian  W.
       Kernighan,  1992),  AT&T  Bell Laboratories Computing Science Technical
       Report No. 54, widely called simply “CSTR #54”, documents the language,
       device and font description file formats, and device‐independent output
       format referred to collectively in [4mgroff[24m documentation as “AT&T [4mtroff[24m”.

       “A Typesetter‐independent TROFF” by Brian W. Kernighan, 1982, AT&T Bell
       Laboratories Computing Science Technical Report No. 97, provides  addi‐
       tional  insights  into the device and font description file formats and
       device‐independent output format.

       [4mgroff[24m(1)
              documents the [1m-Z [22moption and contains pointers to  further  [4mgroff[0m
              documentation.

       [4mgroff[24m(7)
              describes the [4mgroff[24m language, including its escape sequences and
              system of units.

       [4mgroff_font[24m(5)
              details the device scaling parameters of device [4mDESC[24m files.

       [4mtroff[24m(1)
              generates  the device‐independent intermediate output documented
              here.

       [4mroff[24m(7)
              presents historical aspects and the general  structure  of  [4mroff[0m
              systems.

       [4mgroff_diff[24m(7)
              enumerates  differences between the intermediate output produced
              by AT&T [4mtroff[24m and that of [4mgroff[24m.

       [4mgxditview[24m(1)
              is a viewer for intermediate output.

       [4mRoff.js[0m
              ⟨https://github.com/Alhadis/Roff.js/⟩ is a viewer for intermedi‐
              ate output written in JavaScript.

       [4mgrodvi[24m(1), [4mgrohtml[24m(1), [4mgrolbp[24m(1), [4mgrolj4[24m(1), [4mgropdf[24m(1),  [4mgrops[24m(1),  and
       [4mgrotty[24m(1) are [4mgroff[24m postprocessors.

groff 1.23.0                      5 July 2023                     [4mgroff_out[24m(5)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_tmac[24m(5)                 File Formats Manual                [4mgroff_tmac[24m(5)

[1mName[0m
       groff_tmac - macro files in the GNU [4mroff[24m typesetting system

[1mDescription[0m
       Definitions of macros, strings, and registers for use in a [4mroff[24m(7) doc‐
       ument  can  be collected into [4mmacro[24m [4mfiles[24m, [4mroff[24m input files designed to
       produce no output themselves but instead ease the preparation of  other
       [4mroff[24m  documents.   There  is  no syntactical difference between a macro
       file and any other [4mroff[24m document; only its  purpose  distinguishes  it.
       When  a macro file is installed at a standard location, named according
       to a certain convention, and suitable for use by a general audience, it
       is termed a [4mmacro[24m [4mpackage[24m.  Macro packages can be loaded  by  supplying
       the [1m-m [22moption to [4mtroff[24m(1) or a [4mgroff[24m front end.

       Each  macro  package stores its macro, string, and register definitions
       in one or more [4mtmac[24m files.  This name originated in early Unix  culture
       as an abbreviation of “[4mtroff[24m macros”.

       A  macro file must have a name in the form name[4m.tmac[24m (or [4mtmac.[24mname) and
       be placed in a “[4mtmac[24m directory” to be loadable with the [1m-m[4m[22mname[24m  option.
       Section  “Environment”  of  [4mtroff[24m(1) lists these directories.  Alterna‐
       tively, a [4mgroff[24m document requiring a macro file can load  it  with  the
       [1mmso [22m(“macro source”) request.

       Like  any  other  [4mroff[24m  document, a macro file can use the “[1mso[22m” request
       (“source”) to load further files relative to its own location.

       Macro files are named for their  most  noteworthy  application,  but  a
       macro  file  need  not  define  any  macros.  It can restrict itself to
       defining registers and strings or invoking other  [4mgroff[24m  requests.   It
       can even be empty.

[1mMacro packages[0m
       Macro packages come in two varieties; those which assume responsibility
       for  page  layout  and  other critical functions (“major” or “full‐ser‐
       vice”) and those which do not  (“supplemental”  or  “auxiliary”).   GNU
       [4mroff[24m provides most major macro packages found in AT&T and BSD Unix sys‐
       tems,  an  additional full‐service package, and many supplemental pack‐
       ages.  Multiple full‐service macro packages cannot be used by the  same
       document.   Auxiliary packages can generally be freely combined, though
       attention to their use of the [4mgroff[24m language name  spaces  for  identi‐
       fiers  (particularly registers, macros, strings, and diversions) should
       be paid.  Name space management was a  significant  challenge  in  AT&T
       [4mtroff[24m; [4mgroff[24m’s support for arbitrarily long identifiers affords few ex‐
       cuses  for  name  collisions, apart from attempts at compatibility with
       the demands of historical documents.

   [1mMan pages[0m
       [4man[0m
       [4mman[24m    [4man[24m is used to compose man pages in  the  format  originating  in
              Version  7  Unix  (1979).  It has a small macro interface and is
              widely used; see [4mgroff_man[24m(7).

       [4mdoc[0m
       [4mmdoc[24m   [4mdoc[24m is used to compose man pages in the  format  originating  in
              4.3BSD‐Reno (1990).  It provides many more features than [4man[24m, but
              is  also  larger,  more  complex, and not as widely adopted; see
              [4mgroff_mdoc[24m(7).

       Because readers of man pages often do not know in advance which  macros
       are used to format a given document, a wrapper is available.

       [4mandoc[0m
       [4mmandoc[24m This  macro  file, specific to [4mgroff[24m, recognizes whether a docu‐
              ment uses [4mman[24m or [4mmdoc[24m format and loads the  corresponding  macro
              package.   Multiple man pages, in either format, can be handled;
              [4mandoc[24m reloads each macro package as necessary.

   [1mFull‐service packages[0m
       The packages in this section provide a complete set of macros for writ‐
       ing documents of any kind, up to whole  books.   They  are  similar  in
       functionality; it is a matter of taste which one to use.

       [4mme[24m     The classical [4mme[24m macro package; see [4mgroff_me[24m(7).

       [4mmm[24m     The semi‐classical [4mmm[24m macro package; see [4mgroff_mm[24m(7).

       [4mmom[24m    The [4mmom[24m macro package, only available in groff.  As this was not
              based on other packages, it was freely designed as quite a nice,
              modern macro package.  See [4mgroff_mom[24m(7).

       [4mms[24m     The classical [4mms[24m macro package; see [4mgroff_ms[24m(7).

   [1mLocalization packages[0m
       For  Western languages, the localization file sets the hyphenation mode
       and loads hyphenation patterns and exceptions.  Localization files  can
       also adjust the date format and provide translations of strings used by
       some  of the full‐service macro packages; alter the input encoding (see
       the next section); and change the amount of  additional  inter‐sentence
       space.   For Eastern languages, the localization file defines character
       classes and sets flags on them.  By default, [4mtroffrc[24m loads  the  local‐
       ization file for English.

       [4mtrans[24m  loads  localized  strings  used  by various macro packages after
              their localized forms have been prepared by a localization macro
              file.

       [4mgroff[24m provides the following localization files.

       [4mcs[24m     Czech; localizes [4mman[24m, [4mme[24m, [4mmm[24m, [4mmom[24m, and [4mms[24m.  Sets the  input  en‐
              coding to Latin‐2 by loading [4mlatin2.tmac[24m.

       [4mde[0m
       [4mden[24m    German;  localizes [4mman[24m, [4mme[24m, [4mmm[24m, [4mmom[24m, and [4mms[24m.  Sets the input en‐
              coding to Latin‐1 by loading [4mlatin1.tmac[24m.

              [4mde.tmac[24m selects hyphenation patterns for  traditional  orthogra‐
              phy, and [4mden.tmac[24m does the same for the new orthography (“Recht‐
              schreibreform”).

       [4men[24m     English.

       [4mfr[24m     French;  localizes [4mman[24m, [4mme[24m, [4mmm[24m, [4mmom[24m, and [4mms[24m.  Sets the input en‐
              coding to Latin‐9 by loading [4mlatin9.tmac[24m.

       [4mit[24m     Italian; localizes [4mman[24m, [4mme[24m, [4mmm[24m, [4mmom[24m, and [4mms[24m.

       [4mja[24m     Japanese.

       [4msv[24m     Swedish; localizes [4mman[24m, [4mme[24m, [4mmm[24m, [4mmom[24m, and [4mms[24m.  Sets the input en‐
              coding to Latin‐1 by loading [4mlatin1.tmac[24m.  Some of the localiza‐
              tion of the [4mmm[24m package is handled separately; see [4mgroff_mmse[24m(7).

       [4mzh[24m     Chinese.

   [1mInput encodings[0m
       [4mlatin1[0m
       [4mlatin2[0m
       [4mlatin5[0m
       [4mlatin9[24m are various ISO 8859 input encodings  supported  by  [4mgroff[24m.   On
              systems  using  ISO character encodings, [4mgroff[24m loads [4mlatin1.tmac[0m
              automatically  at  startup.   A  document  that  uses   Latin‐2,
              Latin‐5,  or Latin‐9 can specify one of these alternative encod‐
              ings.

       [4mcp1047[24m provides support for EBCDIC‐based systems.  On those  platforms,
              [4mgroff[24m loads [4mcp1047.tmac[24m automatically at startup.

       Because  different input character codes constitute valid GNU [4mtroff[24m in‐
       put on ISO and EBCDIC systems, the [4mlatin[24m macro files cannot be used  on
       EBCDIC systems, and [4mcp1047[24m cannot be used on ISO systems.

   [1mAuxiliary packages[0m
       The  macro  packages  in  this section are not intended for stand‐alone
       use, but can add functionality to any other macro package or  to  plain
       (“raw”) [4mgroff[24m documents.

       [4m62bit[24m  provides  macros  for  addition, multiplication, and division of
              62‐bit integers (allowing safe multiplication of  signed  31‐bit
              integers, for example).

       [4mhdtbl[24m  allows  the  generation  of tables using a syntax similar to the
              HTML table model.  This Heidelberger table macro package is  not
              a preprocessor, which can be useful if the contents of table en‐
              tries  are  determined  by macro calls or string interpolations.
              Compare to [4mtbl[24m(1).  It works only with the [1mps [22mand [1mpdf [22moutput de‐
              vices.  See [4mgroff_hdtbl[24m(7).

       [4mpapersize[0m
              enables the paper format to be set on the command line by giving
              a “[1m-d paper=[4m[22mformat[24m” option to [4mtroff[24m.  Possible values for [4mformat[0m
              are the ISO and  DIN  formats  “[1mA0[22m–[1mA6[22m”,  “[1mB0[22m–[1mB6[22m”,  “[1mC0[22m–[1mC6[22m”,  and
              “[1mD0[22m–[1mD6[22m”;   the   U.S.   formats  “[1mletter[22m”,  “[1mlegal[22m”,  “[1mtabloid[22m”,
              “[1mledger[22m”, “[1mstatement[22m”, and “[1mexecutive[22m”; and the envelope formats
              “[1mcom10[22m”, “[1mmonarch[22m”, and “[1mDL[22m”.  All formats, even those  for  en‐
              velopes,  are in portrait orientation: the length measurement is
              vertical.  Appending “l” (ell) to any of these denotes landscape
              orientation instead.  This macro file assumes one‐inch  horizon‐
              tal  margins,  and  sets  registers recognized by the [4mgroff[24m [4mman[24m,
              [4mmdoc[24m, [4mmm[24m, [4mmom[24m, and [4mms[24m packages to  configure  them  accordingly.
              If  you want different margins, you will need to use those pack‐
              ages’ facilities, or [4mtroff[24m [1mll [22mand/or [1mpo [22mrequests to adjust them.
              An output device typically requires command‐line options [1m-p  [22mand
              [1m-l  [22mto  override  the  paper dimensions and orientation, respec‐
              tively, defined in its [4mDESC[24m file; see subsection “Paper  format”
              of  [4mgroff[24m(1).   This macro file is normally loaded at startup by
              the [4mtroffrc[24m file when formatting for a typesetting  device  (but
              not a terminal).

       [4mpdfpic[24m provides  a  single macro, [1mPDFPIC[22m, to include a PDF graphic in a
              document using features of the [1mpdf  [22moutput  driver.   For  other
              output  devices, [1mPDFPIC [22mcalls [1mPSPIC[22m, with which it shares an in‐
              terface (see below).  This macro  file  is  normally  loaded  at
              startup by the [4mtroffrc[24m file.

       [4mpic[24m    supplies  definitions  of the macros [1mPS[22m, [1mPE[22m, and [1mPF[22m, usable with
              the [4mpic[24m(1) preprocessor.  They center each picture.  Use  it  if
              your document does not use a full‐service macro package, or that
              package  does  not supply working [4mpic[24m macro definitions.  Except
              for [4mman[24m and [4mmdoc[24m, those provided with [4mgroff[24m already do  so  (ex‐
              ception: [4mmm[24m employs the name [1mPF [22mfor a different purpose).

       [4mpspic[24m  provides a macro, [1mPSPIC[22m, that includes a PostScript graphic in a
              document.   The  [1mps[22m, [1mdvi[22m, [1mhtml[22m, and [1mxhtml [22moutput devices support
              such inclusions; for all other drivers, the  image  is  replaced
              with  a  rectangular  border  of  the  same size.  [4mpspic.tmac[24m is
              loaded at startup by the [4mtroffrc[24m file.

              Its syntax is as follows.

                     [1m.PSPIC [22m[[1m-L[22m|[1m-R[22m|[1m-C[22m|[1m-I [4m[22mn[24m] [4mfile[24m [[4mwidth[24m [[4mheight[24m]]

              [4mfile[24m is the name of the PostScript file; [4mwidth[24m and  [4mheight[24m  give
              the  desired  width and height of the image.  If neither a [4mwidth[0m
              nor a [4mheight[24m argument is specified, the  image’s  natural  width
              (as given in the file’s bounding box) or the current line length
              is used as the width, whatever is smaller.  The [4mwidth[24m and [4mheight[0m
              arguments  may  have scaling units attached; the default scaling
              unit is [1mi[22m.  [1mPSPIC [22mscales the graphic uniformly in the horizontal
              and vertical directions so that it is no more  than  [4mwidth[24m  wide
              and  [4mheight[24m  high.   Option [1m-C [22mcenters the graphic horizontally;
              this is the default.   [1m-L  [22mand  [1m-R  [22mleft‐  and  right‐align  the
              graphic,  respectively.  [1m-I [22mindents the graphic by [4mn[24m (with a de‐
              fault scaling unit of [1mm[22m).

              To use [1mPSPIC [22mwithin a diversion, we recommend extending it  with
              the  following  code,  assuring  that the diversion’s width com‐
              pletely covers the image’s width.

                     .am PSPIC
                     .  vpt 0
                     \h'(\\n[ps-offset]u + \\n[ps-deswid]u)'
                     .  sp -1
                     .  vpt 1
                     ..

              Failure to load [1mPSPIC[22m’s image argument is not  an  error.   (The
              [1mpsbb  [22mrequest  does  issue an error diagnostic.)  To make such a
              failure fatal, append to the [1mpspic*error-hook [22mmacro.

                     .am pspic*error-hook
                     .  ab
                     ..

       [4mptx[24m    provides a macro, [1mxx[22m, to format permuted index entries  as  pro‐
              duced  by the GNU [4mptx[24m(1) program.  If your formatting needs dif‐
              fer, copy the macro into your document  and  adapt  it  to  your
              needs.

       [4mrfc1345[0m
              defines  special  character escape sequences named for the glyph
              mnemonics specified in RFC 1345 and the digraph table of the Vim
              text editor.  See [4mgroff_rfc1345[24m(7).

       [4msboxes[24m offers an interface to the “[1mpdf: background[22m” device control com‐
              mand supported by [4mgropdf[24m(1).  Using this package, [4mgroff[24m [4mms[24m docu‐
              ments can draw colored rectangles beneath any output.

              [1m.BOXSTART SHADED [4m[22mcolor[24m [1mOUTLINED [4m[22mcolor[24m [1mINDENT [4m[22msize[24m [1mWEIGHT [4m[22msize[0m
                     begins a box, where the argument after [1mSHADED  [22mgives  the
                     fill  color  and  that  after  [1mOUTLINED [22mthe border color.
                     Omit the former to get a borderless filled  box  and  the
                     latter  for  a border with no fill.  The specified [1mWEIGHT[0m
                     is used if the box is [1mOUTLINED[22m.

                     [1mINDENT [22mprecedes a value which leaves a  gap  between  the
                     border and the contents inside the box.

                     Each  [4mcolor[24m  must be a defined [4mgroff[24m color name, and each
                     [4msize[24m a valid [4mgroff[24m numeric expression.  The keyword/value
                     pairs can be specified in any order.

              Boxes can be stacked, so you can start a box within another box;
              usually the later boxes would be  smaller  than  the  containing
              box,  but  this  is not enforced.  When using [1mBOXSTART[22m, the left
              position is the current indent minus the [1mINDENT [22min the  command,
              and  the  right position is the left position (calculated above)
              plus the current line length and twice the indent.

              [1m.BOXSTOP[0m
                     takes no parameters.  It closes the most recently started
                     box at the current vertical  position  after  adding  its
                     [1mINDENT [22mspacing.

              Your  [4mgroff[24m  documents  can  conditionally  exercise  the [4msboxes[0m
              macros.  The register [1mGSBOX [22mis defined if the package is loaded,
              and interpolates a true value if the [1mpdf  [22moutput  device  is  in
              use.

              [4msboxes[24m furthermore hooks into the [4mgroff_ms[24m(7) package to receive
              notifications  when  footnotes are growing, so that it can close
              boxes on a page before footnotes are printed.  When that  condi‐
              tion  obtains, [4msboxes[24m will close open boxes two points above the
              footnote separator and re‐open them on  the  next  page.   (This
              amount probably will not match the box’s [1mINDENT[22m.)

              See “Using PDF boxes with [4mgroff[24m and the [4mms[24m macros” ⟨file:///usr/
              share/doc/groff-1.23.0/msboxes.pdf⟩ for a demonstration.

       [4mtrace[24m  aids  the  debugging  of [4mgroff[24m documents by tracing macro calls.
              See [4mgroff_trace[24m(7).

       [4mwww[24m    defines   macros   corresponding   to   HTML   elements.     See
              [4mgroff_www[24m(7).

[1mNaming[0m
       AT&T  [4mnroff[24m  and  [4mtroff[24m  were implemented before the conventions of the
       modern C [4mgetopt[24m(3) call evolved, and used a  naming  scheme  for  macro
       packages  that looks odd to modern eyes.  Macro packages were typically
       loaded using the [1m-m [22moption to the formatter; when directly followed  by
       its  argument without an intervening space, this looked like a long op‐
       tion preceded by a single minus—a sensation in the computer stone  age.
       Macro  packages  therefore  came to be known by names that started with
       the letter “m”, which was omitted from the name of the  macro  file  as
       stored  on  disk.  For example, the manuscript macro package was stored
       as [4mtmac.s[24m and loaded with the option [1m-ms[22m.

       [4mgroff[24m commands permit space between an option and  its  argument.   The
       syntax  “[1mgroff  -m s[22m” makes the macro file name more clear but may sur‐
       prise users familiar with the original  convention,  unaware  that  the
       package’s  “real”  name  was  “s” all along.  For such packages of long
       pedigree, [4mgroff[24m accommodates different users’ expectations by supplying
       wrapper macro files that load  the  desired  file  with  [1mmso  [22mrequests.
       Thus, all of “[1mgroff -m s[22m”, “[1mgroff -m ms[22m”, “[1mgroff -ms[22m”, and “[1mgroff -mms[22m”
       serve to load the manuscript macros.

       Wrappers  are  not  provided  for packages of more recent vintage, like
       [4mwww.tmac[24m.

       As noted in passing above, AT&T [4mtroff[24m named macro  files  in  the  form
       [4mtmac.[24mname.   It  has  since become conventional in operating systems to
       use a suffixed file name extension to suggest a file type or format.

[1mInclusion[0m
       The traditional method of employing a macro package is to  specify  the
       [1m-m  [4m[22mpackage[24m  option  to the formatter, which then reads [4mpackage[24m’s macro
       file prior to any input files.  Historically, [4mpackage[24m was sought  in  a
       file  named  [4mtmac.[24mpackage  (that is, with a “[1mtmac.[22m” prefix).  GNU [4mtroff[0m
       searches for package[4m.tmac[24m in the macro path; if not found, it looks for
       [4mtmac.[24mpackage instead, and vice versa.

       Alternatively, one could include a macro file by using the request “[1m.so[0m
       [4mfile‐name[24m” in the document; [4mfile‐name[24m is resolved relative to the loca‐
       tion of the input document.  GNU [4mtroff[24m offers an  improved  feature  in
       the  similar  request “[1mmso [4m[22mpackage‐file‐name[24m”, which searches the macro
       path for [4mpackage‐file‐name[24m.  Because its argument is a file  name,  its
       “[1m.tmac[22m”  component  must be included for the file to be found; however,
       as a convenience, if opening it fails, [1mmso [22mstrips any such  suffix  and
       tries again with a “[1mtmac.[22m” prefix, and vice versa.

       If  a  sourced  file requires preprocessing, for example if it includes
       [4mtbl[24m tables or [4meqn[24m equations, the preprocessor [4msoelim[24m(1) must  be  used.
       This can be achieved with a pipeline or, in [4mgroff[24m, by specifying the [1m-s[0m
       option to the formatter (or front end).  [4mman[24m(1) librarian programs gen‐
       erally call [4msoelim[24m automatically.  (Macro packages themselves generally
       do not require preprocessing.)

[1mWriting macros[0m
       A  [4mroff[24m(7)  document is a text file that is enriched by predefined for‐
       matting constructs, such as requests, escape  sequences,  strings,  nu‐
       meric  registers,  and macros from a macro package.  These elements are
       described in [4mroff[24m(7).

       To give a document a personal style, it is most useful  to  extend  the
       existing elements by defining some macros for repeating tasks; the best
       place  for  this is near the beginning of the document or in a separate
       file.

       Macros without arguments are just like strings.  But the full power  of
       macros  occurs when arguments are passed with a macro call.  Within the
       macro definition, the arguments are available as the  escape  sequences
       [1m\$1[22m,  ...,  [1m\$9[22m,  [1m\$[[22m...[1m][22m, [1m\$*[22m, and [1m\$@[22m, the name under which the macro
       was called is in [1m\$0[22m, and  the  number  of  arguments  is  in  register
       [1m\n[.$][22m; see [4mgroff[24m(7).

   [1mDraft mode[0m
       Writing groff macros is easy when the escaping mechanism is temporarily
       disabled.   In groff, this is done by enclosing the macro definition(s)
       within a pair of [1m.eo [22mand [1m.ec [22mrequests.  Then the body in the macro def‐
       inition is just like a normal part of the document — text  enhanced  by
       calls  of  requests, macros, strings, registers, etc.  For example, the
       code above can be written in a simpler way by

              .eo
              .ds midpart was called with the following
              .de print_args
              \f[I]\$0\f[] \*[midpart] \n[.$] arguments:
              \$*
              ..
              .ec

       Unfortunately, draft mode cannot be used universally.  Although  it  is
       good  enough for defining normal macros, draft mode fails with advanced
       applications, such as indirectly defined strings, registers,  etc.   An
       optimal  way is to define and test all macros in draft mode and then do
       the backslash doubling as a final step; do not forget to remove the [4m.eo[0m
       request.

   [1mTips for macro definitions[0m
       •      Start every line with a dot, for example, by using the groff re‐
              quest [1m.nop [22mfor text lines, or write your own macro that  handles
              also text lines with a leading dot.

                     .de Text
                     .  if (\\n[.$] == 0) \
                     .    return
                     .  nop \)\\$*\)
                     ..

       •      Write  a comment macro that works both for copy and draft modes;
              since the escape character is off in draft mode,  trouble  might
              occur  when comment escape sequences are used.  For example, the
              following macro just ignores its arguments, so it  acts  like  a
              comment line:

                     .de c
                     ..
                     .c This is like a comment line.

       •      In  long  macro  definitions, make ample use of comment lines or
              almost‐empty lines (this is, lines which have a leading dot  and
              nothing else) for a better structuring.

       •      To  increase  readability,  use groff’s indentation facility for
              requests and macro calls (arbitrary whitespace after the leading
              dot).

   [1mDiversions[0m
       Diversions can be used to implement  quite  advanced  programming  con‐
       structs.   They  are comparable to pointers to large data structures in
       the C programming language, but their usage is quite different.

       In their simplest form, diversions are multi‐line strings,  but  diver‐
       sions  get  their power when used dynamically within macros.  The (for‐
       matted) information stored in a diversion can be retrieved  by  calling
       the diversion just like a macro.

       Most  of the problems arising with diversions can be avoided if you re‐
       member that diversions always store complete lines.   Using  diversions
       when the line buffer has not been flushed produces strange results; not
       knowing  this,  many  people get desperate about diversions.  To ensure
       that a diversion works, add line breaks at the  right  places.   To  be
       safe,  enclose  everything that has to do with diversions within a pair
       of line breaks; for example, by explicitly using  [1m.br  [22mrequests.   This
       rule  should  be  applied to diversion definition, both inside and out‐
       side, and to all calls of diversions.  This is a bit of  overkill,  but
       it works nicely.

       (If  you really need diversions which should ignore the current partial
       line, use environments to save the current partial line and/or use  the
       [1m.box [22mrequest.)

       The  most  powerful  feature  using  diversions is to start a diversion
       within a macro definition and end it within another macro.  Then every‐
       thing between each call of this macro pair is stored within the  diver‐
       sion and can be manipulated from within the macros.

[1mAuthors[0m
       This  document  was  written by Bernd Warken ⟨groff-bernd.warken-72@web
       .de⟩, Werner Lemberg ⟨wl@gnu.org⟩, and G. Branden  Robinson  ⟨g.branden
       .robinson@gmail.com⟩.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       The  Filesystem  Hierarchy  Standard ⟨https://wiki.linuxfoundation.org/
       lsb/fhs⟩ is maintained by the Linux Foundation.

       [4mgroff[24m(1)
              is an overview of the [4mgroff[24m system.

       [4mgroff_man[24m(7),
       [4mgroff_mdoc[24m(7),
       [4mgroff_me[24m(7),
       [4mgroff_mm[24m(7),
       [4mgroff_mom[24m(7),
       [4mgroff_ms[24m(7),
       [4mgroff_rfc1345[24m(7),
       [4mgroff_trace[24m(7),
               and
       [4mgroff_www[24m(7)
              are [4mgroff[24m macro packages.

       [4mgroff[24m(7)
              summarizes the language recognized by GNU [4mtroff[24m.

       [4mtroff[24m(1)
              documents the default macro file search path.

groff 1.23.0                      5 July 2023                    [4mgroff_tmac[24m(5)
───────────────────────────────────────────────────────────────────────────────
[4mgroff[24m(7)               Miscellaneous Information Manual               [4mgroff[24m(7)

[1mName[0m
       groff - GNU [4mroff[24m language reference

[1mDescription[0m
       [4mgroff[24m is short for GNU [4mroff[24m, a free reimplementation of  the  AT&T  de‐
       vice‐independent [4mtroff[24m typesetting system.  See [4mroff[24m(7) for a survey of
       and background on [4mroff[24m systems.

       This  document  is  intended as a reference.  The primary [4mgroff[24m manual,
       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher  and  Werner
       Lemberg,  is  a  better resource for learners, containing many examples
       and much discussion.  It is written in Texinfo; you can browse  it  in‐
       teractively  with  “info  groff”.   Additional formats, including plain
       text,  HTML,  DVI,  and  PDF,  may  be  available  in   [4m/usr/share/doc/[0m
       [4mgroff-1.23.0[24m.

       [4mgroff[24m  is also a name for an extended dialect of the [4mroff[24m language.  We
       use “roff” to denote features that are universal, or nearly  so,  among
       implementations  of this family.  We apply the term “groff” to the lan‐
       guage documented here, the GNU implementation of  the  overall  system,
       the project that develops that system, and the command of that name.

       GNU  [4mtroff[24m,  installed  on this system as [4mtroff[24m(1), is the [4mformatter:[24m a
       program that reads device and font descriptions ([4mgroff_font[24m(5)), inter‐
       prets the [4mgroff[24m language expressed in text input files, and  translates
       that  input into a device‐independent output format ([4mgroff_out[24m(5)) that
       is usually then post‐processed by an output  driver  to  produce  Post‐
       Script, PDF, HTML, DVI, or terminal output.

[1mInput format[0m
       Input  to  GNU [4mtroff[24m is organized into lines separated by the Unix new‐
       line character (U+000A), and must be in one of two character  encodings
       it can recognize: IBM code page 1047 on EBCDIC systems, and ISO Latin‐1
       (8859‐1)  otherwise.   Use of ISO 646‐1991:IRV (“US‐ASCII”) or (equiva‐
       lently) the “Basic Latin” subset of ISO  10646  (“Unicode”)  is  recom‐
       mended;  see  [4mgroff_char[24m(7).   The  [4mpreconv[24m(1)  preprocessor transforms
       other encodings, including UTF‐8, to satisfy [4mtroff[24m’s requirements.

[1mSyntax characters[0m
       Several input characters are syntactically significant to [4mgroff[24m.

       .   A dot at the beginning of an input line marks it as a [4mcontrol[24m [4mline.[0m
           It can also follow the [1m.el [22mand [1m.nop [22mrequests, and the condition  in
           [1m.if[22m,  [1m.ie[22m,  and [1m.while [22mrequests.  The control character invokes re‐
           quests and calls macros by the name that follows it.  The  [1m.cc  [22mre‐
           quest can change the control character.

       '   The  neutral  apostrophe  is the [4mno‐break[24m [4mcontrol[24m [4mcharacter,[24m recog‐
           nized where the control character is.  It  suppresses  the  (first)
           break  implied  by the [1m.bp[22m, [1m.cf[22m, [1m.fi[22m, [1m.fl[22m, [1m.in[22m, [1m.nf[22m, [1m.rj[22m, [1m.sp[22m, [1m.ti[22m,
           and [1m.trf [22mrequests.  The requested operation  takes  effect  at  the
           next  break.  It makes [1m.br [22mnilpotent.  The no‐break control charac‐
           ter can be changed with the [1m.c2 [22mrequest.  When formatted,  “[1m'[22m”  may
           be typeset as a typographical quotation mark; use the [1m\[aq] [22mspecial
           character escape sequence to format a neutral apostrophe glyph.

       "   The neutral double quote can be used to enclose arguments to macros
           and  strings,  and  is required if those arguments contain space or
           tab characters.  In the [1m.ds[22m, [1m.ds1[22m, [1m.as[22m, and [1m.as1 [22mrequests, an  ini‐
           tial neutral double quote in the second argument is stripped off to
           allow  embedding  of leading spaces.  To include a double quote in‐
           side a quoted argument, use the [1m\[dq] [22mspecial character escape  se‐
           quence (which also serves to typeset the glyph in text).

       \   A  backslash  introduces  an escape sequence.  The escape character
           can be changed with the [1m.ec [22mrequest; [1m.eo [22mdisables  escape  sequence
           recognition.   Use  the  [1m\[rs] [22mspecial character escape sequence to
           format a backslash glyph, and [1m\e [22mto typeset the glyph of  the  cur‐
           rent escape character.

       (   An opening parenthesis is special only in certain escape sequences;
           when  recognized,  it introduces an argument of exactly two charac‐
           ters.  [4mgroff[24m offers the more flexible square bracket syntax.

       [   An opening bracket is special only  in  certain  escape  sequences;
           when  recognized,  it  introduces an argument (list) of any length,
           not including a closing bracket.

       ]   A closing bracket is special only when an escape sequence using  an
           opening  bracket as an argument delimiter is being interpreted.  It
           ends the argument (list).

       Additionally, the Control+A character (U+0001) in text  is  interpreted
       as a [4mleader[24m (see below).

       Horizontal  white space characters are significant to [4mgroff,[24m but trail‐
       ing spaces on text lines are ignored.

       [4mspace[24m   Space characters separate  arguments  in  request  invocations,
               macro calls, and string interpolations.  In text, they separate
               words.   Multiple adjacent space characters in text cause [4mgroff[0m
               to attempt end‐of‐sentence detection on the preceding word (and
               trailing punctuation).  The amount of space between  words  and
               sentences  is  controlled  by the [1m.ss [22mrequest.  When filling is
               enabled (the default), a line may be broken at a  space.   When
               adjustment  is enabled (the default), inter‐word spaces are ex‐
               panded until the output line reaches the configured length.  An
               adjustable but non‐breaking space is available with [1m\~[22m.  To get
               a space of fixed width, use one of the escape  sequences  ‘[1m\  [22m’
               (the  escape character followed by a space), [1m\0[22m, [1m\|[22m, [1m\^[22m, or [1m\h[22m;
               see section “Escape sequences” below.

       [4mnewline[24m In text, a newline puts an inter‐word  space  onto  the  output
               and,  if  filling is enabled, triggers end‐of‐sentence recogni‐
               tion on the preceding text.  See  section  “Line  continuation”
               below.

       [4mtab[24m     A  tab character in text causes the drawing position to advance
               to the next defined tab stop.

[1mTabs and leaders[0m
       The formatter interprets input horizontal tab characters  (“tabs”)  and
       Control+A  characters  (“leaders”) into movements to the next tab stop.
       Tabs simply move to the next tab stop; leaders place enough periods  to
       fill  the space.  Tab stops are by default located every half inch mea‐
       sured from the drawing position corresponding to the beginning  of  the
       input  line;  see section “Page geometry” of [4mroff[24m(7).  Tabs and leaders
       do not cause breaks and therefore do not interrupt filling.  Tab  stops
       can  be  configured with the [1mta [22mrequest, and tab and leader glyphs with
       the [1mtc [22mand [1mlc [22mrequests, respectively.

[1mLine continuation[0m
       When filling is enabled, input and output line breaks generally do  not
       correspond.  The [4mroff[24m language therefore distinguishes input and output
       line continuation.

       A backslash [1m\ [22mimmediately followed by a newline, sometimes discussed as
       [1m\[4m[22mnewline[24m,  suppresses  the  effects  of that newline on the input.  The
       next input line thus retains the classification of its predecessor as a
       control or text line.  [1m\[4m[22mnewline[24m is useful for managing line lengths  in
       the  input  during document maintenance; you can break an input line in
       the middle of a request invocation, macro  call,  or  escape  sequence.
       Input  line continuation is invisible to the formatter, with two excep‐
       tions: the [1m| [22moperator recognizes the new input line, and the input line
       counter register [1m.c [22mis incremented.

       The [1m\c [22mescape sequence continues an [4moutput[24m line.  Nothing on the  input
       line  after  it is formatted.  In contrast to [1m\[4m[22mnewline[24m, a line after [1m\c[0m
       is treated as a new input line, so a control character is recognized at
       its beginning.  The visual results depend on  whether  filling  is  en‐
       abled.   An  intervening control line that causes a break overrides [1m\c[22m,
       flushing out the pending output line in the usual  way.   The  register
       [1m.int  [22mcontains  a  positive value if the last output line was continued
       with [1m\c[22m; this datum is associated with the environment.

[1mColors[0m
       [4mgroff[24m supports color output with a variety of color spaces and up to 16
       bits per channel.  Some devices, particularly terminals,  may  be  more
       limited.   When color support is enabled, two colors are current at any
       given time: the [4mstroke[24m [4mcolor,[24m with which  glyphs,  rules  (lines),  and
       geometric  objects  like  circles  and polygons are drawn, and the [4mfill[0m
       [4mcolor,[24m which can be used to paint the interior of  a  closed  geometric
       figure.   The  [1mcolor[22m,  [1mdefcolor[22m, [1mgcolor[22m, and [1mfcolor [22mrequests; [1m\m [22mand [1m\M[0m
       escape sequences; and [1m.color[22m, [1m.m[22m, and [1m.M [22mregisters exercise color  sup‐
       port.

       Each  output  device has a color named “[1mdefault[22m”, which cannot be rede‐
       fined.  A device’s default stroke and fill colors are  not  necessarily
       the  same.  For the [1mdvi[22m, [1mhtml[22m, [1mpdf[22m, [1mps[22m, and [1mxhtml [22moutput devices, [4mtroff[0m
       automatically loads a macro file defining many color names at  startup.
       By the same mechanism, the devices supported by [4mgrotty[24m(1) recognize the
       eight  standard  ISO  6429/ECMA‐48  color names (also known vulgarly as
       “ANSI colors”).

[1mMeasurements[0m
       Numeric parameters that specify measurements are expressed as  integers
       or decimal fractions with an optional [4mscaling[24m [4munit[24m suffixed.  A scaling
       unit  is  a letter that immediately follows the last digit of a number.
       Digits after the decimal point are optional.

       Measurements are scaled by the scaling unit and stored internally (with
       any fractional part discarded) in basic units.  The  device  resolution
       can  therefore  be  obtained  by storing a value of “[1m1i[22m” to a register.
       The only constraint on the basic unit is that it is at least  as  small
       as any other unit.

       [1mu      [22mBasic unit.
       [1mi      [22mInch; defined as 2.54 centimeters.
       [1mc      [22mCentimeter.
       [1mp      [22mPoint;  a typesetter’s unit used for measuring type size.  There
              are 72 points to an inch.
       [1mP      [22mPica; another typesetter’s unit.  There are 6 picas to  an  inch
              and 12 points to a pica.
       [1ms[22m, [1mz   [22mScaled   points   and  multiplication  by  the  output  device’s
              [4msizescale[24m parameter, respectively.
       [1mf      [22mMultiplication by 65,536; scales decimal fractions in the inter‐
              val [0, 1] to 16‐bit unsigned integers.

       The magnitudes of other scaling units depend on the text formatting pa‐
       rameters in effect.

       [1mm      [22mEm; an em is equal to the current type size in points.
       [1mn      [22mEn; an en is one‐half em.
       [1mv      [22mVee; distance between text baselines.
       [1mM      [22mHundredth of an em.

   [1mMotion quanta[0m
       An output device’s basic unit [1mu [22mis not  necessarily  its  smallest  ad‐
       dressable  length;  [1mu  [22mcan  be  smaller  to avoid problems with integer
       roundoff.  The minimum distances that a device can  work  with  in  the
       horizontal and vertical directions are termed its [4mmotion[24m [4mquanta,[24m stored
       in  the [1m.H [22mand [1m.V [22mregisters, respectively.  Measurements are rounded to
       applicable motion quanta.  Half‐quantum fractions round toward zero.

   [1mDefault units[0m
       A general‐purpose register (one created or updated with the [1mnr [22mrequest;
       see section “Registers” below) is implicitly dimensionless, or reckoned
       in basic units if interpreted in a measurement context.  But it is con‐
       venient for many requests and escape sequences to infer a scaling  unit
       for  an  argument  if none is specified.  An explicit scaling unit (not
       after a closing parenthesis) can override an undesirable default.   Ef‐
       fectively,  the default unit is suffixed to the expression if a scaling
       unit is not already present.  GNU [4mtroff[24m’s  use  of  integer  arithmetic
       should also be kept in mind; see below.

[1mNumeric expressions[0m
       A  [4mnumeric[24m [4mexpression[24m evaluates to an integer.  The following operators
       are recognized.

             +   addition
             -   subtraction
             *   multiplication
             /   truncating division
             %   modulus
       ────────────────────────────────────────────
       unary +   assertion, motion, incrementation
       unary -   negation, motion, decrementation
       ────────────────────────────────────────────
             ;   scaling
            >?   maximum
            <?   minimum
       ────────────────────────────────────────────
             <   less than
             >   greater than
            <=   less than or equal
            >=   greater than or equal
             =   equal
            ==   equal
       ────────────────────────────────────────────
             &   logical conjunction (“and”)
             :   logical disjunction (“or”)
             !   logical complementation (“not”)
       ────────────────────────────────────────────
           ( )   precedence
       ────────────────────────────────────────────
             |   boundary‐relative motion

       [4mtroff[24m provides a set of mathematical and logical operators familiar  to
       programmers—as  well  as  some  unusual  ones—but supports only integer
       arithmetic.  (Provision is made for interpreting and reporting  decimal
       fractions in certain cases.)  The internal data type used for computing
       results is usually a 32‐bit signed integer, which suffices to represent
       magnitudes  within  a  range of ±2 billion.  (If that’s not enough, see
       [4mgroff_tmac[24m(5) for the [4m62bit.tmac[24m macro package.)

       Arithmetic infix operators perform a function on  the  numeric  expres‐
       sions  to their left and right; they are [1m+ [22m(addition), [1m- [22m(subtraction),
       [1m* [22m(multiplication), [1m/ [22m(truncating division), and [1m% [22m(modulus).  [4mTruncat‐[0m
       [4ming[24m [4mdivision[24m rounds to the integer nearer to zero, no matter how  large
       the fractional portion.  Overflow and division (or modulus) by zero are
       errors and abort evaluation of a numeric expression.

       Arithmetic  unary  operators operate on the numeric expression to their
       right; they are [1m- [22m(negation) and [1m+ [22m(assertion—for completeness; it does
       nothing).  The unary minus must often be used with parentheses to avoid
       confusion with the decrementation operator, discussed below.

       The sign of the modulus of operands of mixed signs is determined by the
       sign of the first.  Division and modulus operators satisfy the  follow‐
       ing  property:  given a dividend [4ma[24m and a divisor [4mb[24m, a quotient [4mq[24m formed
       by “[1m(a / b)[22m” and a remainder [4mr[24m by “[1m(a % b)[22m”, then [4mqb[24m + [4mr[24m = [4ma[24m.

       GNU [4mtroff[24m’s scaling operator, used with parentheses as [1m([4m[22mc[24m[1m;[4m[22me[24m[1m)[22m, evaluates
       a numeric expression [4me[24m using [4mc[24m as the default scaling unit.   If  [4mc[24m  is
       omitted,  scaling  units are ignored in the evaluation of [4me[24m.  GNU [4mtroff[0m
       also provides a pair  of  operators  to  compute  the  extrema  of  two
       operands: [1m>? [22m(maximum) and [1m<? [22m(minimum).

       Comparison operators comprise [1m< [22m(less than), [1m> [22m(greater than), [1m<= [22m(less
       than  or  equal),  [1m>=  [22m(greater than or equal), and [1m= [22m(equal).  [1m== [22mis a
       synonym for [1m=[22m.  When evaluated, a comparison is replaced with “[1m0[22m” if it
       is false and “[1m1[22m” if true.  In the [4mroff[24m language,  positive  values  are
       true, others false.

       We  can  operate  on truth values with the logical operators [1m& [22m(logical
       conjunction or “and”) and [1m: [22m(logical disjunction or “or”).  They evalu‐
       ate as comparison operators do.  A logical complementation (“not”)  op‐
       erator,  [1m!,  [22mworks  only within “[1mif[22m”, “[1mie[22m”, and “[1mwhile[22m” requests.  Fur‐
       thermore, [1m! [22mis recognized only at the beginning of a numeric expression
       not contained by another numeric expression.  In other words,  it  must
       be  the “outermost” operator.  Including it elsewhere in the expression
       produces a warning in the “[1mnumber[22m” category (see [4mtroff[24m(1)), and its ex‐
       pression evaluates false.  This unfortunate limitation  maintains  com‐
       patibility  with  AT&T [4mtroff[24m.  Test a numeric expression for falsity by
       comparing it to a false value.

       The [4mroff[24m language has no operator precedence: expressions are evaluated
       strictly from left to right, in  contrast  to  schoolhouse  arithmetic.
       Use parentheses [1m( ) [22mto impose a desired precedence upon subexpressions.

       For  many  requests and escape sequences that cause motion on the page,
       the unary operators [1m+ [22mand [1m- [22mwork differently when leading a numeric ex‐
       pression.  They then indicate a motion relative to  the  drawing  posi‐
       tion: positive is down in vertical contexts, right in horizontal ones.

       [1m+  [22mand [1m- [22mare also treated differently by the following requests and es‐
       cape sequences: [1mbp[22m, [1min[22m, [1mll[22m, [1mpl[22m, [1mpn[22m, [1mpo[22m, [1mps[22m, [1mpvs[22m, [1mrt[22m, [1mti[22m,  [1m\H[22m,  [1m\R[22m,  and
       [1m\s[22m.   Here,  leading  plus  and minus signs serve as incrementation and
       decrementation operators, respectively.  To negate an expression,  sub‐
       tract  it  from zero or include the unary minus in parentheses with its
       argument.

       A leading [1m| [22moperator indicates a motion relative not to the drawing po‐
       sition but to a boundary.   For  horizontal  motions,  the  measurement
       specifies  a  distance  relative to a drawing position corresponding to
       the beginning of the [4minput[24m line.  By default, tab  stops  reckon  move‐
       ments  in  this  way.  Most escape sequences do not; [1m| [22mtells them to do
       so.  For vertical motions, the [1m| [22moperator specifies a distance from the
       first text baseline on the page or in the current diversion, using  the
       current vertical spacing.

       The [1m\B [22mescape sequence tests its argument for validity as a numeric ex‐
       pression.

       A register interpolated as an operand in a numeric expression must have
       an Arabic format; luckily, this is the default.

       Due  to the way arguments are parsed, spaces are not allowed in numeric
       expressions unless the (sub)expression containing them is surrounded by
       parentheses.

[1mIdentifiers[0m
       An [4midentifier[24m labels a GNU [4mtroff[24m datum such as a register, name (macro,
       string, or diversion), typeface, color,  special  character,  character
       class,  environment,  or  stream.   Valid identifiers consist of one or
       more ordinary characters.  An [4mordinary[24m [4mcharacter[24m is an input  character
       that is not the escape character, a leader, tab, newline, or invalid as
       GNU [4mtroff[24m input.

       Invalid  input  characters  are  subset of control characters (from the
       sets “C0 Controls” and “C1 Controls” as Unicode describes them).   When
       [4mtroff[24m  encounters  one in an identifier, it produces a warning in cate‐
       gory “[1minput[22m” (see section “Warnings” in [4mtroff[24m(1)).   They  are  removed
       during  interpretation:  an  identifier  “foo”,  followed by an invalid
       character and then “bar”, is processed as “foobar”.

       On a machine using the ISO 646, 8859, or 10646 character encodings, in‐
       valid input characters are [1m0x00[22m, [1m0x08[22m, [1m0x0B[22m, [1m0x0D[22m–[1m0x1F[22m, and  [1m0x80[22m–[1m0x9F[22m.
       On  an  EBCDIC  host,  they are [1m0x00[22m–[1m0x01[22m, [1m0x08[22m, [1m0x09[22m, [1m0x0B[22m, [1m0x0D[22m–[1m0x14[22m,
       [1m0x17[22m–[1m0x1F[22m, and [1m0x30[22m–[1m0x3F[22m.  Some of these code points are used by  [4mtroff[0m
       internally, making it non‐trivial to extend the program to accept UTF‐8
       or other encodings that use characters from these ranges.

       An  identifier  with  a  closing bracket (“]”) in its name can’t be ac‐
       cessed with bracket‐form escape sequences that expect an identifier  as
       a  parameter.   Similarly, the identifier “(” can’t be interpolated [4mex‐[0m
       [4mcept[24m with bracket forms.

       If you begin a macro, string, or diversion  name  with  either  of  the
       characters  “[” or “]”, you foreclose use of the [4mrefer[24m(1) preprocessor,
       which recognizes “.[” and “.]” as bibliographic reference delimiters.

       The escape sequence [1m\A [22mtests its argument for validity  as  an  identi‐
       fier.

       How GNU [4mtroff[24m handles the interpretation of an undefined identifier de‐
       pends  on the context.  There is no way to invoke an undefined request;
       such syntax is interpreted as a macro call instead.  If the  identifier
       is  interpreted as a string, macro, or diversion, [4mtroff[24m emits a warning
       in category “[1mmac[22m”, defines it as empty, and interpolates  nothing.   If
       the  identifier  is interpreted as a register, [4mtroff[24m emits a warning in
       category “[1mreg[22m”, initializes it to zero, and  interpolates  that  value.
       See  section “Warnings” in [4mtroff[24m(1), and subsection “Interpolating reg‐
       isters” and section “Strings” below.  Attempting to  use  an  undefined
       typeface,  style,  special  character, color, character class, environ‐
       ment, or stream generally provokes an error diagnostic.

       Identifiers for requests, macros, strings,  and  diversions  share  one
       name space; special characters and character classes another.  No other
       object types do.

[1mControl characters[0m
       Control  characters  are  recognized  only at the beginning of an input
       line, or at the beginning of the branch of a control structure request;
       see section “Control structures” below.

       A few requests cause a break implicitly; use the no‐break control char‐
       acter to prevent the break.  Break suppression is its  sole  behavioral
       distinction.   Employing  the  no‐break control character to invoke re‐
       quests that don’t cause breaks is harmless but poor style.

       The control character “[1m.[22m” and the no‐break control character “[1m'[22m” can be
       changed with the [1mcc [22mand [1mc2 [22mrequests, respectively.  Within a macro def‐
       inition, register [1m.br [22mindicates the control character used to call it.

[1mInvoking requests[0m
       A control character is optionally followed by tabs  and/or  spaces  and
       then an identifier naming a request or macro.  The invocation of an un‐
       recognized  request  is  interpreted as a macro call.  Defining a macro
       with the same name as a request replaces the request.  Deleting  a  re‐
       quest  name  with the [1mrm [22mrequest makes it unavailable.  The [1mals [22mrequest
       can alias requests, permitting them to be wrapped or  non‐destructively
       replaced.  See section “Strings” below.

       There  is  no  inherent limit on argument length or quantity.  Most re‐
       quests take one or more arguments, and ignore any they do  not  expect.
       A  request  may  be separated from its arguments by tabs or spaces, but
       only spaces can separate an argument from its successor.  Only one  be‐
       tween  arguments  is  necessary; any excess is ignored.  GNU [4mtroff[24m does
       not allow tabs for argument separation.

       Generally, a space [4mwithin[24m a request argument is not relevant, not mean‐
       ingful, or is supported by bespoke provisions, as with the [1mtl [22mrequest’s
       delimiters.  Some requests, like [1mds[22m, interpret  the  remainder  of  the
       control line as a single argument.  See section “Strings” below.

       Spaces  and  tabs  immediately  after  a control character are ignored.
       Commonly, authors structure the source of documents or macro files with
       them.

[1mCalling macros[0m
       If a macro of the desired name does not exist when called, it  is  cre‐
       ated,  assigned an empty definition, and a warning in category “[1mmac[22m” is
       emitted.  Calling an undefined macro [4mdoes[24m end a macro definition naming
       it as its end macro (see section “Writing macros” below).

       To embed spaces [4mwithin[24m a macro argument, enclose the argument  in  neu‐
       tral  double  quotes ‘[1m"[22m’.  Horizontal motion escape sequences are some‐
       times a better choice for arguments to be formatted as text.

       The foregoing raises the question of how to embed neutral double quotes
       or backslashes in macro arguments when [4mthose[24m characters are desired  as
       literals.   In  GNU  [4mtroff[24m, the special character escape sequence [1m\[rs][0m
       produces a backslash and [1m\[dq] [22ma neutral double quote.

       In GNU [4mtroff[24m’s AT&T compatibility mode, these characters remain  avail‐
       able  as  [1m\(rs [22mand [1m\(dq[22m, respectively.  AT&T [4mtroff[24m did not consistently
       define these special characters, but its descendants  can  be  made  to
       support  them.   See  [4mgroff_font[24m(5).  If even that is not feasible, see
       the “Calling Macros” section of the [4mgroff[24m Texinfo manual for  the  com‐
       plex macro argument quoting rules of AT&T [4mtroff[24m.

[1mUsing escape sequences[0m
       Whereas  requests must occur on control lines, escape sequences can oc‐
       cur intermixed with text and  may  appear  in  arguments  to  requests,
       macros,  and  other escape sequences.  An escape sequence is introduced
       by the escape character, a backslash [1m\[22m.  The next character selects the
       escape’s function.

       Escape sequences vary in length.  Some take an argument, and of  those,
       some  have different syntactical forms for a one‐character, two‐charac‐
       ter, or arbitrary‐length argument.  Others accept  [4monly[24m  an  arbitrary‐
       length  argument.   In the former scheme, a one‐character argument fol‐
       lows the function character immediately, an opening parenthesis “[1m([22m” in‐
       troduces a two‐character argument (no closing parenthesis is used), and
       an argument of arbitrary length is enclosed in brackets “[1m[][22m”.   In  the
       latter  scheme,  the  user selects a delimiter character.  A few escape
       sequences are idiosyncratic, and support both of the foregoing  conven‐
       tions  ([1m\s[22m), designate their own termination sequence ([1m\?[22m), consume in‐
       put until the next newline ([1m\![22m, [1m\"[22m, [1m\#[22m), or support an additional modi‐
       fier character ([1m\s [22magain, and [1m\n[22m).

       If an escape character is followed by a character that does  not  iden‐
       tify  a defined operation, the escape character is ignored (producing a
       diagnostic of the “[1mescape[22m” warning category, which is  not  enabled  by
       default) and the following character is processed normally.

       Escape  sequence  interpolation is of higher precedence than escape se‐
       quence argument interpretation.  This rule affords flexibility in using
       escape sequences to construct parameters to other escape sequences.

       The escape character can be interpolated ([1m\e[22m).  Requests permit the es‐
       cape mechanism to be deactivated ([1meo[22m) and restored, or the escape char‐
       acter changed ([1mec[22m), and to save and restore it ([1mecs [22mand [1mecr[22m).

[1mDelimiters[0m
       Some escape sequences that require parameters use delimiters.  The neu‐
       tral apostrophe [1m' [22mis a popular choice and shown in this document.   The
       neutral  double  quote [1m" [22mis also commonly seen.  Letters, numerals, and
       leaders can be used.  Punctuation characters are likely better choices,
       except for those defined as infix operators in numeric expressions; see
       below.

       The following escape sequences don’t take arguments and  thus  are  al‐
       lowed  as  delimiters:  [1m\[4m[22mspace[24m, [1m\%[22m, [1m\|[22m, [1m\^[22m, [1m\{[22m, [1m\}[22m, [1m\'[22m, [1m\`[22m, [1m\-[22m, [1m\_[22m, [1m\![22m,
       [1m\?[22m, [1m\)[22m, [1m\/[22m, [1m\,[22m, [1m\&[22m, [1m\:[22m, [1m\~[22m, [1m\0[22m, [1m\a[22m, [1m\c[22m, [1m\d[22m, [1m\e[22m, [1m\E[22m, [1m\p[22m, [1m\r[22m, [1m\t[22m, and [1m\u[22m.
       However, using them this way is discouraged; they can  make  the  input
       confusing to read.

       A few escape sequences, [1m\A[22m, [1m\b[22m, [1m\o[22m, [1m\w[22m, [1m\X[22m, and [1m\Z[22m, accept a newline as
       a  delimiter.   Newlines that serve as delimiters continue to be recog‐
       nized as input line terminators.  Use of newlines as delimiters in  es‐
       cape sequences is also discouraged.

       Finally,  the  escape sequences [1m\D[22m, [1m\h[22m, [1m\H[22m, [1m\l[22m, [1m\L[22m, [1m\N[22m, [1m\R[22m, [1m\s[22m, [1m\S[22m, [1m\v[22m,
       and [1m\x [22mprohibit many delimiters.

              • the numerals 0–9 and the decimal point “[1m.[22m”

              • the (single‐character) operators [1m+-/*%<>=&:()[0m

              • any escape sequences other than [1m\%[22m, [1m\:[22m, [1m\{[22m, [1m\}[22m,  [1m\'[22m,  [1m\`[22m,  [1m\-[22m,
                [1m\_[22m, [1m\![22m, [1m\/[22m, [1m\c[22m, [1m\e[22m, and [1m\p[0m

       Delimiter  syntax is complex and flexible primarily for historical rea‐
       sons; the foregoing restrictions need be kept in mind mainly when using
       [4mgroff[24m in AT&T compatibility mode.  GNU [4mtroff[24m keeps track of the nesting
       depth of escape sequence interpolations, so  the  only  characters  you
       need  to  avoid  using as delimiters are those that appear in the argu‐
       ments you input, not any that result from interpolation.  Typically,  [1m'[0m
       works fine.  See section “Implementation differences” in [4mgroff_diff[24m(7).

[1mDummy characters[0m
       As  discussed  in  [4mroff[24m(7),  the  first  character  on an input line is
       treated specially.  Further, formatting a glyph has  many  consequences
       on  formatter  state (see section “Environments” below).  Occasionally,
       we want to escape this context or embrace some  of  those  consequences
       without  actually  rendering  a glyph to the output.  [1m\& [22minterpolates a
       dummy character, which is constitutive of output  but  invisible.   Its
       presence  alters the interpretation context of a subsequent input char‐
       acter, and enjoys several applications: preventing the insertion of ex‐
       tra space after an end‐of‐sentence character, preventing interpretation
       of a control character at the beginning of an  input  line,  preventing
       kerning  between  two  glyphs, and permitting the [1mtr [22mrequest to remap a
       character to “nothing”.  [1m\) [22mworks as [1m\& [22mdoes, except that it  does  not
       cancel a pending end‐of‐sentence state.

[1mControl structures[0m
       [4mgroff[24m  has  “if”  and  “while” control structures like other languages.
       However, the syntax for grouping multiple input lines in  the  branches
       or bodies of these structures is unusual.

       They  have  a  common form: the request name is (except for [1m.el [22m“else”)
       followed by a conditional expression [4mcond‐expr[24m; the  remainder  of  the
       line,  [4manything[24m, is interpreted as if it were an input line.  Any quan‐
       tity of spaces between arguments to requests serves  only  to  separate
       them;  leading spaces in [4manything[24m are therefore not seen.  [4manything[24m ef‐
       fectively [4mcannot[24m be omitted; if  [4mcond‐expr[24m  is  true  and  [4manything[24m  is
       empty,  the  newline at the end of the control line is interpreted as a
       blank line (and therefore a blank text line).

       It is frequently desirable for a control structure to govern more  than
       one  request, macro call, or text line, or a combination of the forego‐
       ing.  The opening and closing brace escape sequences [1m\{ [22mand [1m\}  [22mperform
       such  grouping.   Brace  escape sequences outside of control structures
       have no meaning and produce no output.

       [1m\{ [22mshould appear (after optional spaces and  tabs)  immediately  subse‐
       quent  to  the request’s conditional expression.  [1m\} [22mshould appear on a
       line with other occurrences of itself as  necessary  to  match  [1m\{  [22mse‐
       quences.   It can be preceded by a control character, spaces, and tabs.
       Input after any quantity of [1m\} [22msequences on the same line is  processed
       only if all the preceding conditions to which they correspond are true.
       Furthermore, a [1m\} [22mclosing the body of a [1m.while [22mrequest must be the last
       such escape sequence on an input line.

   [1mConditional expressions[0m
       The  [1m.if[22m, [1m.ie[22m, and [1m.while [22mrequests test the truth values of numeric ex‐
       pressions.  They also support several additional Boolean operators; the
       members of this expanded  class  are  termed  [4mconditional[24m  [4mexpressions[24m;
       their truth values are as shown below.

       [4m[1mcond‐expr[24m[22m...   [1m...is true if...[0m
       ────────────────────────────────────────────────────────────────────────
            [1m'[4m[22ms1[24m[1m'[4m[22ms2[24m[1m'   [4m[22ms1[24m produces the same formatted output as [4ms2[24m.
                [1mc [4m[22mg[24m   a glyph [4mg[24m is available.
                [1md [4m[22mm[24m   a string, macro, diversion, or request [4mm[24m is defined.
                  [1me   [22mthe current page number is even.
                [1mF [4m[22mf[24m   a font named [4mf[24m is available.
                [1mm [4m[22mc[24m   a color named [4mc[24m is defined.
                  [1mn   [22mthe formatter is in [4mnroff[24m mode.
                  [1mo   [22mthe current page number is odd.
                [1mr [4m[22mn[24m   a register named [4mn[24m is defined.
                [1mS [4m[22ms[24m   a font style named [4ms[24m is available.
                  [1mt   [22mthe formatter is in [4mtroff[24m mode.
                  [1mv   [22mn/a (historical artifact; always false).

       If  the  first argument to an [1m.if[22m, [1m.ie[22m, or [1m.while [22mrequest begins with a
       non‐alphanumeric character apart from [1m! [22m(see  below);  it  performs  an
       [4moutput[24m  [4mcomparison[24m  [4mtest.[24m   Shown  first in the table above, the [4moutput[0m
       [4mcomparison[24m [4moperator[24m interpolates a true value if  formatting  its  com‐
       parands  [4ms1[24m and [4ms2[24m produces the same output commands.  Other delimiters
       can be used in place of the neutral apostrophes.  [4mtroff[24m formats [4ms1[24m  and
       [4ms2[24m  in  separate environments; after the comparison, the resulting data
       are discarded.  The resulting glyph properties, including font  family,
       style,  size,  and  slant, must match, but not necessarily the requests
       and/or escape sequences used to obtain them.   Motions  must  match  in
       orientation and magnitude to within the applicable horizontal or verti‐
       cal motion quantum of the device, after rounding.

       Surround  the  comparands with [1m\? [22mto avoid formatting them; this causes
       them to be compared character by character, as with string  comparisons
       in other programming languages.  Since comparands protected with [1m\? [22mare
       read  in  copy mode, they need not even be valid [4mgroff[24m syntax.  The es‐
       cape character is still lexically recognized, however, and consumes the
       next character.

       The above operators can’t be combined with most others, but  a  leading
       “[1m![22m”, not followed immediately by spaces or tabs, complements an expres‐
       sion.   Spaces  and  tabs  are optional immediately after the “[1mc[22m”, “[1md[22m”,
       “[1mF[22m”, “[1mm[22m”, “[1mr[22m”, and “[1mS[22m” operators, but right after  “[1m![22m”,  they  end  the
       predicate  and  the conditional evaluates true.  (This bizarre behavior
       maintains compatibility with AT&T [4mtroff[24m.)

[1mSyntax reference conventions[0m
       In the following request and escape sequence specifications, most argu‐
       ment names were chosen to be descriptive.  A few  denotations  may  re‐
       quire introduction.

              [4mc[24m         denotes a single input character.
              [4mfont[24m      a  font  either  specified as a font name or a numeric
                        mounting position.
              [4manything[24m  all characters up to the end of the line, to the  end‐
                        ing  delimiter  for  the escape sequence, or within [1m\{[0m
                        and [1m\}[22m.  Escape sequences may generally be used freely
                        in [4manything[24m, except when it is read in copy mode.
              [4mmessage[24m   is a character sequence to be emitted on the  standard
                        error  stream.  Special character escape sequences are
                        [4mnot[24m interpreted.
              [4mn[24m         is a numeric expression that evaluates to a  non‐nega‐
                        tive integer.
              [4mnpl[24m       is a numeric expression constituting a count of subse‐
                        quent  [4mproductive[24m input lines; that is, those that di‐
                        rectly produce formatted output.  Text  lines  produce
                        output,  as  do control lines containing requests like
                        [1m.tl [22mor escape sequences like [1m\D[22m.  Macro calls are  not
                        themselves productive, but their interpolated contents
                        can be.
              [4m±N[24m        is  a  numeric  expression with a meaning dependent on
                        its sign.

       If a numeric expression presented as [4m±N[24m starts with a ‘[1m+[22m’ sign, an  in‐
       crement in the amount of of [4mN[24m is applied to the value applicable to the
       request  or escape sequence.  If it starts with a ‘[1m-[22m’ sign, a decrement
       of magnitude [4mN[24m is applied instead.  Without a sign, [4mN[24m replaces any  ex‐
       isting  value.   A  leading  minus sign in [4mN[24m is always interpreted as a
       decrementation operator, not an algebraic sign.  To assign a register a
       negative value or the negated value of  another  register,  enclose  it
       with  its  operand in parentheses or subtract it from zero.  If a prior
       value does not exist (the register  was  undefined),  an  increment  or
       decrement is applied as if to 0.

[1mRequest short reference[0m
       Not  all  details of request behavior are outlined here.  See the [4mgroff[0m
       Texinfo manual or, for features new to GNU [4mtroff[24m, [4mgroff_diff[24m(7).

       [1m.ab       [22mAbort processing; exit with failure status.
       [1m.ab [4m[22mmessage[0m
                 Abort processing; write [4mmessage[24m to the standard error  stream
                 and exit with failure status.
       [1m.ad       [22mEnable  output  line  alignment and adjustment using the mode
                 stored in [1m\n[.j][22m.
       [1m.ad [4m[22mc[24m     Enable  output  line  alignment  and  adjustment  in  mode  [4mc[0m
                 ([4mc[24m=[1mb[22m,[1mc[22m,[1ml[22m,[1mn[22m,[1mr[22m).  Sets [1m\n[.j][22m.
       [1m.af [4m[22mregister[24m [4mc[0m
                 Assign  format  [4mc[24m to [4mregister[24m, where [4mc[24m is “[1mi[22m”, “[1mI[22m”, “[1ma[22m”, “[1mA[22m”,
                 or a sequence of decimal digits whose  quantity  denotes  the
                 minimum  width  in digits to be used when the register is in‐
                 terpolated.  “[1mi[22m” and “[1ma[22m” indicate Roman  numerals  and  basic
                 Latin alphabetics, respectively, in the lettercase specified.
                 The default is [1m0[22m.
       [1m.aln [4m[22mnew[24m [4mold[0m
                 Create  alias  (additional  name)  [4mnew[24m  for existing register
                 named [4mold[24m.
       [1m.als [4m[22mnew[24m [4mold[0m
                 Create alias (additional  name)  [4mnew[24m  for  existing  request,
                 string, macro, or diversion [4mold[24m.
       [1m.am [4m[22mmacro[24m Append to [4mmacro[24m until [1m.. [22mis encountered.
       [1m.am [4m[22mmacro[24m [4mend[0m
                 Append to [4mmacro[24m until [1m.[4m[22mend[24m is called.
       [1m.am1 [4m[22mmacro[0m
                 Same  as  [1m.am [22mbut with compatibility mode switched off during
                 macro expansion.
       [1m.am1 [4m[22mmacro[24m [4mend[0m
                 Same as [1m.am [22mbut with compatibility mode switched  off  during
                 macro expansion.
       [1m.ami [4m[22mmacro[0m
                 Append to a macro whose name is contained in the string [4mmacro[0m
                 until [1m.. [22mis encountered.
       [1m.ami [4m[22mmacro[24m [4mend[0m
                 Append  to  a  macro  indirectly.   [4mmacro[24m and [4mend[24m are strings
                 whose contents are interpolated for the macro  name  and  the
                 end macro, respectively.
       [1m.ami1 [4m[22mmacro[0m
                 Same  as [1m.ami [22mbut with compatibility mode switched off during
                 macro expansion.
       [1m.ami1 [4m[22mmacro[24m [4mend[0m
                 Same as [1m.ami [22mbut with compatibility mode switched off  during
                 macro expansion.
       [1m.as [4m[22mname[24m  Create  string [4mname[24m with empty contents; no operation if [4mname[0m
                 already exists.
       [1m.as [4m[22mname[24m [4mcontents[0m
                 Append [4mcontents[24m to string [4mname[24m.
       [1m.as1 [4m[22mstring[0m
       [1m.as1 [4m[22mstring[24m [4mcontents[0m
                 As [1m.as[22m, but with compatibility mode  disabled  when  [4mcontents[0m
                 interpolated.
       [1m.asciify [4m[22mdiversion[0m
                 Unformat  ASCII characters, spaces, and some escape sequences
                 in [4mdiversion[24m.
       [1m.backtrace[0m
                 Write the state of the input  stack  to  the  standard  error
                 stream.  See the [1m-b [22moption of [4mgroff[24m(1).
       [1m.bd [4m[22mfont[24m  Stop emboldening font [4mfont.[0m
       [1m.bd [4m[22mfont[24m [4mn[0m
                 Embolden [4mfont[24m by overstriking its glyphs offset by [4mn[24m-1 units.
                 See register [1m.b[22m.
       [1m.bd [4m[22mspecial‐font[24m [4mfont[0m
                 Stop emboldening [4mspecial‐font[24m when [4mfont[24m is selected.
       [1m.bd [4m[22mspecial‐font[24m [4mfont[24m [4mn[0m
                 Embolden  [4mspecial‐font,[24m overstriking its glyphs offset by [4mn[24m-1
                 units when [4mfont[24m is selected.  See register [1m.b[22m.
       [1m.blm      [22mUnset blank line macro (trap).  Restore default  handling  of
                 blank lines.
       [1m.blm [4m[22mname[24m Set blank line macro (trap) to [4mname[24m.
       [1m.box      [22mStop  directing output to current diversion; any pending out‐
                 put line is discarded.
       [1m.box [4m[22mname[24m Direct output to diversion [4mname[24m, omitting  a  partially  col‐
                 lected line.
       [1m.boxa     [22mStop  appending output to current diversion; any pending out‐
                 put line is discarded.
       [1m.boxa [4m[22mname[0m
                 Append output to diversion [4mname[24m, omitting  a  partially  col‐
                 lected line.
       [1m.bp       [22mBreak page and start a new one.
       [1m.bp [4m[22m±N[24m    Break page, starting a new one numbered [4m±N[24m.
       [1m.br       [22mBreak output line.
       [1m.brp      [22mBreak output line; adjust if applicable.
       [1m.break    [22mBreak out of a while loop.
       [1m.c2       [22mReset no‐break control character to “[1m'[22m”.
       [1m.c2 [4m[22mo[24m     Recognize ordinary character [4mo[24m as no‐break control character.
       [1m.cc       [22mReset control character to ‘[1m.[22m’.
       [1m.cc [4m[22mo[24m     Recognize ordinary character [4mo[24m as the control character.
       [1m.ce       [22mBreak,  center  the  output of the next productive input line
                 without filling, and break again.
       [1m.ce [4m[22mnpl[24m   Break, center the output of the  next  [4mnpl[24m  productive  input
                 lines  without  filling,  then break again.  If [4mnpl[24m ≤ 0, stop
                 centering.
       [1m.cf [4m[22mfile[24m  Copy contents of [4mfile[24m without formatting to  the  (top‐level)
                 diversion.
       [1m.cflags [4m[22mn[24m [4mc1[24m [4mc2[24m ...
                 Assign  properties  encoded by [4mn[24m to characters [4mc1[24m, [4mc2[24m, and so
                 on.
       [1m.ch [4m[22mname[24m  Unplant page location trap [4mname[24m.
       [1m.ch [4m[22mname[24m [4mvpos[0m
                 Change page location trap [4mname[24m planted by [1m.wh [22mby  moving  its
                 location to [4mvpos[24m (default scaling unit [1mv[22m).
       [1m.char [4m[22mc[24m [4mcontents[0m
                 Define ordinary or special character [4mc[24m as [4mcontents[24m.
       [1m.chop [4m[22mobject[0m
                 Remove  the  last character from the macro, string, or diver‐
                 sion named [4mobject[24m.
       [1m.class [4m[22mname[24m [4mc1[24m [4mc2[24m ...
                 Define a (character) class [4mname[24m comprising the characters  or
                 range expressions [4mc1[24m, [4mc2[24m, and so on.
       [1m.close [4m[22mstream[0m
                 Close the [4mstream[24m.
       [1m.color    [22mEnable output of color‐related device‐independent output com‐
                 mands.
       [1m.color [4m[22mn[24m  If [4mn[24m is zero, disable output of color‐related device‐indepen‐
                 dent output commands; otherwise, enable them.
       [1m.composite [4m[22mfrom[24m [4mto[0m
                 Map  glyph  name  [4mfrom[24m  to glyph name [4mto[24m while constructing a
                 composite glyph name.
       [1m.continue [22mFinish the current iteration of a while loop.
       [1m.cp       [22mEnable compatibility mode.
       [1m.cp [4m[22mn[24m     If [4mn[24m is zero, disable compatibility  mode,  otherwise  enable
                 it.
       [1m.cs [4m[22mfont[24m [4mn[24m [4mm[0m
                 Set  constant  character width mode for [4mfont[24m to [4mn[24m/36 ems with
                 em [4mm[24m.
       [1m.cu       [22mContinuously underline the output of the next productive  in‐
                 put line.
       [1m.cu [4m[22mnpl[24m   Continuously  underline the output of the next [4mnpl[24m productive
                 input lines.  If [4mnpl[24m=0, stop continuously underlining.
       [1m.da       [22mStop appending output to current diversion.
       [1m.da [4m[22mname[24m  Append output to diversion [4mname[24m.
       [1m.de [4m[22mmacro[24m Define or redefine [4mmacro[24m until “[1m..[22m” occurs at the start of  a
                 control line in the current conditional block.
       [1m.de [4m[22mmacro[24m [4mend[0m
                 Define  or  redefine  [4mmacro[24m until [4mend[24m is invoked or called at
                 the start of a control line in the current conditional block.
       [1m.de1 [4m[22mmacro[0m
                 As [1m.de[22m, but disable compatibility mode  during  macro  expan‐
                 sion.
       [1m.de1 [4m[22mmacro[24m [4mend[0m
                 As  “[1m.de  [4m[22mmacro[24m  [4mend[24m”,  but disable compatibility mode during
                 macro expansion.
       [1m.defcolor [4m[22mident[24m [4mscheme[24m [4mcolor‐component[24m ...
                 Define a color named [4mident.[24m  [4mscheme[24m identifies a color  space
                 and  determines  the  number of required [4mcolor‐component[24ms; it
                 must be one  of  “[1mrgb[22m”  (three  components),  “[1mcmy[22m”  (three),
                 “[1mcmyk[22m” (four), or “[1mgray[22m” (one).  “[1mgrey[22m” is accepted as a syn‐
                 onym  of  “[1mgray[22m”.   The  color components can be encoded as a
                 single hexadecimal value starting with [1m# [22mor [1m##[22m.   The  former
                 indicates  that  each component is in the range 0–255 (0–FF),
                 the latter the range 0–65,535 (0–FFFF).  Alternatively,  each
                 color component can be specified as a decimal fraction in the
                 range  0–1,  interpreted using a default scaling unit of “[1mf[22m”,
                 which multiplies its  value  by  65,536  (but  clamps  it  at
                 65,535).   Each  output  device  has a color named “[1mdefault[22m”,
                 which cannot be redefined.  A  device’s  default  stroke  and
                 fill colors are not necessarily the same.
       [1m.dei [4m[22mmacro[0m
                 Define  macro  indirectly.   As [1m.de[22m, but use interpolation of
                 string [4mmacro[24m as the name of the defined macro.
       [1m.dei [4m[22mmacro[24m [4mend[0m
                 Define macro indirectly.  As [1m.de[22m, but use  interpolations  of
                 strings  [4mmacro[24m  and  [4mend[24m  as the names of the defined and end
                 macros.
       [1m.dei1 [4m[22mmacro[0m
                 As [1m.dei[22m, but disable compatibility mode during  macro  expan‐
                 sion.
       [1m.dei1 [4m[22mmacro[24m [4mend[0m
                 As  [1m.dei  [4m[22mmacro[24m  [4mend[24m,  but  disable compatibility mode during
                 macro expansion.
       [1m.device [4m[22manything[0m
                 Write [4manything[24m, read in copy mode, to [4mtroff[24m output as  a  de‐
                 vice  control  command.   An  initial neutral double quote is
                 stripped to allow embedding of leading spaces.
       [1m.devicem [4m[22mname[0m
                 Write contents of macro or string [4mname[24m to [4mtroff[24m output  as  a
                 device control command.
       [1m.di       [22mStop directing output to current diversion.
       [1m.di [4m[22mname[24m  Direct output to diversion [4mname[24m.
       [1m.do [4m[22mname[24m ...
                 Interpret  the  string,  request,  diversion,  or  macro [4mname[0m
                 (along with any arguments) with compatibility mode  disabled.
                 Compatibility  mode  is restored (only if it was active) when
                 the [4mexpansion[24m of [4mname[24m is interpreted.
       [1m.ds [4m[22mname[24m  Create empty string [4mname[24m.
       [1m.ds [4m[22mname[24m [4mcontents[0m
                 Create a string [4mname[24m containing [4mcontents[24m.
       [1m.ds1 [4m[22mname[0m
       [1m.ds1 [4m[22mname[24m [4mcontents[0m
                 As [1m.ds[22m, but with compatibility mode  disabled  when  [4mcontents[0m
                 interpolated.
       [1m.dt       [22mClear diversion trap.
       [1m.dt [4m[22mvertical‐position[24m [4mname[0m
                 Set  the  diversion  trap  to macro [4mname[24m at [4mvertical‐position[0m
                 (default scaling unit [1mv[22m).
       [1m.ec       [22mRecognize [1m\ [22mas the escape character.
       [1m.ec [4m[22mo[24m     Recognize ordinary character [4mo[24m as the escape character.
       [1m.ecr      [22mRestore escape character saved with [1m.ecs[22m.
       [1m.ecs      [22mSave the escape character.
       [1m.el [4m[22manything[0m
                 Interpret [4manything[24m as if it were an input line if the  condi‐
                 tional expression of the corresponding [1m.ie [22mrequest was false.
       [1m.em [4m[22mname[24m  Call macro [4mname[24m after the end of input.
       [1m.eo       [22mDisable the escape mechanism in interpretation mode.
       [1m.ev       [22mPop environment stack, returning to previous one.
       [1m.ev [4m[22menv[24m   Push current environment onto stack and switch to [4menv[24m.
       [1m.evc [4m[22menv[24m  Copy environment [4menv[24m to the current one.
       [1m.ex       [22mExit with successful status.
       [1m.fam      [22mSet default font family to previous value.
       [1m.fam [4m[22mname[24m Set default font family to [4mname[24m.
       [1m.fc       [22mDisable field mechanism.
       [1m.fc [4m[22ma[24m     Set field delimiter to [4ma[24m and pad glyph to space.
       [1m.fc [4m[22ma[24m [4mb[24m   Set field delimiter to [4ma[24m and pad glyph to [4mb[24m.
       [1m.fchar [4m[22mc[24m [4mcontents[0m
                 Define fallback character (or glyph) [4mc[24m as [4mcontents[24m.
       [1m.fcolor   [22mRestore previous fill color.
       [1m.fcolor [4m[22mc[24m Set fill color to [4mc[24m.
       [1m.fi       [22mEnable filling of output lines; a pending output line is bro‐
                 ken.  Sets [1m\n[.u][22m.
       [1m.fl       [22mFlush output buffer.
       [1m.fp [4m[22mpos[24m [4mid[0m
                 Mount font with font description file name [4mid[24m at non‐negative
                 position [4mn[24m.
       [1m.fp [4m[22mpos[24m [4mid[24m [4mfont‐description‐file‐name[0m
                 Mount font with [4mfont‐description‐file‐name[24m as name [4mid[24m at non‐
                 negative position [4mn[24m.
       [1m.fschar [4m[22mf[24m [4mc[24m [4manything[0m
                 Define  fallback  character (or glyph) [4mc[24m for font [4mf[24m as string
                 [4manything[24m.
       [1m.fspecial [4m[22mfont[0m
                 Reset list of special fonts for [4mfont[24m to be empty.
       [1m.fspecial [4m[22mfont[24m [4ms1[24m [4ms2[24m ...
                 When the current font is [4mfont[24m, then the fonts [4ms1[24m, [4ms2[24m, ... are
                 special.
       [1m.ft[0m
       [1m.ft P     [22mSelect previous font mounting  position  (abstract  style  or
                 font); same as [1m\f[] [22mor [1m\fP[22m.
       [1m.ft [4m[22mfont[24m  Select  typeface  [4mfont,[24m which can be a mounting position, ab‐
                 stract style, or font name; same as [1m\f[[4m[22mfont[24m[1m] [22mescape sequence.
                 [4mfont[24m cannot be [1mP[22m.
       [1m.ftr [4m[22mfont1[24m [4mfont2[0m
                 Translate [4mfont1[24m to [4mfont2[24m.
       [1m.fzoom [4m[22mfont[0m
       [1m.fzoom [4m[22mfont[24m [1m0[0m
                 Stop magnifying [4mfont[24m.
       [1m.fzoom [4m[22mfont[24m [4mz[0m
                 Set zoom factor for  [4mfont[24m  to  [4mz[24m  (in  thousandths;  default:
                 1000).
       [1m.gcolor   [22mRestore previous stroke color.
       [1m.gcolor [4m[22mc[24m Set stroke color to [4mc[24m.
       [1m.hc       [22mReset the hyphenation character to [1m\% [22m(the default).
       [1m.hc [4m[22mchar[24m  Change the hyphenation character to [4mchar[24m.
       [1m.hcode [4m[22mc1[24m [4mcode1[24m [[4mc2[24m [4mcode2[24m] ...
                 Set the hyphenation code of character [4mc1[24m to [4mcode1[24m, that of [4mc2[0m
                 to [4mcode2[24m, and so on.
       [1m.hla [4m[22mlang[24m Set the hyphenation language to [4mlang[24m.
       [1m.hlm [4m[22mn[24m    Set  the  maximum quantity of consecutive hyphenated lines to
                 [4mn[24m.
       [1m.hpf [4m[22mpattern‐file[0m
                 Read hyphenation patterns from [4mpattern‐file[24m.
       [1m.hpfa [4m[22mpattern‐file[0m
                 Append hyphenation patterns from [4mpattern‐file[24m.
       [1m.hpfcode [4m[22ma[24m [4mb[24m [[4mc[24m [4md[24m] ...
                 Define mappings for character codes  in  hyphenation  pattern
                 files read with [1m.hpf [22mand [1m.hpfa[22m.
       [1m.hw [4m[22mword[24m ...
                 Define  hyphenation overrides for each [4mword;[24m a hyphen “[1m-[22m” in‐
                 dicates a hyphenation point.
       [1m.hy       [22mSet automatic hyphenation mode to [1m1[22m.
       [1m.hy 0     [22mDisable automatic hyphenation; same as [1m.nh[22m.
       [1m.hy [4m[22mmode[24m  Set automatic hyphenation mode to [4mmode[24m; see section  “Hyphen‐
                 ation” below.
       [1m.hym      [22mSet the (right) hyphenation margin to [1m0 [22m(the default).
       [1m.hym [4m[22mlength[0m
                 Set the (right) hyphenation margin to [4mlength[24m (default scaling
                 unit [1mm[22m).
       [1m.hys      [22mSet the hyphenation space to [1m0 [22m(the default).
       [1m.hys [4m[22mhyphenation‐space[0m
                 Suppress automatic hyphenation in adjustment modes “[1mb[22m” or “[1mn[22m”
                 if  the  line can be justified with the addition of up to [4mhy‐[0m
                 [4mphenation‐space[24m to each  inter‐word  space  (default  scaling
                 unit [1mm[22m).
       [1m.ie [4m[22mcond‐expr[24m [4manything[0m
                 If [4mcond‐expr[24m is true, interpret [4manything[24m as if it were an in‐
                 put line, otherwise skip to a corresponding [1m.el [22mrequest.
       [1m.if [4m[22mcond‐expr[24m [4manything[0m
                 If  [4mcond‐expr[24m  is true, then interpret [4manything[24m as if it were
                 an input line.
       [1m.ig       [22mIgnore input (except for side effects of  [1m\R  [22mon  auto‐incre‐
                 menting  registers)  until “[1m..[22m” occurs at the start of a con‐
                 trol line in the current conditional block.
       [1m.ig [4m[22mend[24m   Ignore input (except for side effects of  [1m\R  [22mon  auto‐incre‐
                 menting  registers)  until  [1m.[4m[22mend[24m  is called at the start of a
                 control line in the current conditional block.
       [1m.in       [22mSet indentation amount to previous value.
       [1m.in [4m[22m±N[24m    Set indentation to [4m±N[24m (default scaling unit [1mm[22m).
       [1m.it       [22mCancel any pending input line trap.
       [1m.it [4m[22mnpl[24m [4mname[0m
                 Set (or replace) an input line trap in the environment, call‐
                 ing macro [4mname[24m, after the next  [4mnpl[24m  productive  input  lines
                 have  been  read.   Lines  interrupted with the [1m\c [22mescape se‐
                 quence are counted separately.
       [1m.itc      [22mCancel any pending input line trap.
       [1m.itc [4m[22mnpl[24m [4mname[0m
                 As [1m.it[22m, except that input lines interrupted with the  [1m\c  [22mes‐
                 cape sequence are not counted.
       [1m.kern     [22mEnable pairwise kerning.
       [1m.kern [4m[22mn[24m   If [4mn[24m is zero, disable pairwise kerning, otherwise enable it.
       [1m.lc       [22mUnset leader repetition character.
       [1m.lc [4m[22mc[24m     Set leader repetition character to [4mc[24m (default: “[1m.[22m”).
       [1m.length [4m[22mreg[24m [4manything[0m
                 Compute  the  number  of characters of [4manything[24m and store the
                 count in the register [4mreg[24m.
       [1m.linetabs [22mEnable line‐tabs mode (calculate tab  positions  relative  to
                 beginning of output line).
       [1m.linetabs 0[0m
                 Disable line‐tabs mode.
       [1m.lf [4m[22mn[24m     Set number of next input line to [4mn[24m.
       [1m.lf [4m[22mn[24m [4mfile[0m
                 Set  number  of  next  input line to [4mn[24m and input file name to
                 [4mfile[24m.
       [1m.lg [4m[22mm[24m     Set ligature mode to [4mm[24m ([1m0 [22m= disable, [1m1 [22m= enable, [1m2  [22m=  enable
                 for two‐letter ligatures only).
       [1m.ll       [22mSet line length to previous value.  Does not affect a pending
                 output line.
       [1m.ll [4m[22m±N[24m    Set  line  length to [4m±N[24m (default length 6.5[1mi[22m, default scaling
                 unit [1mm[22m).  Does not affect a pending output line.
       [1m.lsm      [22mUnset the leading space macro (trap).  Restore  default  han‐
                 dling of lines with leading spaces.
       [1m.lsm [4m[22mname[24m Set the leading space macro (trap) to [4mname[24m.
       [1m.ls       [22mChange to the previous value of additional intra‐line skip.
       [1m.ls [4m[22mn[24m     Set  additional  intra‐line  skip value to [4mn[24m, i.e., [4mn[24m-1 blank
                 lines are inserted after each text output line.
       [1m.lt       [22mSet length of title lines to previous value.
       [1m.lt [4m[22m±N[24m    Set length of title lines (default length 6.5[1mi[22m, default scal‐
                 ing unit [1mm[22m).
       [1m.mc       [22mCease writing margin character.
       [1m.mc [4m[22mc[24m     Begin writing margin character [4mc[24m to the right of each  output
                 line.
       [1m.mc [4m[22mc[24m [4md[24m   Begin  writing margin character [4mc[24m on each output line at dis‐
                 tance [4md[24m to the right of the right  margin  (default  distance
                 10[1mp[22m, default scaling unit [1mm[22m).
       [1m.mk       [22mMark  vertical  drawing position in an internal register; see
                 [1m.rt[22m.
       [1m.mk [4m[22mregister[0m
                 Mark vertical drawing position in [4mregister[24m.
       [1m.mso [4m[22mfile[24m As [1m.so[22m, except that [4mfile[24m is sought in the [4mtmac[24m directories.
       [1m.msoquiet [4m[22mfile[0m
                 As [1m.mso[22m, but no warning is emitted if [4mfile[24m does not exist.
       [1m.na       [22mDisable output line adjustment.
       [1m.ne       [22mBreak page if distance to next page  location  trap  is  less
                 than one vee.
       [1m.ne [4m[22md[24m     Break  page  if  distance  to next page location trap is less
                 than distance [4md[24m (default scaling unit [1mv[22m).
       [1m.nf       [22mDisable filling of output lines; a  pending  output  line  is
                 broken.  Clears [1m\n[.u][22m.
       [1m.nh       [22mDisable automatic hyphenation; same as “[1m.hy 0[22m”.
       [1m.nm       [22mDeactivate output line numbering.
       [1m.nm [4m[22m±N[0m
       [1m.nm [4m[22m±N[24m [4mm[0m
       [1m.nm [4m[22m±N[24m [4mm[24m [4ms[0m
       [1m.nm [4m[22m±N[24m [4mm[24m [4ms[24m [4mi[0m
                 Activate  output  line numbering: number the next output line
                 [4m±N,[24m writing numbers every [4mm[24m lines, with [4ms[24m numeral widths ([1m\0[22m)
                 between the line number and the output (default 1),  and  in‐
                 denting the line number by [4mi[24m numeral widths (default 0).
       [1m.nn       [22mSuppress  numbering  of  the  next output line to be numbered
                 with [1mnm[22m.
       [1m.nn [4m[22mn[24m     Suppress numbering of the next [4mn[24m output lines to be  numbered
                 with [1mnm[22m.  If [4mn[24m=0, cancel suppression.
       [1m.nop [4m[22manything[0m
                 Interpret [4manything[24m as if it were an input line.
       [1m.nr [4m[22mreg[24m [4m±N[0m
                 Define or update register [4mreg[24m with value [4mN[24m.
       [1m.nr [4m[22mreg[24m [4m±N[24m [4mI[0m
                 Define or update register [4mreg[24m with value [4mN[24m and auto‐increment
                 [4mI[24m.
       [1m.nroff    [22mMake the conditional expressions [1mn [22mtrue and [1mt [22mfalse.
       [1m.ns       [22mEnable  [4mno‐space[24m [4mmode[24m, ignoring [1m.sp [22mrequests until a glyph or
                 [1m\D [22mprimitive is output.  See [1m.rs[22m.
       [1m.nx       [22mImmediately jump to end of current file.
       [1m.nx [4m[22mfile[24m  Stop formatting current file and begin reading [4mfile.[0m
       [1m.open [4m[22mstream[24m [4mfile[0m
                 Open [4mfile[24m for writing and associate the stream  named  [4mstream[0m
                 with it.  Unsafe request; disabled by default.
       [1m.opena [4m[22mstream[24m [4mfile[0m
                 As  [1m.open[22m,  but  append to [4mfile.[24m  Unsafe request; disabled by
                 default.
       [1m.os       [22mOutput vertical distance that was saved by the [1m.sv [22mrequest.
       [1m.output [4m[22mcontents[0m
                 Emit [4mcontents[24m directly to intermediate output, allowing lead‐
                 ing whitespace if [4mstring[24m starts with  [1m"  [22m(which  is  stripped
                 off).
       [1m.pc       [22mReset page number character to ‘[1m%[22m’.
       [1m.pc [4m[22mc[24m     Page number character.
       [1m.pev      [22mReport  the state of the current environment followed by that
                 of all other environments to the standard error stream.
       [1m.pi [4m[22mprogram[0m
                 Pipe output to [4mprogram[24m ([4mnroff[24m only).   Unsafe  request;  dis‐
                 abled by default.
       [1m.pl       [22mSet  page  length to default 11[1mi[22m.  The current page length is
                 stored in register [1m.p[22m.
       [1m.pl [4m[22m±N[24m    Change page length to [4m±N[24m (default scaling unit [1mv[22m).
       [1m.pm       [22mReport, to the standard error stream, the names and sizes  in
                 bytes of defined macros, strings, and diversions.
       [1m.pn [4m[22m±N[24m    Next page number [4mN[24m.
       [1m.pnr      [22mWrite  the names and contents of all defined registers to the
                 standard error stream.
       [1m.po       [22mChange to previous page offset.  The current page  offset  is
                 available in register [1m.o[22m.
       [1m.po [4m[22m±N[24m    Page offset [4mN[24m.
       [1m.ps       [22mReturn to previous type size.
       [1m.ps [4m[22m±N[24m    Set/increase/decrease  the type size to/by [4mN[24m scaled points (a
                 non‐positive resulting type size is set to  1  u);  also  see
                 [1m\s[[4m[22m±N[24m[1m][22m.
       [1m.psbb [4m[22mfile[0m
                 Retrieve  the  bounding  box of the PostScript image found in
                 [4mfile,[24m which must conform to Adobe’s Document Structuring Con‐
                 ventions (DSC).  See registers [1mllx[22m, [1mlly[22m, [1murx[22m, [1mury[22m.
       [1m.pso [4m[22mcommand‐line[0m
                 Execute [4mcommand‐line[24m with [4mpopen[24m(3) and interpolate  its  out‐
                 put.  Unsafe request; disabled by default.
       [1m.ptr      [22mReport  names and positions of all page location traps to the
                 standard error stream.
       [1m.pvs      [22mChange to previous post‐vertical line spacing.
       [1m.pvs [4m[22m±N[24m   Change post‐vertical line spacing according  to  [4m±N[24m  (default
                 scaling unit [1mp[22m).
       [1m.rchar [4m[22mc1[24m [4mc2[24m ...
                 Remove  definition  of each ordinary or special character [4mc1[24m,
                 [4mc2[24m, ... defined by a [1m.char[22m, [1m.fchar[22m, or [1m.schar [22mrequest.
       [1m.rd [4m[22mprompt[0m
                 Read insertion.
       [1m.return   [22mReturn from a macro.
       [1m.return [4m[22manything[0m
                 Return twice, namely from the macro at the current level  and
                 from the macro one level higher.
       [1m.rfschar [4m[22mf[24m [4mc1[24m [4mc2[24m ...
                 Remove  the  font‐specific  definitions of glyphs [4mc1[24m, [4mc2[24m, ...
                 for font [4mf[24m.
       [1m.rj [4m[22mnpl[24m   Break, right‐align the output of the  next  productive  input
                 line without filling, then break again.
       [1m.rj [4m[22mnpl[24m   Break,  right‐align the output of the next [4mnpl[24m productive in‐
                 put lines without filling, then break again.   If  [4mnpl[24m  ≤  0,
                 stop right‐aligning.
       [1m.rm [4m[22mname[24m  Remove request, macro, diversion, or string [4mname[24m.
       [1m.rn [4m[22mold[24m [4mnew[0m
                 Rename request, macro, diversion, or string [4mold[24m to [4mnew[24m.
       [1m.rnn [4m[22mreg1[24m [4mreg2[0m
                 Rename register [4mreg1[24m to [4mreg2[24m.
       [1m.rr [4m[22mident[24m Remove register [4mident[24m.
       [1m.rs       [22mRestore spacing; disable no‐space mode.  See [1m.ns[22m.
       [1m.rt       [22mReturn  [4m(upward[24m  [4monly)[24m  to vertical position marked by [1m.mk [22mon
                 the current page.
       [1m.rt [4m[22mN[24m     Return [4m(upward[24m [4monly)[24m to vertical position [4mN[24m (default  scaling
                 unit [1mv[22m).
       [1m.schar [4m[22mc[24m [4mcontents[0m
                 Define global fallback character (or glyph) [4mc[24m as [4mcontents[24m.
       [1m.shc      [22mReset the soft hyphen character to [1m\[hy][22m.
       [1m.shc [4m[22mc[24m    Set the soft hyphen character to [4mc[24m.
       [1m.shift [4m[22mn[24m  In a macro definition, left‐shift arguments by [4mn[24m positions.
       [1m.sizes [4m[22ms1[24m [4ms2[24m ... [4msn[24m [[1m0[22m]
                 Set  available type sizes similarly to the [1msizes [22mdirective in
                 a [4mDESC[24m file.  Each [4ms[24mi  is  interpreted  in  units  of  scaled
                 points ([1mz[22m).
       [1m.so [4m[22mfile[24m  Replace the request’s control line with the contents of [4mfile[24m,
                 “sourcing” it.
       [1m.soquiet [4m[22mfile[0m
                 As [1m.so[22m, but no warning is emitted if [4mfile[24m does not exist.
       [1m.sp       [22mBreak and move the next text baseline down by one vee, or un‐
                 til springing a page location trap.
       [1m.sp [4m[22mdist[24m  Break  and move the next text baseline down by [4mdist[24m, or until
                 springing a page location trap (default scaling unit  [1mv[22m).   A
                 negative  [4mdist[24m will not reduce the position of the text base‐
                 line below zero.  Prefixing [4mdist[24m with the [1m| [22moperator moves to
                 a position relative to the page top for positive [4mN[24m,  and  the
                 bottom  if [4mN[24m is negative; in all cases, one line height (vee)
                 is added to [4mdist[24m.  [4mdist[24m is ignored inside a diversion.
       [1m.special  [22mReset global list of special fonts to be empty.
       [1m.special [4m[22ms1[24m [4ms2[24m ...
                 Fonts [4ms1[24m, [4ms2[24m, etc. are special and are  searched  for  glyphs
                 not in the current font.
       [1m.spreadwarn[0m
                 Toggle  the  spread  warning on and off (the default) without
                 changing its value.
       [1m.spreadwarn [4m[22mN[0m
                 Emit a [1mbreak [22mwarning if the  additional  space  inserted  for
                 each  space  between  words  in  an  adjusted  output line is
                 greater than or equal to [4mN[24m.  A negative [4mN[24m is  treated  as  0.
                 The  default  scaling  unit is [1mm[22m.  At startup, [1m.spreadwarn [22mis
                 inactive and [4mN[24m is 3 m[1m.[0m
       [1m.ss [4m[22mn[24m     Set minimal inter‐word spacing to [4mn[24m 12ths of  current  font’s
                 space width.
       [1m.ss [4m[22mn[24m [4mm[24m   As  “[1m.ss  [4m[22mn[24m”,  and  set  additional  inter‐sentence  space to
                 [4mm[24m 12ths of current font’s space width.
       [1m.stringdown [4m[22mstringvar[0m
                 Replace each byte in the string named [4mstringvar[24m with its low‐
                 ercase version.
       [1m.stringup [4m[22mstringvar[0m
                 Replace each byte in the string named [4mstringvar[24m with its  up‐
                 percase version.
       [1m.sty [4m[22mn[24m [4mstyle[0m
                 Associate abstract [4mstyle[24m with font position [4mn[24m.
       [1m.substring [4m[22mstr[24m [4mstart[24m [[4mend[24m]
                 Replace  the  string  named [4mstr[24m with its substring bounded by
                 the indices [4mstart[24m and [4mend[24m, inclusive.  Negative indices count
                 backwards from the end of the string.
       [1m.sv       [22mAs [1m.ne[22m, but save 1 v for output with [1m.os [22mrequest.
       [1m.sv [4m[22md[24m     As [1m.ne[22m, but save distance [4md[24m for later output with [1m.os [22mrequest
                 (default scaling unit [1mv[22m).
       [1m.sy [4m[22mcommand‐line[0m
                 Execute [4mcommand‐line[24m with [4msystem[24m(3).   Unsafe  request;  dis‐
                 abled by default.
       [1m.ta [4m[22mn1[24m [4mn2[24m ... [4mn[24mn [1mT [4m[22mr1[24m [4mr2[24m ... [4mr[24mn
                 Set  tabs  at  positions  [4mn1[24m,  [4mn2[24m,  ..., [4mn[24mn, then set tabs at
                 [4mn[24mn+[4mm[24m×[4mr[24mn+[4mr1[24m through [4mn[24mn+[4mm[24m×[4mr[24mn+[4mr[24mn, where [4mm[24m increments from 0,  1,
                 2,  ...  to  the  output line length.  Each [4mn[24m argument can be
                 prefixed with a “[1m+[22m” to place the tab stop [4mni[24m  at  a  distance
                 relative to the previous, [4mn[24m([4mi[24m-1).  Each argument [4mni[24m or [4mri[24m can
                 be suffixed with a letter to align text within the tab column
                 bounded by tab stops [4mi[24m and [4mi[24m+1; “[1mL[22m” for left‐aligned (the de‐
                 fault), “[1mC[22m” for centered, and “[1mR[22m” for right‐aligned.
       [1m.tag[0m
       [1m.taga     [22mReserved for internal use.
       [1m.tc       [22mUnset tab repetition character.
       [1m.tc [4m[22mc[24m     Set tab repetition character to [4mc[24m (default: none).
       [1m.ti [4m[22m±N[24m    Temporarily indent next output line (default scaling unit [1mm[22m).
       [1m.tkf [4m[22mfont[24m [4ms1[24m [4mn1[24m [4ms2[24m [4mn2[0m
                 Enable track kerning for [4mfont[24m.
       [1m.tl '[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'[0m
                 Format three‐part title.
       [1m.tm [4m[22mmessage[0m
                 Write  [4mmessage,[24m  followed by a newline, to the standard error
                 stream.
       [1m.tm1 [4m[22mmessage[0m
                 As [1m.tm[22m, but an initial neutral double quote in [4mmessage[24m is re‐
                 moved, allowing it to contain leading spaces.
       [1m.tmc [4m[22mmessage[0m
                 As [1m.tm1[22m, without emitting a newline.
       [1m.tr [4m[22mabcd[24m...
                 Translate ordinary or special characters [4ma[24m to [4mb[24m, [4mc[24m to [4md[24m,  and
                 so on prior to output.
       [1m.trf [4m[22mfile[24m Transparently  output  the contents of [4mfile.[24m  Unlike [1m.cf[22m, in‐
                 valid input characters in [4mfile[24m are rejected.
       [1m.trin [4m[22mabcd[24m...
                 As [1m.tr[22m, except that [1m.asciify [22mignores the translation  when  a
                 diversion is interpolated.
       [1m.trnt [4m[22mabcd[24m...
                 As  [1m.tr[22m, except that translations are suppressed in the argu‐
                 ment to [1m\![22m.
       [1m.troff    [22mMake the conditional expressions [1mt [22mtrue and [1mn [22mfalse.
       [1m.uf [4m[22mfont[24m  Set underline font used by [1m.ul [22mto [4mfont.[0m
       [1m.ul       [22mUnderline (italicize in [4mtroff[24m mode) the output  of  the  next
                 productive input line.
       [1m.ul [4m[22mnpl[24m   Underline  (italicize  in  [4mtroff[24m mode) the output of the next
                 [4mnpl[24m productive input line.  If [4mnpl[24m=0, stop underlining.
       [1m.unformat [4m[22mdiversion[0m
                 Unformat space characters and tabs in  [4mdiversion[24m,  preserving
                 font information.
       [1m.vpt      [22mEnable vertical position traps.
       [1m.vpt 0    [22mDisable vertical position traps.
       [1m.vs       [22mChange to previous vertical spacing.
       [1m.vs [4m[22m±N[24m    Set vertical spacing to [4m±N[24m (default scaling unit [1mp[22m).
       [1m.warn     [22mEnable all warning categories.
       [1m.warn 0   [22mDisable all warning categories.
       [1m.warn [4m[22mn[24m   Enable  warnings  in  categories  whose  codes  sum to [4mn[24m; see
                 [4mtroff[24m(1).
       [1m.warnscale [4m[22msu[0m
                 Set scaling unit used in certain warnings to [4msu[24m (one of [1mu[22m, [1mi[22m,
                 [1mc[22m, [1mp[22m, or [1mP[22m; default: [1mi[22m).
       [1m.wh [4m[22mvpos[24m  Remove visible page location trap at  [4mvpos[24m  (default  scaling
                 unit [1mv[22m).
       [1m.wh [4m[22mvpos[24m [4mname[0m
                 Plant macro [4mname[24m as page location trap at [4mvpos[24m (default scal‐
                 ing unit [1mv[22m), removing any visible trap already there.
       [1m.while [4m[22mcond‐expr[24m [4manything[0m
                 Repeatedly execute [4manything[24m unless and until [4mcond‐expr[24m evalu‐
                 ates false.
       [1m.write [4m[22mstream[24m [4manything[0m
                 Write [4manything[24m to the stream named [4mstream[24m.
       [1m.writec [4m[22mstream[24m [4manything[0m
                 Similar to [1m.write [22mwithout emitting a final newline.
       [1m.writem [4m[22mstream[24m [4mxx[0m
                 Write  contents  of  macro  or  string [4mxx[24m to the stream named
                 [4mstream[24m.

[1mEscape sequence short reference[0m
       The escape sequences [1m\"[22m, [1m\#[22m, [1m\$[22m, [1m\*[22m, [1m\?[22m, [1m\a[22m, [1m\e[22m, [1m\n[22m, [1m\t[22m,  [1m\g[22m,  [1m\V[22m,  and
       [1m\[4m[22mnewline[24m are interpreted even in copy mode.

       [1m\"     [22mComment.  Everything up to the end of the line is ignored.
       [1m\#     [22mComment.  Everything up to and including the next newline is ig‐
              nored.
       [1m\*[4m[22ms[24m    Interpolate string with one‐character name [4ms[24m.
       [1m\*([4m[22mst[24m  Interpolate string with two‐character name [4mst[24m.
       [1m\*[[4m[22mstring[24m[1m][0m
              Interpolate string with name [4mstring[24m (of arbitrary length).
       [1m\*[[4m[22mstring[24m [4marg[24m ...[1m][0m
              Interpolate  string with name [4mstring[24m (of arbitrary length), tak‐
              ing [4marg[24m ... as arguments.
       [1m\$0    [22mInterpolate name by which currently executing macro was invoked.
       [1m\$[4m[22mn[24m    Interpolate macro or string parameter numbered [4mn[24m (1≤[4mn[24m≤9).
       [1m\$([4m[22mnn[24m  Interpolate macro or string parameter numbered [4mnn[24m (01≤[4mnn[24m≤99).
       [1m\$[[4m[22mnnn[24m[1m][0m
              Interpolate macro or string parameter numbered [4mnnn[24m ([4mnnn[24m≥1).
       [1m\$*    [22mInterpolate concatenation of all  macro  or  string  parameters,
              separated by spaces.
       [1m\$@    [22mInterpolate  concatenation  of  all  macro or string parameters,
              with each surrounded by double quotes and separated by spaces.
       [1m\$^    [22mInterpolate concatenation of all macro or string  parameters  as
              if they were arguments to the [1m.ds [22mrequest.
       [1m\'     [22mis a synonym for [1m\[aa][22m, the acute accent special character.
       [1m\`     [22mis a synonym for [1m\[ga][22m, the grave accent special character.
       [1m\-     [22mis a synonym for [1m\[-][22m, the minus sign special character.
       [1m\_     [22mis a synonym for [1m\[ul][22m, the underrule special character.
       [1m\%     [22mControl hyphenation.
       [1m\!     [22mTransparent  line.   The  remainder  of the input line is inter‐
              preted (1) when the current diversion is read; or (2) if in  the
              top‐level diversion, by the postprocessor (if any).
       [1m\?[4m[22manything[24m[1m\?[0m
              Transparently embed [4manything[24m, read in copy mode, in a diversion,
              or  unformatted  as an output comparand in a conditional expres‐
              sion.
       [1m\[4m[22mspace[24m Move right one word space.
       [1m\~     [22mInsert an unbreakable, adjustable space.
       [1m\0     [22mMove right by the width of a numeral in the current font.
       [1m\|     [22mMove one‐sixth em to the right on typesetters.
       [1m\^     [22mMove one‐twelfth em to the right on typesetters.
       [1m\&     [22mInterpolate a dummy character.
       [1m\)     [22mInterpolate a dummy character that is transparent to end‐of‐sen‐
              tence recognition.
       [1m\/     [22mApply italic correction.  Use between  an  immediately  adjacent
              oblique glyph on the left and an upright glyph on the right.
       [1m\,     [22mApply  left italic correction.  Use between an immediately adja‐
              cent upright glyph on the left  and  an  oblique  glyph  on  the
              right.
       [1m\:     [22mNon‐printing  break  point  (similar to [1m\%[22m, but never produces a
              hyphen glyph).
       [1m\[4m[22mnewline[0m
              Continue current input line on the next.
       [1m\{     [22mBegin conditional input.
       [1m\}     [22mEnd conditional input.
       [1m\([4m[22mgl[24m   Interpolate glyph with two‐character name [4mgl[24m.
       [1m\[[4m[22mglyph[24m[1m][0m
              Interpolate glyph with name [4mglyph[24m (of arbitrary length).
       [1m\[[4m[22mbase‐char[24m [4mcomp[24m ...[1m][0m
              Interpolate composite glyph constructed from [4mbase‐char[24m and  each
              component [4mcomp[24m.
       [1m\[char[4m[22mnnn[24m[1m][0m
              Interpolate  glyph  of  eight‐bit  encoded  character [4mnnn[24m, where
              0≤[4mnnn[24m≤255.
       [1m\[u[4m[22mnnnn[24m[[4mn[24m[[4mn[24m]][1m][0m
              Interpolate  glyph  of  Unicode  character   with   code   point
              [4mnnnn[24m[[4mn[24m[[4mn[24m]] in uppercase hexadecimal.
       [1m\[u[4m[22mbase‐char[24m[[1m_[4m[22mcombining‐component[24m]...[1m][0m
              Interpolate composite glyph from Unicode character [4mbase‐char[24m and
              [4mcombining‐components[24m.
       [1m\a     [22mInterpolate a leader in copy mode.
       [1m\A'[4m[22manything[24m[1m'[0m
              Interpolate  1  if  [4manything[24m is a valid identifier, and 0 other‐
              wise.
       [1m\b'[4m[22mstring[24m[1m'[0m
              Build bracket: pile a sequence of glyphs corresponding  to  each
              character  in [4mstring[24m vertically, and center it vertically on the
              output line.
       [1m\B'[4m[22manything[24m[1m'[0m
              Interpolate 1 if [4manything[24m is a valid numeric expression,  and  0
              otherwise.
       [1m\c     [22mContinue output line at next input line.
       [1m\C'[4m[22mglyph[24m[1m'[0m
              As [1m\[[4m[22mglyph[24m[1m][22m, but compatible with other [4mtroff[24m implementations.
       [1m\d     [22mMove downward ½ em on typesetters.
       [1m\D'[4m[22mdrawing‐command[24m[1m'[0m
              See subsection “Drawing commands” below.
       [1m\e     [22mInterpolate the escape character.
       [1m\E     [22mAs [1m\e[22m, but not interpreted in copy mode.
       [1m\fP    [22mSelect previous font mounting position (abstract style or font);
              same as “[1m.ft[22m” or “[1m.ft P[22m”.
       [1m\f[4m[22mF[24m    Select font mounting position, abstract style, or font with one‐
              character name or one‐digit position [4mF[24m.  [4mF[24m cannot be [1mP[22m.
       [1m\f([4m[22mft[24m  Select font mounting position, abstract style, or font with two‐
              character name or two‐digit position [4mft[24m.
       [1m\f[[4m[22mfont[24m[1m][0m
              Select  font mounting position, abstract style, or font with ar‐
              bitrarily long name or position [4mfont[24m.  [4mfont[24m cannot be [1mP[22m.
       [1m\f[]   [22mSelect previous font mounting position (abstract style or font).
       [1m\F[4m[22mf[24m    Set default font family to that with one‐character name [4mf[24m.
       [1m\F([4m[22mfm[24m  Set default font family to that with two‐character name [4mfm[24m.
       [1m\F[[4m[22mfam[24m[1m][0m
              Set default font family to that with arbitrarily long name [4mfam[24m.
       [1m\F[]   [22mSet default font family to previous value.
       [1m\g[4m[22mr[24m    Interpolate format of register with one‐character name [4mr[24m.
       [1m\g([4m[22mrg[24m  Interpolate format of register with two‐character name [4mrg[24m.
       [1m\g[[4m[22mreg[24m[1m][0m
              Interpolate format of register with arbitrarily long name [4mreg[24m.
       [1m\h'[4m[22mN[24m[1m'  [22mHorizontally move the drawing position by [4mN[24m  ems  (or  specified
              units); [1m| [22mmay be used.  Positive motion is rightward.
       [1m\H'[4m[22mN[24m[1m'  [22mSet  height  of  current  font  to [4mN[24m scaled points (or specified
              units).
       [1m\k[4m[22mr[24m    Mark horizontal position in one‐character register name [4mr[24m.
       [1m\k([4m[22mrg[24m  Mark horizontal position in two‐character register name [4mrg[24m.
       [1m\k[[4m[22mreg[24m[1m][0m
              Mark horizontal  position  in  register  with  arbitrarily  long
              name [4mreg[24m.
       [1m\l'[4m[22mN[24m[[4mc[24m][1m'[0m
              Draw  horizontal  line  of  length  [4mN[24m with character [1mc [22m(default:
              [1m\[ru][22m; default scaling unit [1mm[22m).
       [1m\L'[4m[22mN[24m[[4mc[24m][1m'[0m
              Draw vertical line of length [4mN[24m with character [1mc [22m(default: [1m\[br][22m;
              default scaling unit [1mv[22m).
       [1m\m[4m[22mc[24m    Set stroke color to that with one‐character name [4mc[24m.
       [1m\m([4m[22mcl[24m  Set stroke color to that with two‐character name [4mcl[24m.
       [1m\m[[4m[22mcolor[24m[1m][0m
              Set stroke color to that with arbitrarily long name [4mcolor[24m.
       [1m\m[]   [22mRestore previous stroke color.
       [1m\M[4m[22mc[24m    Set fill color to that with one‐character name [4mc[24m.
       [1m\M([4m[22mcl[24m  Set fill color to that with two‐character name [4mcl[24m.
       [1m\M[[4m[22mcolor[24m[1m][0m
              Set fill color to that with arbitrarily long name [4mcolor[24m.
       [1m\M[]   [22mRestore previous fill color.
       [1m\n[4m[22mr[24m    Interpolate contents of register with one‐character name [4mr[24m.
       [1m\n([4m[22mrg[24m  Interpolate contents of register with two‐character name [4mrg[24m.
       [1m\n[[4m[22mreg[24m[1m][0m
              Interpolate contents of register with arbitrarily long name [4mreg[24m.
       [1m\N'[4m[22mn[24m[1m'  [22mInterpolate glyph with index [4mn[24m in the current font.
       [1m\o'[4m[22mabc[24m...[1m'[0m
              Overstrike centered glyphs of characters [4ma[24m, [4mb[24m, [4mc[24m, and so on.
       [1m\O0    [22mAt the outermost suppression level, disable emission  of  glyphs
              and geometric objects to the output driver.
       [1m\O1    [22mAt  the  outermost  suppression level, enable emission of glyphs
              and geometric objects to the output driver.
       [1m\O2    [22mAt the outermost suppression level, enable glyph  and  geometric
              primitive  emission  to the output driver and write to the stan‐
              dard error stream the page number, four bounding  box  registers
              enclosing  glyphs written since the previous [1m\O [22mescape sequence,
              the page offset, line length, image file name (if any), horizon‐
              tal and vertical device motion quanta, and input file name.
       [1m\O3    [22mBegin a nested suppression level.
       [1m\O4    [22mEnd a nested suppression level.
       [1m\O[5[4m[22mPfile[24m[1m][0m
              At the outermost suppression level, write the name [4mfile[24m  to  the
              standard  error stream at position [4mP[24m, which must be one of [1ml[22m, [1mr[22m,
              [1mc[22m, or [1mi[22m.
       [1m\p     [22mBreak output line at next word boundary; adjust if applicable.
       [1m\r     [22mMove “in reverse” (upward) 1 em.
       [1m\R'[4m[22mname[24m [4m±N[24m[1m'[0m
              Set, increment, or decrement register [4mname[24m by [4mN[24m.
       [1m\s[4m[22m±N[24m   Set/increase/decrease the type size to/by [4mN[24m  scaled  points.   [4mN[0m
              must  be a single digit; 0 restores the previous type size.  (In
              compatibility mode only, a non‐zero  [4mN[24m  must  be  in  the  range
              4–39.)  Otherwise, as [1m.ps [22mrequest.
       [1m\s([4m[22m±N[0m
       [1m\s[4m[22m±[24m[1m([4m[22mN[24m  Set/increase/decrease  the type size to/by [4mN[24m scaled points; [4mN[24m is
              a two‐digit number ≥1.  As [1m.ps [22mrequest.
       [1m\s[[4m[22m±N[24m[1m][0m
       [1m\s[4m[22m±[24m[1m[[4m[22mN[24m[1m][0m
       [1m\s'[4m[22m±N[24m[1m'[0m
       [1m\s[4m[22m±[24m[1m'[4m[22mN[24m[1m' [22mSet/increase/decrease the type size to/by [4mN[24m scaled  points.   As
              [1m.ps [22mrequest.
       [1m\S'[4m[22mN[24m[1m'  [22mSlant  output glyphs by [4mN[24m degrees; the direction of text flow is
              positive.
       [1m\t     [22mInterpolate a tab in copy mode.
       [1m\u     [22mMove upward ½ em on typesetters.
       [1m\v'[4m[22mN[24m[1m'  [22mVertically move the drawing position by  [4mN[24m  vees  (or  specified
              units); [1m| [22mmay be used.  Positive motion is downward.
       [1m\V[4m[22me[24m    Interpolate  contents of environment variable with one‐character
              name [4me[24m.
       [1m\V([4m[22mev[24m  Interpolate contents of environment variable with  two‐character
              name [4mev[24m.
       [1m\V[[4m[22menv[24m[1m][0m
              Interpolate  contents  of  environment variable with arbitrarily
              long name [4menv[24m.
       [1m\w'[4m[22manything[24m[1m'[0m
              Interpolate width of [4manything[24m, formatted in a dummy environment.
       [1m\x'[4m[22mN[24m[1m'  [22mIncrease vertical spacing of pending output line by [4mN[24m  vees  (or
              specified units; negative before, positive after).
       [1m\X'[4m[22manything[24m[1m'[0m
              Write  [4manything[24m  to  [4mtroff[24m  output  as a device control command.
              Within [4manything[24m, the escape sequences [1m\&[22m, [1m\)[22m, [1m\%[22m, and [1m\: [22mare ig‐
              nored; [1m\[4m[22mspace[24m and [1m\~ [22mare converted to single  space  characters;
              and  [1m\\  [22mhas  its  escape character stripped.  So that the basic
              Latin subset of the Unicode character set can  be  reliably  en‐
              coded  in  [4manything,[24m  the special character escape sequences [1m\-[22m,
              [1m\[aq][22m, [1m\[dq][22m, [1m\[ga][22m, [1m\[ha][22m, [1m\[rs][22m, and [1m\[ti] [22mare mapped to basic
              Latin characters; see [4mgroff_char[24m(7).  For  this  transformation,
              character translations and special character definitions are ig‐
              nored.
       [1m\Y[4m[22mn[24m    Write  contents of macro or string [4mn[24m to [4mtroff[24m output as a device
              control command.
       [1m\Y([4m[22mnm[24m  Write contents of macro or string [4mnm[24m to [4mtroff[24m output as a device
              control command.
       [1m\Y[[4m[22mname[24m[1m][0m
              Write contents of macro or string [4mname[24m to [4mtroff[24m output as a  de‐
              vice control command.
       [1m\z[4m[22mc[24m    Format character [4mc[24m with zero width—without advancing the drawing
              position.
       [1m\Z'[4m[22manything[24m[1m'[0m
              Save the drawing position, format [4manything[24m, then restore it.

   [1mDrawing commands[0m
       Drawing commands direct the output device to render geometrical objects
       rather than glyphs.  Specific devices may support only a subset, or may
       feature  additional ones; consult the man page for the output driver in
       use.  Terminal devices in particular implement almost none.

       Rendering starts at the drawing position; when  finished,  the  drawing
       position  is left at the rightmost point of the object, even for closed
       figures, except where noted.  GNU [4mtroff[24m draws  stroked  (outlined)  ob‐
       jects  with  the  stroke  color,  and  shades filled ones with the fill
       color.  See section “Colors” above.  Coordinates [4mh[24m and [4mv[24m are horizontal
       and vertical motions relative to the drawing position or previous point
       in the command.  The default scaling unit for  horizontal  measurements
       (and diameters of circles) is [1mm[22m; for vertical ones, [1mv[22m.

       Circles,  ellipses, and polygons can be drawn stroked or filled.  These
       are independent properties; if you want a filled, stroked  figure,  you
       must  draw  the same figure twice using each drawing command.  A filled
       figure is always smaller than an outlined one  because  the  former  is
       drawn  only within its defined area, whereas strokes have a line thick‐
       ness (set with [1m\D't'[22m).

       [1m\D'~ [4m[22mh1[24m [4mv1[24m ... [4mhn[24m [4mvn[24m[1m'[0m
              Draw B‐spline to each point in sequence, leaving  drawing  posi‐
              tion at ([4mhn[24m, [4mvn[24m).
       [1m\D'a [4m[22mhc[24m [4mvc[24m [4mh[24m [4mv[24m[1m'[0m
              Draw circular arc centered at ([4mhc[24m, [4mvc[24m) counterclockwise from the
              drawing  position  to  a  point  ([4mh[24m,  [4mv[24m) relative to the center.
              ([4mhc[24m, [4mvc[24m) is adjusted to the point nearest the perpendicular  bi‐
              sector of the arc’s chord.
       [1m\D'c [4m[22md[24m[1m'[0m
              Draw circle of diameter [4md[24m with its leftmost point at the drawing
              position.
       [1m\D'C [4m[22md[24m[1m'[0m
              As [1m\D'C'[22m, but the circle is filled.
       [1m\D'e [4m[22mh[24m [4mv[24m[1m'[0m
              Draw  ellipse of width [4mh[24m and height [4mv[24m with its leftmost point at
              the drawing position.
       [1m\D'E [4m[22mh[24m [4mv[24m[1m'[0m
              As [1m\D'e'[22m, but the ellipse is filled.
       [1m\D'l [4m[22mh[24m [4mv[24m[1m'[0m
              Draw line from the drawing position to ([4mh[24m, [4mv[24m).
       [1m\D'p [4m[22mh1[24m [4mv1[24m ... [4mhn[24m [4mvn[24m[1m'[0m
              Draw polygon with vertices at drawing position and each point in
              sequence.  GNU [4mtroff[24m closes the polygon by drawing a  line  from
              ([4mhn[24m,  [4mvn[24m)  back to the initial drawing position.  Afterward, the
              drawing position is left at ([4mhn[24m, [4mvn[24m).
       [1m\D'P [4m[22mh1[24m [4mv1[24m ... [4mhn[24m [4mvn[24m[1m'[0m
              As [1m\D'p'[22m, but the polygon is filled.
       [1m\D't [4m[22mn[24m[1m'[0m
              Set stroke thickness of geometric objects to to [4mn[24m  basic  units.
              A  zero [4mn[24m selects the minimal supported thickness.  A negative [4mn[0m
              selects a thickness proportional to the type size; this  is  the
              default.

   [1mDevice control commands[0m
       The  [1m.device [22mand [1m.devicem [22mrequests, and [1m\X [22mand [1m\Y [22mescape sequences, en‐
       able documents to pass information directly to a postprocessor.   These
       are  useful  for exercising device‐specific capabilities that the [4mgroff[0m
       language does not abstract or generalize; such  functions  include  the
       embedding of hyperlinks and image files.  Device‐specific functions are
       documented in each output driver’s man page.

[1mStrings[0m
       [4mgroff[24m supports strings primarily for user convenience.  Conventionally,
       if one would define a macro only to interpolate a small amount of text,
       without  invoking  requests  or calling any other macros, one defines a
       string instead.  Only one string is predefined by the language.

       \*[[1m.T[22m]    Contains the name of the output device (for  example,  “[1mutf8[22m”
                 or “[1mpdf[22m”[1m).[0m

       The  [1m.ds  [22mrequest  creates a string with a specified name and contents.
       If the identifier named by [1m.ds [22malready exists as an alias,  the  target
       of  the  alias  is redefined.  If [1m.ds [22mis called with only one argument,
       the named string becomes empty.  Otherwise, [4mtroff[24m stores the  remainder
       of the control line in copy mode; see subsection “Copy mode” below.

       The  [1m\* [22mescape sequence dereferences a string’s name, interpolating its
       contents.  If the name does not exist, it is defined as empty,  nothing
       is  interpolated, and a warning in category “[1mmac[22m” is emitted.  See sec‐
       tion “Warnings” in [4mtroff[24m(1).  The bracketed interpolation form  accepts
       arguments that are handled as macro arguments are; see section “Calling
       macros”  above.   In  contrast  to  macro  calls, however, if a closing
       bracket [1m] [22moccurs in a string argument, that argument must  be  enclosed
       in  double quotes.  [1m\* [22mis interpreted even in copy mode.  When defining
       strings, argument interpolations must be escaped if they are to  refer‐
       ence  parameters from the calling context; see section “Parameters” be‐
       low.

       An initial neutral double quote [1m" [22min the string contents is stripped to
       allow embedding of leading spaces.  Any other [1m" [22mis  interpreted  liter‐
       ally, but it is wise to use the special character escape sequence [1m\[dq][0m
       instead  if  the  string might be interpolated as part of a macro argu‐
       ment; see section “Calling macros” above.  Strings are not limited to a
       single input line of text.  [1m\[4m[22mnewline[24m works just as it  does  elsewhere.
       The resulting string is stored [4mwithout[24m the newlines.  Care is therefore
       required  when  interpolating strings while filling is disabled.  It is
       not possible to embed a newline in a string that will be interpreted as
       such when the string is interpolated.  To achieve that effect,  use  [1m\*[0m
       to interpolate a macro instead.

       The  [1m.as  [22mrequest  is similar to [1m.ds [22mbut appends to a string instead of
       redefining it.  If [1m.as [22mis called with only one argument,  no  operation
       is performed (beyond dereferencing the string).

       Because  strings are similar to macros, they too can be defined to sup‐
       press AT&T [4mtroff[24m compatibility mode enablement when  interpolated;  see
       section  “Compatibility mode” below.  The [1m.ds1 [22mrequest defines a string
       that suspends compatibility mode when the string is later interpolated.
       [1m.as1 [22mis likewise similar to [1m.as[22m, with compatibility mode suspended when
       the appended portion of the string is later interpolated.

       [1mCaution: [22mUnlike other requests, the second argument to  these  requests
       consumes  the  remainder  of the input line, including trailing spaces.
       Ending string definitions (and appendments) with  a  comment,  even  an
       empty  one,  prevents  unwanted  space  from  creeping into them during
       source document maintenance.

       Several  requests  exist  to  perform  rudimentary  string  operations.
       Strings  can  be  queried  ([1m.length[22m)  and  modified ([1m.chop[22m, [1m.substring[22m,
       [1m.stringup[22m, [1m.stringdown[22m), and their names can be manipulated through re‐
       naming, removal, and aliasing ([1m.rn[22m, [1m.rm[22m, [1m.als).[0m

       When a request, macro, string, or diversion is  aliased,  redefinitions
       and  appendments “write through” alias names.  To replace an alias with
       a separately defined object, you must use the [1mrm [22mrequest  on  its  name
       first.

[1mRegisters[0m
       In  the [4mroff[24m language, numbers can be stored in [4mregisters.[24m  Many built‐
       in registers exist, supplying anything from the date to details of for‐
       matting parameters.  You can also define your own.  See section  “Iden‐
       tifiers”  above for information on constructing a valid name for a reg‐
       ister.

       Define registers and update their values with the [1mnr [22mrequest or the  [1m\R[0m
       escape sequence.

       Registers can also be incremented or decremented by a configured amount
       at the time they are interpolated.  The value of the increment is spec‐
       ified  with a third argument to the [1m.nr [22mrequest, and a special interpo‐
       lation syntax, [1m\n[4m[22m±[24m is used to alter and then  retrieve  the  register’s
       value.   Together,  these features are called [4mauto‐increment[24m.  (A nega‐
       tive auto‐increment can be considered an “auto‐decrement”.)

       Many predefined registers are available.  In  the  following  presenta‐
       tion,  the register interpolation syntax [1m\n[[4m[22mname[24m[1m] [22mis used to refer to a
       register [4mname[24m to clearly distinguish it from a string or request  [4mname[24m.
       The  register  name  space  is  separate  from  that used for requests,
       macros, strings, and diversions.  Bear in mind that  the  symbols  [1m\n[][0m
       are [4mnot[24m part of the register name.

   [1mRead‐only registers[0m
       Predefined  registers whose identifiers start with a dot are read‐only.
       Many are Boolean‐valued.  Some are string‐valued, meaning that they in‐
       terpolate text.  A register name (without the dot) is often  associated
       with a request of the same name; exceptions are noted.

       \n[[1m.$[22m]         Count  of  arguments  passed  to  currently interpolated
                      macro or string.
       \n[[1m.a[22m]         Amount of extra post‐vertical line space; see [1m\x[22m.
       \n[[1m.A[22m]         Approximate output is being formatted  (Boolean‐valued);
                      see [4mtroff[24m [1m-a [22moption.
       \n[[1m.b[22m]         Font emboldening offset; see [1m.bd[22m.
       \n[[1m.br[22m]        The  normal  control character was used to call the cur‐
                      rently interpolated macro (Boolean‐valued).
       \n[[1m.c[22m]         Input line number; see [1m.lf [22mand register “[1mc.[22m”.
       \n[[1m.C[22m]         Compatibility mode is enabled (Boolean‐valued); see [1m.cp[22m.
                      Always false when processing [1m.do[22m; see register [1m.cp[22m.
       \n[[1m.cdp[22m]       Depth of last glyph formatted in the environment;  posi‐
                      tive if glyph extends below the baseline.
       \n[[1m.ce[22m]        Count of output lines remaining to be centered.
       \n[[1m.cht[22m]       Height of last glyph formatted in the environment; posi‐
                      tive if glyph extends above the baseline.
       \n[[1m.color[22m]     Color output is enabled (Boolean‐valued).
       \n[[1m.cp[22m]        Within  [1m.do[22m,  the saved value of compatibility mode; see
                      register [1m.C[22m.
       \n[[1m.csk[22m]       Skew of the last glyph  formatted  in  the  environment;
                      skew  is  how  far to the right of the center of a glyph
                      the center of  an  accent  over  that  glyph  should  be
                      placed.
       \n[[1m.d[22m]         Vertical drawing position in diversion.
       \n[[1m.ev[22m]        Name of environment (string‐valued).
       \n[[1m.f[22m]         Mounting position of selected font; see [1m.ft [22mand [1m\f[22m.
       \n[[1m.F[22m]         Name of input file (string‐valued); see [1m.lf[22m.
       \n[[1m.fam[22m]       Name of default font family (string‐valued).
       \n[[1m.fn[22m]        Resolved  name of selected font (string‐valued); see [1m.ft[0m
                      and [1m\f[22m.
       \n[[1m.fp[22m]        Next non‐zero free font mounting position index.
       \n[[1m.g[22m]         Always true in GNU [4mtroff[24m (Boolean‐valued).
       \n[[1m.h[22m]         Text baseline high‐water mark on page or in diversion.
       \n[[1m.H[22m]         Horizontal motion quantum  of  output  device  in  basic
                      units.
       \n[[1m.height[22m]    Font height; see [1m\H[22m.
       \n[[1m.hla[22m]       Hyphenation language in environment (string‐valued).
       \n[[1m.hlc[22m]       Count  of  immediately  preceding consecutive hyphenated
                      lines in environment.
       \n[[1m.hlm[22m]       Maximum quantity of consecutive hyphenated lines allowed
                      in environment.
       \n[[1m.hy[22m]        Automatic hyphenation mode in environment.
       \n[[1m.hym[22m]       Hyphenation margin in environment.
       \n[[1m.hys[22m]       Hyphenation space adjustment threshold in environment.
       \n[[1m.i[22m]         Indentation amount; see [1m.in[22m.
       \n[[1m.in[22m]        Indentation amount  applicable  to  the  pending  output
                      line; see [1m.ti[22m.
       \n[[1m.int[22m]       Previous output line was “interrupted” or continued with
                      [1m\c [22m(Boolean‐valued).
       \n[[1m.j[22m]         Adjustment  mode encoded as an integer; see [1m.ad [22mand [1m.na[22m.
                      Do not interpret or perform arithmetic on its value.
       \n[[1m.k[22m]         Horizontal drawing position relative to indentation.
       \n[[1m.kern[22m]      Pairwise kerning is enabled (Boolean‐valued).
       \n[[1m.l[22m]         Line length; see [1m.ll[22m.
       \n[[1m.L[22m]         Line spacing; see [1m.ls[22m.
       \n[[1m.lg[22m]        Ligature mode.
       \n[[1m.linetabs[22m]  Line‐tabs mode is enabled (Boolean‐valued).
       \n[[1m.ll[22m]        Line length applicable to the pending output line.
       \n[[1m.lt[22m]        Title length.
       \n[[1m.m[22m]         Stroke color (string‐valued); see [1m.gcolor [22mand [1m\m[22m.  Empty
                      if the stroke color is the default.
       \n[[1m.M[22m]         Fill color (string‐valued); see [1m.fcolor [22mand  [1m\M[22m.   Empty
                      if the fill color is the default.
       \n[[1m.n[22m]         Length of formatted output on previous output line.
       \n[[1m.ne[22m]        Amount  of  vertical  space  required  by  last [1m.ne [22mthat
                      caused a trap to be sprung; also see register [1m.trunc[22m.
       \n[[1m.nm[22m]        Output line numbering is enabled (Boolean‐valued).
       \n[[1m.nn[22m]        Count of output lines remaining to have  numbering  sup‐
                      pressed.
       \n[[1m.ns[22m]        No‐space mode is enabled (Boolean‐valued).
       \n[[1m.o[22m]         Page offset; see [1m.po[22m.
       \n[[1m.O[22m]         Output suppression nesting level; see [1m\O[22m.
       \n[[1m.p[22m]         Page length; see [1m.pl[22m.
       \n[[1m.P[22m]         The  page  is  selected for output (Boolean‐valued); see
                      [4mtroff[24m [1m-o [22moption.
       \n[[1m.pe[22m]        Page ejection is in progress (Boolean‐valued).
       \n[[1m.pn[22m]        Number of the next page.
       \n[[1m.ps[22m]        Type size in scaled points.
       \n[[1m.psr[22m]       Most recently requested type size in scaled points;  see
                      [1m.ps [22mand [1m\s[22m.
       \n[[1m.pvs[22m]       Post‐vertical line spacing.
       \n[[1m.R[22m]         Count  of  available  unused registers; always 10,000 in
                      GNU [4mtroff[24m.
       \n[[1m.rj[22m]        Count of lines remaining to be right‐aligned.
       \n[[1m.s[22m]         Type size in points as a decimal  fraction  (string‐val‐
                      ued); see [1m.ps [22mand [1m\s[22m.
       \n[[1m.slant[22m]     Slant of font in degrees; see [1m\S[22m.
       \n[[1m.sr[22m]        Most recently requested type size in points as a decimal
                      fraction (string‐valued); see [1m.ps [22mand [1m\s[22m.
       \n[[1m.ss[22m]        Size  of  minimal  inter‐word  space  in twelfths of the
                      space width of the selected font.
       \n[[1m.sss[22m]       Size of additional inter‐sentence space in  twelfths  of
                      the space width of the selected font.
       \n[[1m.sty[22m]       Selected abstract style (string‐valued); see [1m.ft [22mand [1m\f[22m.
       \n[[1m.t[22m]         Distance  to  next  vertical  position trap; see [1m.wh [22mand
                      [1m.ch[22m.
       \n[[1m.T[22m]         An output device was explicitly  selected  (Boolean‐val‐
                      ued); see [4mtroff[24m [1m-T [22moption.
       \n[[1m.tabs[22m]      Representation of tab settings suitable for use as argu‐
                      ment to [1m.ta [22m(string‐valued).
       \n[[1m.trunc[22m]     Amount  of vertical space truncated by the most recently
                      sprung vertical position  trap,  or,  if  the  trap  was
                      sprung  by  an  [1m.ne[22m, minus the amount of vertical motion
                      produced by [1m.ne[22m; also see register [1m.ne[22m.
       \n[[1m.u[22m]         Filling is enabled (Boolean‐valued); see [1m.fi [22mand [1m.nf[22m.
       \n[[1m.U[22m]         Unsafe mode is enabled (Boolean‐valued);  see  [4mtroff[24m  [1m-U[0m
                      option.
       \n[[1m.v[22m]         Vertical line spacing; see [1m.vs[22m.
       \n[[1m.V[22m]         Vertical  motion  quantum  of the output device in basic
                      units.
       \n[[1m.vpt[22m]       Vertical position traps are enabled (Boolean‐valued).
       \n[[1m.w[22m]         Width of previous glyph formatted in the environment.
       \n[[1m.warn[22m]      Sum of the numeric codes of enabled warning categories.
       \n[[1m.x[22m]         Major version number of the running [4mtroff[24m formatter.
       \n[[1m.y[22m]         Minor version number of the running [4mtroff[24m formatter.
       \n[[1m.Y[22m]         Revision number of the running [4mtroff[24m formatter.
       \n[[1m.z[22m]         Name of diversion (string‐valued).  Empty if  output  is
                      directed to the top‐level diversion.
       \n[[1m.zoom[22m]      Zoom multiplier of current font (in thousandths; zero if
                      no magnification); see [1m.fzoom[22m.

   [1mWritable predefined registers[0m
       Several  registers are predefined but also modifiable; some are updated
       upon interpretation of certain requests or escape sequences.  Date‐ and
       time‐related registers are set to  the  local  time  as  determined  by
       [4mlocaltime[24m(3)  when  the formatter launches.  This initialization can be
       overridden by [4mSOURCE_DATE_EPOCH[24m and [4mTZ[24m; see  section  “Environment”  of
       [4mgroff[24m(1).

       \n[[1m$$[22m]         Process ID of [4mtroff[24m.
       \n[[1m%[22m]          Page number.
       \n[[1mc.[22m]         Input line number.
       \n[[1mct[22m]         Union  of  character  types  of each glyph rendered into
                      dummy environment by [1m\w[22m.
       \n[[1mdl[22m]         Width of last closed diversion.
       \n[[1mdn[22m]         Height of last closed diversion.
       \n[[1mdw[22m]         Day of the week (1–7; 1 is Sunday).
       \n[[1mdy[22m]         Day of the month (1–31).
       \n[[1mhours[22m]      Count of hours elapsed since midnight (0–23).
       \n[[1mhp[22m]         Horizontal drawing position relative to start  of  input
                      line.
       \n[[1mllx[22m]        Lower‐left  [4mx[24m  coordinate (in PostScript units) of Post‐
                      Script image; see [1m.psbb[22m.
       \n[[1mlly[22m]        Lower‐left [4my[24m coordinate (in PostScript units)  of  Post‐
                      Script image; see [1m.psbb[22m.
       \n[[1mln[22m]         Output line number; see [1m.nm[22m.
       \n[[1mlsn[22m]        Count of leading spaces on input line.
       \n[[1mlss[22m]        Amount  of  horizontal  space  corresponding  to leading
                      spaces on input line.
       \n[[1mminutes[22m]    Count of minutes elapsed in the hour (0–59).
       \n[[1mmo[22m]         Month of the year (1–12).
       \n[[1mnl[22m]         Vertical drawing position.
       \n[[1mopmaxx[22m]
       \n[[1mopmaxy[22m]
       \n[[1mopminx[22m]
       \n[[1mopminy[22m]     These four registers  mark  the  top  left‐  and  bottom
                      right‐hand  corners of a rectangle encompassing all for‐
                      matted output on the page.  They are reset to -1 by  [1m\O0[0m
                      or [1m\O1[22m.
       \n[[1mrsb[22m]        As  register [1msb[22m, adding maximum glyph height to measure‐
                      ment.
       \n[[1mrst[22m]        As register [1mst[22m, adding maximum glyph depth  to  measure‐
                      ment.
       \n[[1msb[22m]         Maximum displacement of text baseline below its original
                      position after rendering into dummy environment by [1m\w[22m.
       \n[[1mseconds[22m]    Count of seconds elapsed in the minute (0–60).
       \n[[1mskw[22m]        Skew  of  last  glyph rendered into dummy environment by
                      [1m\w[22m.
       \n[[1mslimit[22m]     The maximum depth of [4mtroff[24m’s internal input  stack.   If
                      ≤0,  there  is  no  limit:  recursion can continue until
                      available memory is exhausted.  The default is 1,000.
       \n[[1mssc[22m]        Subscript correction of last glyph rendered  into  dummy
                      environment by [1m\w[22m.
       \n[[1mst[22m]         Maximum displacement of text baseline above its original
                      position after rendering into dummy environment by [1m\w[22m.
       \n[[1msystat[22m]     Return value of [4msystem()[24m function; see [1m.sy[22m.
       \n[[1murx[22m]        Upper‐right  [4mx[24m coordinate (in PostScript units) of Post‐
                      Script image; see [1m.psbb[22m.
       \n[[1mury[22m]        Upper‐right [4my[24m coordinate (in PostScript units) of  Post‐
                      Script image; see [1m.psbb[22m.
       \n[[1myear[22m]       Gregorian year.
       \n[[1myr[22m]         Gregorian year minus 1900.

[1mUsing fonts[0m
       In  digital  typography, a [4mfont[24m is a collection of characters in a spe‐
       cific typeface that a device can render as glyphs at  a  desired  size.
       (Terminals  and  some output devices have fonts that render at only one
       or two sizes.  As examples of the latter, take the [4mgroff[24m  [1mlj4  [22mdevice’s
       Lineprinter,  and [1mlbp[22m’s Courier and Elite faces.)  A [4mroff[24m formatter can
       change typefaces at any point in the text.  The basic faces are  a  set
       of  [4mstyles[24m  combining  upright and slanted shapes with normal and heavy
       stroke weights: “[1mR[22m”, “[1mI[22m”, “[1mB[22m”, and “[1mBI[22m”—these stand  for  [4mroman,[24m  [4mbold,[0m
       [4mitalic,[24m  and  [4mbold‐italic.[24m  For linguistic text, GNU [4mtroff[24m groups type‐
       faces into [4mfamilies[24m containing each of these styles.   (Font  designers
       prepare  families  such  that the styles share esthetic properties.)  A
       [4mtext[24m [4mfont[24m is thus often a family combined with a style, but it need not
       be: consider the  [1mps  [22mand  [1mpdf  [22mdevices’  [1mZCMI  [22m(Zapf  Chancery  Medium
       italic)—often,  no other style of Zapf Chancery Medium is provided.  On
       typesetting devices, at least one [4mspecial[24m [4mfont[24m is available, comprising
       [4munstyled[24m glyphs for mathematical operators and other purposes.

       Like AT&T [4mtroff,[24m GNU [4mtroff[24m does not itself load or manipulate a digital
       font file; instead it works with a [4mfont[24m [4mdescription[24m [4mfile[24m  that  charac‐
       terizes it, including its glyph repertoire and the [4mmetrics[24m (dimensions)
       of  each  glyph.   This information permits the formatter to accurately
       place glyphs with respect to each other.  Before using a font  descrip‐
       tion,  the formatter associates it with a [4mmounting[24m [4mposition,[24m a place in
       an ordered list of available typefaces.  So that a document need not be
       strongly coupled to a specific font family, in GNU [4mtroff[24m an output  de‐
       vice  can associate a style in the abstract sense with a mounting posi‐
       tion.  Thus the default family can be combined  with  a  style  dynami‐
       cally, producing a [4mresolved[24m [4mfont[24m [4mname.[0m

       Fonts  often  have  trademarked names, and even Free Software fonts can
       require renaming upon modification.  [4mgroff[24m maintains a convention  that
       a  device’s  serif font family is given the name [1mT [22m(“Times”), its sans‐
       serif family [1mH [22m(“Helvetica”), and its monospaced family [1mC  [22m(“Courier”).
       Historical  inertia has driven [4mgroff[24m’s font identifiers to short upper‐
       case abbreviations of font names, as with [1mTR[22m, [1mTB[22m, [1mTI[22m, [1mTBI[22m, and  a  spe‐
       cial font [1mS[22m.

       The  default  family  used  with  abstract styles can be changed at any
       time; initially, it is [1mT[22m.  Typically, abstract styles are  arranged  in
       the  first  four  mounting positions in the order shown above.  The de‐
       fault mounting position, and therefore style, is always [1m1 [22m([1mR[22m).  By  is‐
       suing  appropriate  formatter  instructions, you can override these de‐
       faults before your document writes its first glyph.

       Terminal output devices cannot change font families  and  lack  special
       fonts.   They  support  style  changes  by overstriking, or by altering
       ISO 6429/ECMA‐48 [4mgraphic[24m [4mrenditions[24m (character cell attributes).

[1mHyphenation[0m
       When filling, [4mgroff[24m hyphenates words as needed  at  user‐specified  and
       automatically  determined  hyphenation  points.   Explicitly hyphenated
       words such as “mother‐in‐law” are always eligible  for  breaking  after
       each  of  their hyphens.  The hyphenation character [1m\% [22mand non‐printing
       break point [1m\: [22mescape sequences may be used to control the  hyphenation
       and  breaking  of  individual words.  The [1m.hw [22mrequest sets user‐defined
       hyphenation points for specified words at  any  subsequent  occurrence.
       Otherwise,  [4mgroff[24m  determines  hyphenation  points automatically by de‐
       fault.

       Several requests influence automatic hyphenation.  Because  conventions
       vary,  a  variety of hyphenation modes is available to the [1m.hy [22mrequest;
       these determine whether hyphenation will  apply  to  a  word  prior  to
       breaking  a  line at the end of a page (more or less; see below for de‐
       tails), and at which positions within that  word  automatically  deter‐
       mined  hyphenation points are permissible.  The default is “[1m1[22m” for his‐
       torical reasons, but this is not an appropriate value for  the  English
       hyphenation  patterns used by [4mgroff[24m; localization macro files loaded by
       [4mtroffrc[24m and macro packages often override it.

       [1m0      [22mdisables hyphenation.

       [1m1      [22menables hyphenation except after the first and before  the  last
              character of a word.

       The  remaining values “imply” [1m1[22m; that is, they enable hyphenation under
       the same conditions as “[1m.hy 1[22m”, and then  apply  or  lift  restrictions
       relative to that basis.

       [1m2      [22mdisables  hyphenation  of the last word on a page.  (Hyphenation
              is prevented if the next page location trap  is  closer  to  the
              vertical  drawing position than the next text baseline would be.
              See section “Traps” below.)

       [1m4      [22mdisables hyphenation before the last two characters of a word.

       [1m8      [22mdisables hyphenation after the first two characters of a word.

       [1m16     [22menables hyphenation before the last character of a word.

       [1m32     [22menables hyphenation after the first character of a word.

       Apart from value 2, restrictions imposed by the  hyphenation  mode  are
       [4mnot[24m respected for words whose hyphenations have been specified with the
       hyphenation character (“[1m\%[22m” by default) or the [1m.hw [22mrequest.

       Nonzero  values are additive.  For example, mode 12 causes [4mgroff[24m to hy‐
       phenate neither the last two nor the first two characters  of  a  word.
       Some  values  cannot  be used together because they contradict; for in‐
       stance, values 4 and 16, and values 8 and 32.  As noted, it  is  super‐
       fluous to add 1 to any non‐zero even mode.

       The  places  within a word that are eligible for hyphenation are deter‐
       mined by language‐specific data ([1m.hla[22m, [1m.hpf[22m, and [1m.hpfa[22m) and  lettercase
       relationships  ([1m.hcode  [22mand  [1m.hpfcode[22m).   Furthermore, hyphenation of a
       word might be suppressed due to a limit on consecutive hyphenated lines
       ([1m.hlm[22m), a minimum line length threshold ([1m.hym[22m), or because the line can
       instead be adjusted with additional inter‐word space ([1m.hys[22m).

[1mLocalization[0m
       The set of hyphenation patterns is associated with the hyphenation lan‐
       guage set by the [1m.hla [22mrequest.  The [1m.hpf [22mrequest is usually invoked  by
       a  localization file loaded by the [4mtroffrc[24m file.  [4mgroff[24m provides local‐
       ization files for several languages; see [4mgroff_tmac[24m(5).

[1mWriting macros[0m
       The [1m.de [22mrequest defines a macro named for its argument.  If  that  name
       already  exists  as an alias, the target of the alias is redefined; see
       section “Strings” above.  [4mtroff[24m enters “copy mode” (see below), storing
       subsequent input lines as the definition.  If the optional second argu‐
       ment is not specified, the definition ends with the control  line  “[1m..[22m”
       (two  dots).  Alternatively, a second argument names a macro whose call
       syntax ends the definition; this “end macro” is then  called  normally.
       Spaces  or  tabs are permitted after the first control character in the
       line containing this ending token, but a tab immediately after the  to‐
       ken  prevents  its recognition as the end of a macro definition.  Macro
       definitions can be nested if they use distinct end macros or  if  their
       ending  tokens  are sufficiently escaped.  An end macro need not be de‐
       fined until it is called.  This fact enables a nested macro  definition
       to begin inside one macro and end inside another.

       Variants of [1m.de [22mdisable compatibility mode and/or indirect the names of
       the  macros  specified  for  definition or termination: these are [1m.de1[22m,
       [1m.dei[22m, and [1m.dei1[22m.  Append to macro definitions with [1m.am[22m, [1m.am1[22m, [1m.ami[22m, and
       [1m.ami1[22m.  The [1m.als[22m, [1m.rm[22m, and [1m.rn [22mrequests create an alias of, remove, and
       rename a macro, respectively.  [1m.return [22mstops the execution of  a  macro
       immediately, returning to the enclosing context.

   [1mParameters[0m
       Macro  call  and  string interpolation parameters can be accessed using
       escape sequences starting with “[1m\$[22m”.   The  [1m\n[.$]  [22mread‐only  register
       stores  the  count  of  parameters  available to a macro or string; its
       value can be changed by the [1m.shift [22mrequest, which  dequeues  parameters
       from  the  current list.  The [1m\$0 [22mescape sequence interpolates the name
       by which a macro was called.  Applying string interpolation to a  macro
       does not change this name.

   [1mCopy mode[0m
       When [4mtroff[24m processes certain requests, most importantly those which de‐
       fine or append to a macro or string, it does so in [4mcopy[24m [4mmode[24m: it copies
       the  characters  of the definition into a dedicated storage region, in‐
       terpolating the escape sequences [1m\n[22m, [1m\g[22m, [1m\$[22m, [1m\*[22m, [1m\V[22m, and  [1m\?  [22mnormally;
       interpreting  [1m\[4m[22mnewline[24m  immediately; discarding comments [1m\" [22mand [1m\#[22m; in‐
       terpolating the current leader, escape, or tab character with  [1m\a[22m,  [1m\e[22m,
       and  [1m\t[22m, respectively; and storing all other escape sequences in an en‐
       coded form.  The complement of copy mode—a  [4mroff[24m  formatter’s  behavior
       when  not  defining or appending to a macro, string, or diversion—where
       all macros are interpolated, requests invoked,  and  valid  escape  se‐
       quences processed immediately upon recognition, can be termed [4minterpre‐[0m
       [4mtation[24m [4mmode[24m.

       The  escape  character,  [1m\ [22mby default, can escape itself.  This enables
       you to control whether a given [1m\n[22m, [1m\g[22m, [1m\$[22m, [1m\*[22m, [1m\V[22m,  or  [1m\?  [22mescape  se‐
       quence  is  interpreted at the time the macro containing it is defined,
       or later when the macro is called.

       You can think of [1m\\ [22mas a “delayed” backslash; it is the escape  charac‐
       ter followed by a backslash from which the escape character has removed
       its special meaning.  Consequently, [1m\\ [22mis not an escape sequence in the
       usual  sense.  In any escape sequence [1m\[4m[22mX[24m that [4mtroff[24m does not recognize,
       the escape character is ignored and [4mX[24m is output.  An  unrecognized  es‐
       cape  sequence  causes  a warning in category “[1mescape[22m”, with two excep‐
       tions, [1m\\ [22mbeing one.  The other is [1m\.[22m, which escapes the control  char‐
       acter.   It is used to permit nested macro definitions to end without a
       named macro call to conclude them.  Without a syntax for  escaping  the
       control  character,  this would not be possible.  [4mroff[24m documents should
       not use the [1m\\ [22mor [1m\. [22mcharacter sequences outside  of  copy  mode;  they
       serve  only  to  obfuscate  the  input.  Use [1m\e [22mto represent the escape
       character, [1m\[rs] [22mto obtain a backslash glyph, and [1m\&  [22mbefore  [1m.  [22mand  [1m'[0m
       where  [4mtroff[24m expects them as control characters if you mean to use them
       literally.

       Macro definitions can be nested to arbitrary depth.  In “[1m\\[22m”, each  es‐
       cape  character  is interpreted twice—once in copy mode, when the macro
       is defined, and once in interpretation mode, when the macro is  called.
       This fact leads to exponential growth in the quantity of escape charac‐
       ters  required  to delay interpolation of [1m\n[22m, [1m\g[22m, [1m\$[22m, [1m\*[22m, [1m\V[22m, and [1m\? [22mat
       each nesting level.  An alternative is to use [1m\E[22m, which  represents  an
       escape  character  that is not interpreted in copy mode.  Because [1m\. [22mis
       not a true escape sequence, we can’t use [1m\E [22mto keep “[1m..[22m” from ending  a
       macro  definition prematurely.  If the multiplicity of backslashes com‐
       plicates maintenance, use end macros.

[1mTraps[0m
       [4mTraps[24m are locations in the output, or conditions  on  the  input  that,
       when reached or fulfilled, call a specified macro.  A [4mvertical[24m [4mposition[0m
       [4mtrap[24m  calls  a  macro  when  the  formatter’s vertical drawing position
       reaches or passes, in the downward direction, a certain location on the
       output page or in a diversion.  Its applications include  setting  page
       headers  and  footers,  body  text  in multiple columns, and footnotes.
       These traps can occur at a given location on the page ([1m.wh[22m, [1m.ch[22m); at  a
       given location in the current diversion ([1m.dt[22m)—together, these are known
       as  vertical  position  traps,  which  can  be  disabled and re‐enabled
       ([1m.vpt[22m).

       A diversion is not formatted in the context of a page, so it lacks page
       location traps; instead it can have a [4mdiversion[24m [4mtrap.[24m  There can  exist
       at most one such vertical position trap per diversion.

       Other  kinds  of  trap can be planted at a blank line ([1m.blm[22m); at a line
       with leading space characters ([1m.lsm[22m); after a certain number of produc‐
       tive input lines ([1m.it[22m, [1m.itc[22m); or at the end  of  input  ([1m.em[22m).   Macros
       called by traps are passed no arguments.  Setting a trap is also called
       [4mplanting[24m  one.   It  is  said that a trap is [4msprung[24m if its condition is
       fulfilled.

       Registers associated with trap  management  include  vertical  position
       trap  enablement status ([1m\n[.vpt][22m), distance to the next trap ([1m\n[.t][22m),
       amount of needed ([1m.ne[22m‐requested) space that caused the most recent ver‐
       tical position trap to be sprung  ([1m\n[.ne][22m),  amount  of  needed  space
       truncated  from the amount requested ([1m\n[.trunc][22m), page ejection status
       ([1m\n[.pe][22m), and leading space count ([1m\n[.lsn][22m)  with  its  corresponding
       amount of motion ([1m\n[.lss][22m).

   [1mPage location traps[0m
       A  [4mpage[24m  [4mlocation[24m  [4mtrap[24m is a vertical position trap that applies to the
       page; that is, to undiverted output.  Many can be present; manage  them
       with  the  [1mwh  [22mand  [1mch  [22mrequests.  Non‐negative page locations given to
       these requests set the trap relative to the top of the  page;  negative
       values set the trap relative to the bottom of the page.  It is not pos‐
       sible  to plant a trap less than one basic unit from the page bottom: a
       location of “-0” is interpreted as “0”, the top of the page.  An exist‐
       ing [4mvisible[24m trap (see below) at the same location is removed;  this  is
       [1m.wh[22m’s sole function if its second argument is missing.

       A  trap  is  sprung only if it is [4mvisible,[24m meaning that its location is
       reachable on the page and it is not hidden by another trap at the  same
       location  already  planted  there.   (A trap planted at “20i” or “-30i”
       will not be sprung on a page of length “11i”.)

       A trap above the top or at or below the bottom of the page can be  made
       visible  by  either moving it into the page area or increasing the page
       length so that the trap is on the page.  Negative  trap  values  always
       use the [4mcurrent[24m page length; they are not converted to an absolute ver‐
       tical  position.   Use [1m.ptr [22mto dump page location traps to the standard
       error stream; their positions are reported in basic units.

   [1mThe implicit page trap[0m
       An [4mimplicit[24m [4mpage[24m [4mtrap[24m always exists  in  the  top‐level  diversion;  it
       works like a trap in some ways but not others.  Its purpose is to eject
       the  current page and start the next one.  It has no name, so it cannot
       be moved or deleted with [1mwh [22mor [1mch [22mrequests.   You  cannot  hide  it  by
       placing  another trap at its location, and can move it only by redefin‐
       ing the page length with [1m.pl[22m.  Its operation is suppressed when  verti‐
       cal page traps are disabled with the [1mvpt [22mrequest.

[1mDiversions[0m
       In [4mroff[24m systems it is possible to format text as if for output, but in‐
       stead of writing it immediately, one can [4mdivert[24m the formatted text into
       a named storage area.  It is retrieved later by specifying its name af‐
       ter  a  control character.  The same name space is used for such [4mdiver‐[0m
       [4msions[24m as for strings and macros; see section “Identifiers” above.  Such
       text is sometimes said to be “stored in a macro”, but this coinage  ob‐
       scures the important distinction between macros and strings on one hand
       and  diversions  on the other; the former store [4munformatted[24m input text,
       and the latter capture [4mformatted[24m output.  Diversions also do not inter‐
       pret arguments.  Applications of diversions include “keeps” (preventing
       a page break from occurring at an inconvenient place by forcing  a  set
       of  output  lines to be set as a group), footnotes, tables of contents,
       and indices.  For orthogonality it is said that GNU  [4mtroff[24m  is  in  the
       [4mtop‐level[24m  [4mdiversion[24m if no diversion is active (that is, formatted out‐
       put is being “diverted” immediately to the output device.

       Dereferencing an undefined diversion will create an empty one  of  that
       name  and  cause a warning in category [1mmac [22mto be emitted.  (see section
       “Warnings” in [4mtroff[24m(1)).  A diversion does not exist for the purpose of
       testing with the [1md [22mconditional operator until  its  initial  definition
       ends (see subsection “Conditional expressions” above).

       The  [1mdi  [22mrequest creates a diversion, including any partially collected
       line.  [1mda [22mappends to a diversion, creating one if it does  not  already
       exist.   If the diversion’s name already exists as an alias, the target
       of the alias is replaced or appended to; see section  “Strings”  above.
       [1mbox  [22mand  [1mboxa  [22mworks  similarly, but ignore partially collected lines.
       Call any of these macros again without an argument to  end  the  diver‐
       sion.

       Diversions  can be nested.  The registers [1m.d[22m, [1m.z[22m, [1mdn[22m, and [1mdl [22mreport in‐
       formation about the current (or last closed) diversion.  [1m.h [22mis meaning‐
       ful in diversions, including the top level.

       The [1m\!  [22mand [1m\?  [22mescape sequences and [1moutput [22mrequest escape from  a  di‐
       version,  the  first two to the enclosing level and the last to the top
       level.  This facility is termed [4mtransparent[24m [4membedding[24m.

       The [1masciify [22mand [1munformat [22mrequests reprocess diversions.

[1mPunning names[0m
       Macros, strings, and diversions share a name space; see section  “Iden‐
       tifiers”  above.  Internally, the same mechanism is used to store them.
       You can thus call a macro with string  interpolation  syntax  and  vice
       versa.   Interpolating a string does not hide existing macro arguments.
       The sequence [1m\\ [22mcan be placed at the end of a line in a  macro  defini‐
       tion or, within a macro definition, immediately after the interpolation
       of a macro as a string to suppress the effect of a newline.

[1mEnvironments[0m
       Environments store most of the parameters that control text processing.
       A default environment named “[1m0[22m” exists when [4mtroff[24m starts up; it is mod‐
       ified by formatting‐related requests and escape sequences.

       You  can  create  new  environments and switch among them.  Only one is
       current at any given time.  Active environments  are  managed  using  a
       [4mstack,[24m  a  data  structure supporting “push” and “pop” operations.  The
       current environment is at the top of the stack.  The  same  environment
       name  can be pushed onto the stack multiple times, possibly interleaved
       with others.  Popping the environment stack does not destroy  the  cur‐
       rent environment; it remains accessible by name and can be made current
       again  by  pushing  it  at any time.  Environments cannot be renamed or
       deleted, and can only be modified when current.  To inspect  the  envi‐
       ronment stack, use the [1mpev [22mrequest; see section “Debugging” below.

       Environments store the following information.

       • a partially collected line, if any

       • data  about  the most recently output glyph and line (registers [1m.cdp[22m,
         [1m.cht[22m, [1m.csk[22m, [1m.n[22m, [1m.w[22m)

       • typeface parameters (size, family, style, height  and  slant,  inter‐
         word and inter‐sentence space sizes)

       • page  parameters  (line  length, title length, vertical spacing, line
         spacing, indentation, line numbering, centering, right‐alignment, un‐
         derlining, hyphenation parameters)

       • filling enablement; adjustment enablement and mode

       • tab stops; tab, leader, escape, control,  no‐break  control,  hyphen‐
         ation, and margin characters

       • input line traps

       • stroke and fill colors

       The [1mev [22mrequest pushes to and pops from the environment stack, while [1mevc[0m
       copies a named environment’s contents to the current one.

[1mUnderlining[0m
       In  [4mRUNOFF[24m  (see  [4mroff[24m(7)),  underlining, even of lengthy passages, was
       straightforward because only fixed‐pitch  printing  devices  were  tar‐
       geted.   Typesetter  output  posed a greater challenge.  There exists a
       [4mgroff[24m request [1m.ul [22m(see above) that underlines subsequent  source  lines
       on  terminal  devices,  but  on  typesetters, it selects an italic font
       style instead.  The [4mms[24m macro package (see [4mgroff_ms[24m(7)) offers  a  macro
       [1m.UL[22m,  but  it  too produces the desired effect only on typesetters, and
       has other limitations.

       One could adapt [4mms[24m’s approach to the construction of a  macro  as  fol‐
       lows.
              .de UNDERLINE
              . ie n \\$1\f[I]\\$2\f[P]\\$3
              . el \\$1\Z'\\$2'\v'.25m'\D'l \w'\\$2'u 0'\v'-.25m'\\$3
              ..
       If  [4mdoclifter[24m(1)  makes  trouble,  change the macro name [1mUNDERLINE [22minto
       some 2‐letter word, like [1mUl[22m.  Moreover, change the form of the font se‐
       lection escape sequence from [1m\f[P] [22mto [1m\fP[22m.

   [1mUnderlining without macro definitions[0m
       If one does not want to use macro  definitions,  e.g.,  when  [4mdoclifter[0m
       gets lost, use the following.
              .ds u1 before
              .ds u2 in
              .ds u3 after
              .ie n \*[u1]\f[I]\*[u2]\f[P]\*[u3]
              .el \*[u1]\Z'\*[u2]'\v'.25m'\D'l \w'\*[u2]'u 0'\v'-.25m'\*[u3]
       When using [4mdoclifter[24m, it might be necessary to change syntax forms such
       as  [1m\[xy]  [22mand [1m\*[xy] [22mto those supported by AT&T [4mtroff[24m: [1m\*(xy [22mand [1m\(xy[22m,
       and so on.

       Then these lines could look like
              .ds u1 before
              .ds u2 in
              .ds u3 after
              .ie n \*[u1]\fI\*(u2\fP\*(u3
              .el \*(u1\Z'\*(u2'\v'.25m'\D'l \w'\*(u2'u 0'\v'-.25m'\*(u3

       The result looks like
              before _i_n after

   [1mUnderlining by overstriking with \(ul[0m
       The [1m\z [22mescape sequence writes a glyph without advancing the drawing po‐
       sition, enabling overstriking.  Thus, [1m\z[4m[22mc[24m[1m\(ul [22mformats [4mc[24m with an  under‐
       rule  glyph  on  top of it.  Video terminals implement the underrule by
       setting a character cell’s underline attribute, so this technique works
       in both [4mnroff[24m and [4mtroff[24m modes.

       Long words may then look intimidating in the input;  a  clarifying  ap‐
       proach  might  be  to  use  the input line continuation escape sequence
       [1m\[4m[22mnewline[24m to place each underlined character  on  its  own  input  line.
       Thus,
              .nf
              \&\fB: ${\fIvar\fR\c
              \zo\(ul\
              \zp\(ul\c
              \&\fIvalue\fB}
              .fi
       produces
              [1m: ${[4m[22mvar[24mo_p_[4mvalue[24m[1m}[0m
       as output.

[1mCompatibility mode[0m
       The  differences  between the [4mroff[24m language recognized by GNU [4mtroff[24m and
       that of AT&T [4mtroff[24m, as well as the device, font, and device‐independent
       intermediate output formats described by CSTR  #54  are  documented  in
       [4mgroff_diff[24m(7).  [4mgroff[24m provides an AT&T compatibility mode.  The [1m.cp [22mre‐
       quest  and  registers  [1m.C  [22mand  [1m.cp [22mset and test the enablement of this
       mode.

[1mDebugging[0m
       Preprocessors use the [1m.lf [22mrequest to preserve the  identities  of  line
       numbers and names of input files.  [4mgroff[24m emits a variety of error diag‐
       nostics and supports several categories of warning; the output of these
       can  be  selectively  suppressed with [1m.warn [22m(and see the [1m-E[22m, [1m-w[22m, and [1m-W[0m
       options of [4mtroff[24m(1)).  A trace  of  the  formatter’s  input  processing
       stack  can  be  emitted  when  errors  or  warnings  occur  by means of
       [4mtroff[24m(1)’s [1m-b [22moption, or produced on demand  with  the  [1m.backtrace  [22mre‐
       quest.   [1m.tm[22m,  [1m.tmc[22m, and [1m.tm1 [22mcan be used to emit customized diagnostic
       messages or for instrumentation while  troubleshooting.   [1m.ex  [22mand  [1m.ab[0m
       cause  early  termination  with successful and error exit codes respec‐
       tively, to halt further processing when continuing would be  fruitless.
       Examine  the  state  of the formatter with requests that write lists of
       defined  names—macros,  strings,  and  diversions—([1m.pm[22m);   environments
       ([1m.pev[22m),  registers  ([1m.pnr[22m), and page location traps ([1m.ptr[22m) to the stan‐
       dard error stream.

[1mAuthors[0m
       This document was written by by Trent A. Fisher, Werner Lemberg, and G.
       Branden Robinson ⟨g.branden.robinson@gmail.com⟩.  Section “Underlining”
       was primarily written by Bernd Warken ⟨groff-bernd.warken-72@web.de⟩.

[1mSee also[0m
       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher  and  Werner
       Lemberg,  is the primary [4mgroff[24m manual.  You can browse it interactively
       with “info groff”.

       “Troff User’s Manual” by Joseph F. Ossanna, 1976 (revised by  Brian  W.
       Kernighan,  1992),  AT&T  Bell Laboratories Computing Science Technical
       Report No. 54, widely called simply “CSTR #54”, documents the language,
       device and font description file formats, and device‐independent output
       format referred to collectively in [4mgroff[24m documentation as “AT&T [4mtroff[24m”.

       “A Typesetter‐independent TROFF” by Brian W. Kernighan, 1982, AT&T Bell
       Laboratories Computing Science Technical Report No. 97 (CSTR #97), pro‐
       vides additional insights into the device  and  font  description  file
       formats and device‐independent output format.

       [4mgroff[24m(1)
              is  the  preferred interface to the [4mgroff[24m system; it manages the
              pipeline that carries a source document  through  preprocessors,
              the  [4mtroff[24m formatter, and an output driver to viewable or print‐
              able form.  It also exhaustively lists the  man  pages  provided
              with the GNU [4mroff[24m system.

       [4mgroff_char[24m(7)
              discusses  character encoding issues, escape sequences that pro‐
              duce glyphs, and enumerates [4mgroff[24m’s predefined special character
              escape sequences.

       [4mgroff_diff[24m(7)
              covers differences between the GNU [4mtroff[24m formatter,  its  device
              and font description file formats, its device‐independent output
              format, and those of AT&T [4mtroff[24m, whose design it reimplements.

       [4mgroff_font[24m(5)
              describes  the formats of the files that describe devices ([4mDESC[24m)
              and fonts.

       [4mgroff_tmac[24m(5)
              surveys macro packages provided with [4mgroff[24m, describes how  docu‐
              ments  can  take  advantage  of them, offers guidance on writing
              macro packages and using diversions, and includes historical in‐
              formation on macro package naming conventions.

       [4mroff[24m(7)
              presents a detailed history of [4mroff[24m systems and summarizes  con‐
              cepts common to them.

groff 1.23.0                      5 July 2023                         [4mgroff[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_char[24m(7)          Miscellaneous Information Manual          [4mgroff_char[24m(7)

[1mName[0m
       groff_char - GNU [4mroff[24m special character and glyph repertoire

[1mDescription[0m
       The  GNU  [4mroff[24m typesetting system has a large glyph repertoire suitable
       for production of varied literary, professional, technical, and  mathe‐
       matical  documents.  [4mgroff[24m works with [4mcharacters;[24m an output device ren‐
       ders [4mglyphs.[24m  [4mgroff[24m’s input character set is restricted to that defined
       by the standards ISO Latin‐1 (ISO 8859‐1) and CCSID  “code  page”  1047
       (an  EBCDIC  arrangement of Latin‐1).  For ease of document maintenance
       in UTF‐8 environments, it is advisable to use only  the  Unicode  basic
       Latin  code  points,  a subset of all of the foregoing historically re‐
       ferred to as US‐ASCII,  which  has  only  94  visible,  printable  code
       points.   In  [4mgroff,[24m these are termed [4mordinary[24m [4mcharacters.[24m  Often, many
       more are desired in output.

       AT&T [4mtroff[24m in the 1970s faced a similar problem: the available typeset‐
       ter’s glyph repertoire differed from that of the  computers  that  con‐
       trolled  it.  [4mtroff[24m’s solution was a form of escape sequence known as a
       [4mspecial[24m [4mcharacter[24m to access several dozen additional  glyphs  available
       in  the  fonts  prepared  for  mounting  in the phototypesetter.  These
       glyphs were mapped onto a two‐character name  space  for  a  degree  of
       mnemonic  convenience; for example, the escape sequence [1m\(aa [22mencoded an
       acute accent and [1m\(sc [22ma section sign.

       [4mgroff[24m has lifted historical [4mroff[24m limitations on special character  name
       lengths,  but  recognizes and retains compatibility with the historical
       names.  [4mgroff[24m expands the lexicon of glyphs available by name and  per‐
       mits  users to define their own special character escape sequences with
       the [1mchar [22mrequest.  Special character names are [4mgroff[24m  identifiers;  see
       section  “Identifiers”  in  [4mgroff[24m(7).   Our  discussion  uses the terms
       “glyph name” and “special character name” interchangeably; we assume no
       character translations or redefinitions.

       This document lists all of the glyph names predefined by  [4mgroff[24m’s  font
       description  files and presents the systematic notation by which it en‐
       ables access to arbitrary Unicode code points and construction of  com‐
       posite  glyphs.   Glyphs  listed may be unavailable, or may vary in ap‐
       pearance, depending on the output device and font chosen when the  page
       was formatted.  This page was rendered for device [1mutf8 [22musing font [1mR[22m.

       A  few escape sequences that are not [4mgroff[24m special characters also pro‐
       duce glyphs; these exist for syntactical or  historical  reasons.   [1m\'[22m,
       [1m\`[22m,  [1m\-[22m, and [1m\_ [22mare translated on input to the special character escape
       sequences [1m\[aa][22m, [1m\[ga][22m, [1m\[-][22m, and [1m\[ul][22m, respectively.  Others  include
       [1m\\[22m,  [1m\.  [22m(backslash‐dot), and [1m\e[22m; see [4mgroff[24m(7).  A small number of spe‐
       cial characters represent glyphs that are not encoded in Unicode; exam‐
       ples include the baseline rule [1m\[ru] [22mand the Bell System logo [1m\[bs].[0m

       In [4mgroff[24m, you can test output device support for any  character  (ordi‐
       nary or special) with the conditional expression operator “[1mc[22m”.
              .ie c \[bs] \{Welcome to the \[bs] Bell System;
              did you get the Wehrmacht helmet or the Death Star?\}
              .el No Bell System logo.

       For  brevity  in the remainder of this document, we shall refer to sys‐
       tems conforming to the ISO 646:1991 IRV, ISO 8859, or ISO 10646  (“Uni‐
       code”) character encoding standards as “ISO” systems, and those employ‐
       ing  IBM code page 1047 as “EBCDIC” systems.  That said, EBCDIC systems
       that support [4mgroff[24m are known to also support UTF‐8.

       While [4mgroff[24m accepts eight‐bit encoded input, not all such  code  points
       are  valid  as  input.  On ISO platforms, character codes 0, 11, 13–31,
       and 128–159 are invalid.  (This is all C0 and C1  controls  except  for
       SOH  through  LF  [Control+A  to  Control+J],  and FF [Control+L].)  On
       EBCDIC platforms, 0, 8–9, 11, 13–20,  23–31,  and  48–63  are  invalid.
       Some  of  these  code  points  are used by [4mgroff[24m for internal purposes,
       which is one reason it does not support UTF‐8 natively.

   [1mFundamental character set[0m
       The ordinary characters catalogued above, plus the space, tab, newline,
       and leader (Control+A), form the fundamental character  set  for  [4mgroff[0m
       input;  anything  in the language, even over one million code points in
       Unicode, can be expressed using it.  On ISO systems, code points in the
       range 33–126 comprise a common set of printable glyphs in  all  of  the
       aforementioned  ISO character encoding standards.  It is this character
       set and (with  some  noteworthy  exceptions)  the  corresponding  glyph
       repertoire  for  which  AT&T [4mtroff[24m was implemented.  On EBCDIC systems,
       printable characters are in the range 66–201 and 203–254; those without
       counterparts in the ISO range 33–126 are discussed in the next  subsec‐
       tion.

       All of the following characters map to glyphs as you would expect.
           ┌───────────────────────────────────────────────────────────┐
           │ ! # $ % & ( ) * + , . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ │
           │ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ ] _ │
           │ a b c d e f g h i j k l m n o p q r s t u v w x y z { | } │
           └───────────────────────────────────────────────────────────┘
       The  remaining ordinary characters surprise computing professionals and
       others intimately familiar with the ISO character encodings.   The  de‐
       velopers of AT&T [4mtroff[24m chose mappings for them that would be useful for
       typesetting  technical literature in a broad range of scientific disci‐
       plines: Bell Labs used the system for preparation of AT&T’s patent fil‐
       ings with the U.S. government.  Further, the prevailing  character  en‐
       coding  standard  in  the 1970s, USAS X3.4‐1968 (“ASCII”), deliberately
       supported semantic ambiguity at some code points, and outright  substi‐
       tution  at  several others, to suit the localization demands of various
       national standards bodies.

       The table below presents the seven exceptional code points  with  their
       typical  keycap  engravings, their glyph mappings and semantics in [4mroff[0m
       systems, and the escape sequences producing  the  Unicode  basic  Latin
       character they replace.  The first, the neutral double quote, is a par‐
       tial  exception  because  it  does represent itself, but since the [4mroff[0m
       language also uses it to quote macro arguments, [4mgroff[24m supports  a  spe‐
       cial character escape sequence as an alternative form so that the glyph
       can be easily included in macro arguments without requiring the user to
       master  the  quoting  rules  that  AT&T [4mtroff[24m required in that context.
       (Some requests, like [1mds[22m, also treat [1m" [22mnon‐literally.)  Furthermore, not
       all of the special character escape  sequences  are  portable  to  AT&T
       [4mtroff[24m  and all of its descendants; these [4mgroff[24m extensions are presented
       using its special character form [1m\[][22m, whereas portable special  charac‐
       ter  escape  sequences are shown in the traditional [1m\( [22mform.  [1m\- [22mand [1m\e[0m
       are portable to all known [4mtroff[24ms.  [1m\e [22mmeans “the glyph of  the  current
       escape character”; it therefore can produce unexpected output if the [1mec[0m
       request is used.  On devices with a limited glyph repertoire, glyphs in
       the  “keycap” and “appearance” columns on the same row of the table may
       look identical; except for the neutral double quote, this will  [4mnot[24m  be
       the  case  on more‐capable devices.  Review your document using as many
       different output devices as possible.

       ┌───────────────────────────────────────────────────────────────────┐
       │ Keycap   Appearance and meaning   Special character and meaning   │
       ├───────────────────────────────────────────────────────────────────┤
       │ "        " neutral double quote   \[dq] neutral double quote      │
       │ '        ’ closing single quote   \[aq] neutral apostrophe        │
       │ -        ‐ hyphen                 \- or \[-] minus sign/Unix dash │
       │ \        (escape character)       \e or \[rs] reverse solidus     │
       │ ^        ˆ modifier circumflex    \(ha circumflex/caret/“hat”     │
       │ `        ‘ opening single quote   \(ga grave accent               │
       │ ~        ˜ modifier tilde         \(ti tilde                      │
       └───────────────────────────────────────────────────────────────────┘

       The hyphen‐minus is a particularly  unfortunate  case  of  overloading.
       Its awkward name in ISO 8859 and later standards reflects the many dis‐
       tinguishable  purposes  to  which it had already been put by the 1980s,
       including a hyphen, a minus sign, and (alone or in  repetition)  dashes
       of varying widths.  For best results in [4mroff[24m systems, use the “[1m-[22m” char‐
       acter  in input outside an escape sequence [4monly[24m to mean a hyphen, as in
       the phrase “long‐term”.  For a minus sign in running  text  or  a  Unix
       command‐line option dash, use [1m\- [22m(or [1m\[-] [22min [4mgroff[24m if you find it helps
       the  clarity  of the source document).  (Another minus sign, for use in
       mathematical equations, is available as [1m\[mi][22m).  AT&T  [4mtroff[24m  supported
       em‐dashes as [1m\(em[22m, as does [4mgroff[24m.

       The  special  character escape sequence for the apostrophe as a neutral
       single quote is typically needed  only  in  technical  content;  typing
       words like “can’t” and “Anne’s” in a natural way will render correctly,
       because  in ordinary prose an apostrophe is typeset either as a closing
       single quotation mark or as a neutral single quote,  depending  on  the
       capabilities  of the output device.  By contrast, special character es‐
       cape sequences should be used for quotation marks unless portability to
       limited or historical [4mtroff[24m implementations is necessary; on those sys‐
       tems, the input convention is to pair the grave accent with  the  apos‐
       trophe  for  single  quotes,  and  to double both characters for double
       quotes.  AT&T [4mtroff[24m defined no special characters for  quotation  marks
       or  the apostrophe.  Repeated single quotes (‘‘thus’’) will be visually
       distinguishable from double quotes (“thus”) on  terminal  devices,  and
       perhaps on others (depending on the font selected).
        ┌─────────────────────────────────────────────────────────────────┐
        │ AT&T [4mtroff[24m input          recommended [4mgroff[24m input               │
        ├─────────────────────────────────────────────────────────────────┤
        │ A Winter's Tale           A Winter's Tale                       │
        │ `U.K. outer quotes'       \[oq]U.K. outer quotes\[cq]           │
        │ `U.K. ``inner'' quotes'   \[oq]U.K. \[lq]inner\[rq] quotes\[cq] │
        │ ``U.S. outer quotes''     \[lq]U.S. outer quotes\[rq]           │
        │ ``U.S. `inner' quotes''   \[lq]U.S. \[oq]inner\[cq] quotes\[rq] │
        └─────────────────────────────────────────────────────────────────┘
       If  you frequently require quotation marks in your document, see if the
       macro package you’re using supplies strings  or  macros  to  facilitate
       quotation, or define them yourself (except in man pages).

       Using Unicode basic Latin characters to compose boxes and lines is ill‐
       advised.   [4mroff[24m  systems have special characters for drawing horizontal
       and vertical lines; see subsection “Rules and lines” below.  Preproces‐
       sors like [4mtbl[24m(1) and [4mpic[24m(1) draw boxes and will produce the best possi‐
       ble output for the device, falling back to basic Latin glyphs only when
       necessary.

   [1mEight‐bit encodings and Latin‐1 supplement[0m
       ISO 646 is a seven‐bit code encoding 128 code points;  eight‐bit  codes
       are  twice the size.  ISO 8859‐1 and code page 1047 allocated the addi‐
       tional space to what Unicode calls “C1 controls”  (control  characters)
       and  the  “Latin‐1  supplement”.  The C1 controls are neither printable
       nor usable as [4mgroff[24m input.

       Two Latin‐1 supplement  characters  are  handled  specially  on  input.
       [4mtroff[24m never produces them as output.

       NBSP   encodes  a  no‐break  space;  it is mapped to [1m\~[22m, the adjustable
              non‐breaking space escape sequence.

       SHY    encodes a soft hyphen; it is mapped to [1m\%[22m, the hyphenation  con‐
              trol escape sequence.

       The  remaining  characters  in  the  Latin‐1 supplement represent them‐
       selves.  Although they can be specified directly with the  keyboard  on
       systems configured to use Latin‐1 as the character encoding, it is more
       portable,  both to other [4mroff[24m systems and to UTF‐8 environments, to use
       their special character escape sequences, shown below.  The  glyph  de‐
       scriptions we use are non‐standard in some cases, for brevity.

       ¡  \[r!] inverted exclamation mark     Ñ  \[~N] N tilde
       ¢  \[ct] cent sign                     Ò  \[`O] O grave
       £  \[Po] pound sign                    Ó  \['O] O acute
       ¤  \[Cs] currency sign                 Ô  \[^O] O circumflex
       ¥  \[Ye] yen sign                      Õ  \[~O] O tilde
       ¦  \[bb] broken bar                    Ö  \[:O] O dieresis
       §  \[sc] section sign                  ×  \[mu] multiplication sign
       ¨  \[ad] dieresis accent               Ø  \[/O] O slash
       ©  \[co] copyright sign                Ù  \[`U] U grave
       ª  \[Of] feminine ordinal indicator    Ú  \['U] U acute
       «  \[Fo] left double chevron           Û  \[^U] U circumflex
       ¬  \[no] logical not                   Ü  \[:U] U dieresis
       ®  \[rg] registered sign               Ý  \['Y] Y acute
       ¯  \[a-] macron accent                 Þ  \[TP] uppercase thorn
       °  \[de] degree sign                   ß  \[ss] lowercase sharp s
       ±  \[+-] plus‐minus                    à  \[`a] a grave
       ²  \[S2] superscript two               á  \['a] a acute
       ³  \[S3] superscript three             â  \[^a] a circumflex
       ´  \[aa] acute accent                  ã  \[~a] a tilde
       µ  \[mc] micro sign                    ä  \[:a] a dieresis
       ¶  \[ps] pilcrow sign                  å  \[oa] a ring
       ·  \[pc] centered period               æ  \[ae] ae ligature
       ¸  \[ac] cedilla accent                ç  \[,c] c cedilla
       ¹  \[S1] superscript one               è  \[`e] e grave
       º  \[Om] masculine ordinal indicator   é  \['e] e acute
       »  \[Fc] right double chevron          ê  \[^e] e circumflex
       ¼  \[14] one quarter symbol            ë  \[:e] e dieresis
       ½  \[12] one half symbol               ì  \[`i] i grave
       ¾  \[34] three quarters symbol         í  \['i] e acute
       ¿  \[r?] inverted question mark        î  \[^i] i circumflex
       À  \[`A] A grave                       ï  \[:i] i dieresis
       Á  \['A] A acute                       ð  \[Sd] lowercase eth
       Â  \[^A] A circumflex                  ñ  \[~n] n tilde
       Ã  \[~A] A tilde                       ò  \[`o] o grave
       Ä  \[:A] A dieresis                    ó  \['o] o acute
       Å  \[oA] A ring                        ô  \[^o] o circumflex
       Æ  \[AE] AE ligature                   õ  \[~o] o tilde
       Ç  \[,C] C cedilla                     ö  \[:o] o dieresis
       È  \[`E] E grave                       ÷  \[di] division sign
       É  \['E] E acute                       ø  \[/o] o slash
       Ê  \[^E] E circumflex                  ù  \[`u] u grave
       Ë  \[:E] E dieresis                    ú  \['u] u acute
       Ì  \[`I] I grave                       û  \[^u] u circumflex
       Í  \['I] I acute                       ü  \[:u] u dieresis
       Î  \[^I] I circumflex                  ý  \['y] y acute
       Ï  \[:I] I dieresis                    þ  \[Tp] lowercase thorn
       Ð  \[-D] uppercase eth                 ÿ  \[:y] y dieresis

   [1mSpecial character escape forms[0m
       Glyphs  that lack a character code in the basic Latin repertoire to di‐
       rectly represent them are entered by one of several  special  character
       escape forms.  Such glyphs can be simple or composite, and accessed ei‐
       ther  by  name or numerically by code point.  Code points and combining
       properties are determined  by  character  encoding  standards,  whereas
       glyph names as used here originated in AT&T [4mtroff[24m special character es‐
       cape  sequences.  Predefined glyph names use only characters in the ba‐
       sic Latin repertoire.

       [1m\([4m[22mgl[24m   is a special character escape sequence for the  glyph  with  the
              two‐character  name  [4mgl[24m.   This is the original syntax form sup‐
              ported by AT&T [4mtroff[24m.  The acute accent, [1m\(aa[22m, is an example.

       [1m\C'[4m[22mglyph‐name[24m[1m'[0m
              is a special character escape sequence for [4mglyph‐name[24m, which can
              be of arbitrary length.  The delimiter, shown here as a  neutral
              apostrophe,  can  be  any character not occurring in [4mglyph‐name[24m.
              This syntax form was introduced in later versions  of  AT&T  de‐
              vice‐independent  [4mtroff[24m.  The foregoing acute accent example can
              be expressed as [1m\C'aa'[22m.

       [1m\[[4m[22mglyph‐name[24m[1m][0m
              is a special character escape sequence for [4mglyph‐name[24m, which can
              be of arbitrary length but must not  contain  a  closing  square
              bracket  “[1m][22m”.   (No glyph names predefined by [4mgroff[24m employ “[1m][22m”.)
              The foregoing acute accent example can be expressed in [4mgroff[24m  as
              [1m\[aa][22m.

       [1m\C'[4m[22mc[24m[1m' [22mand [1m\[[4m[22mc[24m[1m] [22mare not synonyms for the ordinary character “[4mc[24m”, but re‐
       quest  the  special  character  named “[1m\[4m[22mc[24m”.  For example, “[1m\[a][22m” is not
       “a”, but rather a special character with the internal glyph name  (used
       in  font  description files and diagnostic messages) [1m\a[22m, which is typi‐
       cally undefined.  The only such glyph name [4mgroff[24m predefines is the  mi‐
       nus sign, which can therefore be accessed as [1m\C'-' [22mor [1m\[-][22m.

       [1m\[[4m[22mbase‐char[24m [4mcomposite‐1[24m [4mcomposite‐2[24m ... [4mcomposite‐n[24m[1m][0m
              is a composite glyph.  Glyphs like a lowercase “e” with an acute
              accent, as in the word “café”, can be expressed as [1m\[e aa][22m.  See
              subsection “Accents” below for a table of combining glyph names.

       Unicode  encodes  far  more  characters than [4mgroff[24m has glyph names for;
       special character escape forms based on numerical  code  points  enable
       access  to  any  of them.  Frequently used glyphs or glyph combinations
       can be stored in strings, and new glyph names can  be  created  [4mad[24m  [4mhoc[0m
       with the [1mchar [22mrequest; see [4mgroff[24m(7).

       [1m\[u[4m[22mnnnn[24m[[4mn[24m[[4mn[24m]][1m][0m
              is  a  Unicode  numeric  special character escape sequence.  Any
              Unicode code point can be accessed with four to six  hexadecimal
              digits,  with  hexadecimal  letters  accepted  in uppercase form
              only.  Thus, [1m\[u02DA] [22maccesses the (spacing) ring  accent,  pro‐
              ducing “˚”.

       Unicode  code  points can be composed as well; when they are, GNU [4mtroff[0m
       requires NFD (Normalization Form D), where all Unicode glyphs are maxi‐
       mally decomposed.  (Exception: precomposed characters  in  the  Latin‐1
       supplement described above are also accepted.  Do not count on this ex‐
       ception  remaining  in  a future GNU [4mtroff[24m that accepts UTF‐8 input di‐
       rectly.)   Thus,  GNU  [4mtroff[24m  accepts  “caf[1m\['e][22m”,  “caf[1m\[e  aa][22m”,  and
       “caf[1m\[u0065_0301][22m”,  as ways to input “café”.  (Due to its legacy 8‐bit
       encoding compatibility, at present it also accepts “caf[1m\[u00E9][22m” on ISO
       Latin‐1 systems.)

       [1m\[u[4m[22mbase‐char[24m[[1m_[4m[22mcombining‐component[24m]...]
              constructs a composite glyph from Unicode numeric special  char‐
              acter  escape  sequences.  The code points of the base glyph and
              the combining components are each expressed in hexadecimal, with
              an   underscore   ([1m_[22m)   separating   each   component.     Thus,
              [1m\[u006E_0303] [22mproduces “ñ”.

       [1m\[char[4m[22mnnn[24m[1m][0m
              expresses an eight‐bit code point where [4mnnn[24m is the code point of
              the  character, a decimal number between 0 and 255 without lead‐
              ing zeroes.  This legacy numeric special  character  escape  se‐
              quence  is  used  to map characters onto glyphs via the [1mtrin [22mre‐
              quest in macro files loaded by [4mgrotty[24m(1).

[1mGlyph tables[0m
       In this section, [4mgroff[24m’s glyph name repertoire is presented in  tabular
       form.  The meanings of the columns are as follows.

       [1mOutput  [22mshows the glyph as it appears on the device used to render this
               document;  although  it  can  have a notably different shape on
               other devices (and is subject to user‐directed translation  and
               replacement), [4mgroff[24m attempts reasonable equivalency on all out‐
               put devices.

       [1mInput   [22mshows  the  [4mgroff[24m character (ordinary or special) that normally
               produces the glyph.   Some  code  points  have  multiple  glyph
               names.

       [1mUnicode [22mis the code point notation for the glyph or combining glyph se‐
               quence  as  described  in  subsection “Special character escape
               forms” above.  It corresponds to the standard notation for Uni‐
               code short identifiers such that [4mgroff[24m’s [1mu[4m[22mnnnn[24m is equivalent to
               Unicode’s U+[4mnnnn[24m.

       [1mNotes   [22mdescribes the glyph, elucidating  the  mnemonic  value  of  the
               glyph name where possible.

               A  plus  sign  “+” indicates that the glyph name appears in the
               AT&T [4mtroff[24m user’s manual, CSTR #54 (1992 revision).  When using
               the AT&T special character syntax [1m\([4m[22mxx[24m, widespread  portability
               can be expected from such names.

               Entries  marked  with “***” denote glyphs used for mathematical
               purposes.  On typesetting devices, such  glyphs  are  typically
               drawn  from  a  [4mspecial[24m  font (see [4mgroff_font[24m(5)).  Often, such
               glyphs lack bold or italic style forms  or  have  metrics  that
               look incongruous in ordinary prose.  A few which are not uncom‐
               mon  in  running  text  have “text variants”, which should work
               better in that context.  Conversely, a handful of  glyphs  that
               are  normally  drawn from a text font may be required in mathe‐
               matical equations.  Both sets of exceptions are  noted  in  the
               tables  where  they appear (“Logical symbols” and “Mathematical
               symbols”).

   [1mBasic Latin[0m
       Apart from basic Latin characters with special mappings,  described  in
       subsection  “Fundamental  character  set”  above,  a few others in that
       range have special character glyph names.  These were defined for  ease
       of  input on non‐U.S. keyboards lacking keycaps for them, or for symme‐
       try with other special character glyph names serving a similar purpose.

       The vertical bar is overloaded; the [1m\[ba] [22mand  [1m\[or]  [22mescape  sequences
       may  render  differently.   See subsection “Mathematical symbols” below
       for special variants of the plus,  minus,  and  equals  signs  normally
       drawn from this range.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       "        \[dq]   u0022     neutral double quote
       #        \[sh]   u0023     number sign
       $        \[Do]   u0024     dollar sign
       '        \[aq]   u0027     apostrophe, neutral single quote
       /        \[sl]   u002F     slash, solidus +
       @        \[at]   u0040     at sign
       [        \[lB]   u005B     left square bracket
       \        \[rs]   u005C     reverse solidus
       ]        \[rB]   u005D     right square bracket
       ^        \[ha]   u005E     circumflex, caret, “hat”
       {        \[lC]   u007B     left brace
       |        |       u007C     bar
       |        \[ba]   u007C     bar
       |        \[or]   u007C     bitwise or +
       }        \[rC]   u007D     right brace
       ~        \[ti]   u007E     tilde

   [1mSupplementary Latin letters[0m
       Historically,  [1m\[ss] [22mcould be considered a ligature of “sz”.  An upper‐
       case form is available as [1m\[u1E9E][22m, but in the German language it is of
       specialized use; ß does [4mnot[24m normally  uppercase‐transform  to  it,  but
       rather  to  “SS”.   “Lowercase  f with hook” is also used as a function
       symbol; see subsection “Mathematical symbols” below.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       Ð        \[-D]   u00D0     uppercase eth
       ð        \[Sd]   u00F0     lowercase eth
       Þ        \[TP]   u00DE     uppercase thorn
       þ        \[Tp]   u00FE     lowercase thorn
       ß        \[ss]   u00DF     lowercase sharp s
       ı        \[.i]   u0131     i without tittle
       ȷ        \[.j]   u0237     j without tittle
       ƒ        \[Fn]   u0192     lowercase f with hook, function
       Ł        \[/L]   u0141     L with stroke
       ł        \[/l]   u0142     l with stroke
       Ø        \[/O]   u00D8     O with stroke
       ø        \[/o]   u00F8     o with stroke

   [1mLigatures and digraphs[0m
       Output   Input   Unicode           Notes
       ────────────────────────────────────────────────────────────────────────
       ff       \[ff]   u0066_0066        ff ligature +
       fi       \[fi]   u0066_0069        fi ligature +
       fl       \[fl]   u0066_006C        fl ligature +
       ffi      \[Fi]   u0066_0066_0069   ffi ligature +
       ffl      \[Fl]   u0066_0066_006C   ffl ligature +
       Æ        \[AE]   u00C6             AE ligature
       æ        \[ae]   u00E6             ae ligature
       Œ        \[OE]   u0152             OE ligature
       œ        \[oe]   u0153             oe ligature
       Ĳ        \[IJ]   u0132             IJ digraph
       ĳ        \[ij]   u0133             ij digraph

   [1mAccents[0m
       Normally, the formatting of a special character  advances  the  drawing
       position as an ordinary character does.  [4mgroff[24m’s [1mcomposite [22mrequest des‐
       ignates  a  special  character  as combining.  The [4mcomposite.tmac[24m macro
       file, loaded automatically by the default [4mtroffrc[24m, maps  the  following
       special  characters  to the combining characters shown below.  The non‐
       combining code point in parentheses is used when the special  character
       occurs in isolation (compare “[1mcaf\[e aa][22m” and “[1mcaf\[aa]e[22m”).

       Output   Input   Unicode         Notes
       ────────────────────────────────────────────────────────────────────────
       ˝        \[a"]   u030B (u02DD)   double acute accent
       ¯        \[a-]   u0304 (u00AF)   macron accent
       ˙        \[a.]   u0307 (u02D9)   dot accent
       ^        \[a^]   u0302 (u005E)   circumflex accent
       ´        \[aa]   u0301 (u00B4)   acute accent +
       `        \[ga]   u0300 (u0060)   grave accent +
       ˘        \[ab]   u0306 (u02D8)   breve accent
       ¸        \[ac]   u0327 (u00B8)   cedilla accent
       ¨        \[ad]   u0308 (u00A8)   dieresis accent
       ˇ        \[ah]   u030C (u02C7)   caron accent
       ˚        \[ao]   u030A (u02DA)   ring accent
       ~        \[a~]   u0303 (u007E)   tilde accent
       ˛        \[ho]   u0328 (u02DB)   hook accent

   [1mAccented characters[0m
       All  of these glyphs can be composed using combining glyph names as de‐
       scribed in subsection “Special character escape forms” above; the names
       below are short aliases for convenience.

       Output   Input   Unicode      Notes
       ────────────────────────────────────────────────────────────────────────
       Á        \['A]   u0041_0301   A acute
       Ć        \['C]   u0043_0301   C acute
       É        \['E]   u0045_0301   E acute
       Í        \['I]   u0049_0301   I acute
       Ó        \['O]   u004F_0301   O acute
       Ú        \['U]   u0055_0301   U acute
       Ý        \['Y]   u0059_0301   Y acute
       á        \['a]   u0061_0301   a acute
       ć        \['c]   u0063_0301   c acute
       é        \['e]   u0065_0301   e acute
       í        \['i]   u0069_0301   i acute
       ó        \['o]   u006F_0301   o acute
       ú        \['u]   u0075_0301   u acute
       ý        \['y]   u0079_0301   y acute

       Ä        \[:A]   u0041_0308   A dieresis
       Ë        \[:E]   u0045_0308   E dieresis
       Ï        \[:I]   u0049_0308   I dieresis
       Ö        \[:O]   u004F_0308   O dieresis
       Ü        \[:U]   u0055_0308   U dieresis
       Ÿ        \[:Y]   u0059_0308   Y dieresis
       ä        \[:a]   u0061_0308   a dieresis
       ë        \[:e]   u0065_0308   e dieresis
       ï        \[:i]   u0069_0308   i dieresis
       ö        \[:o]   u006F_0308   o dieresis
       ü        \[:u]   u0075_0308   u dieresis
       ÿ        \[:y]   u0079_0308   y dieresis

       Â        \[^A]   u0041_0302   A circumflex
       Ê        \[^E]   u0045_0302   E circumflex
       Î        \[^I]   u0049_0302   I circumflex
       Ô        \[^O]   u004F_0302   O circumflex
       Û        \[^U]   u0055_0302   U circumflex
       â        \[^a]   u0061_0302   a circumflex
       ê        \[^e]   u0065_0302   e circumflex
       î        \[^i]   u0069_0302   i circumflex
       ô        \[^o]   u006F_0302   o circumflex
       û        \[^u]   u0075_0302   u circumflex

       À        \[`A]   u0041_0300   A grave
       È        \[`E]   u0045_0300   E grave
       Ì        \[`I]   u0049_0300   I grave
       Ò        \[`O]   u004F_0300   O grave
       Ù        \[`U]   u0055_0300   U grave
       à        \[`a]   u0061_0300   a grave
       è        \[`e]   u0065_0300   e grave
       ì        \[`i]   u0069_0300   i grave
       ò        \[`o]   u006F_0300   o grave
       ù        \[`u]   u0075_0300   u grave

       Ã        \[~A]   u0041_0303   A tilde
       Ñ        \[~N]   u004E_0303   N tilde
       Õ        \[~O]   u004F_0303   O tilde
       ã        \[~a]   u0061_0303   a tilde
       ñ        \[~n]   u006E_0303   n tilde
       õ        \[~o]   u006F_0303   o tilde

       Š        \[vS]   u0053_030C   S caron
       š        \[vs]   u0073_030C   s caron
       Ž        \[vZ]   u005A_030C   Z caron
       ž        \[vz]   u007A_030C   z caron

       Ç        \[,C]   u0043_0327   C cedilla
       ç        \[,c]   u0063_0327   c cedilla

       Å        \[oA]   u0041_030A   A ring
       å        \[oa]   u0061_030A   a ring

   [1mQuotation marks[0m
       The neutral double quote, often  useful  when  documenting  programming
       languages,  is also available as a special character for convenient em‐
       bedding in macro arguments; see subsection “Fundamental character  set”
       above.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       „        \[Bq]   u201E     low double comma quote
       ‚        \[bq]   u201A     low single comma quote
       “        \[lq]   u201C     left double quote
       ”        \[rq]   u201D     right double quote
       ‘        \[oq]   u2018     single opening (left) quote
       ’        \[cq]   u2019     single closing (right) quote
       '        \[aq]   u0027     apostrophe, neutral single quote
       "        "       u0022     neutral double quote
       "        \[dq]   u0022     neutral double quote
       «        \[Fo]   u00AB     left double chevron
       »        \[Fc]   u00BB     right double chevron
       ‹        \[fo]   u2039     left single chevron
       ›        \[fc]   u203A     right single chevron

   [1mPunctuation[0m
       The  Unicode  name  for  U+00B7 is “middle dot”, which is unfortunately
       confusable with the [4mgroff[24m mnemonic for the visually similar but  seman‐
       tically  distinct multiplication dot; see subsection “Mathematical sym‐
       bols” below.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       ¡        \[r!]   u00A1     inverted exclamation mark
       ¿        \[r?]   u00BF     inverted question mark
       ·        \[pc]   u00B7     centered period
       —        \[em]   u2014     em‐dash +
       –        \[en]   u2013     en‐dash
       ‐        \[hy]   u2010     hyphen +

   [1mBrackets[0m
       On typesetting  devices,  the  bracket  extensions  are  font‐invariant
       glyphs;  that  is,  they  are  rendered the same way regardless of font
       (with a drawing escape sequence).  On terminals, they are [4mnot[24m  font‐in‐
       variant;  [4mgroff[24m  maps them rather arbitrarily to U+23AA (“curly bracket
       extension”).  In AT&T [4mtroff[24m, only one glyph was available to vertically
       extend brackets, braces, and parentheses: [1m\(bv[22m.

       Not all devices supply bracket pieces that can be piled up with [1m\b  [22mdue
       to  the restrictions of the escape’s piling algorithm.  A general solu‐
       tion to build brackets out of pieces is the following macro:
              .\" Make a pile centered vertically 0.5em above the baseline.
              .\" The first argument is placed at the top.
              .\" The pile is returned in string 'pile'.
              .eo
              .de pile-make
              .  nr pile-wd 0
              .  nr pile-ht 0
              .  ds pile-args
              .
              .  nr pile-# \n[.$]
              .  while \n[pile-#] \{\
              .    nr pile-wd (\n[pile-wd] >? \w'\$[\n[pile-#]]')
              .    nr pile-ht +(\n[rst] - \n[rsb])
              .    as pile-args \v'\n[rsb]u'\"
              .    as pile-args \Z'\$[\n[pile-#]]'\"
              .    as pile-args \v'-\n[rst]u'\"
              .    nr pile-# -1
              .  \}
              .
              .  ds pile \v'(-0.5m + (\n[pile-ht]u / 2u))'\"
              .  as pile \*[pile-args]\"
              .  as pile \v'((\n[pile-ht]u / 2u) + 0.5m)'\"
              .  as pile \h'\n[pile-wd]u'\"
              ..
              .ec

       Another complication is the  fact  that  some  glyphs  which  represent
       bracket pieces in AT&T [4mtroff[24m can be used for other mathematical symbols
       as  well,  for example [1m\(lf [22mand [1m\(rf[22m, which provide the floor operator.
       Some output devices, such as [1mdvi[22m, don’t unify such  glyphs.   For  this
       reason,  the glyphs [1m\[lf][22m, [1m\[rf][22m, [1m\[lc][22m, and [1m\[rc] [22mare not unified with
       similar‐looking bracket pieces.  In [4mgroff[24m, only glyphs with long  names
       are  guaranteed  to  pile  up  correctly for all devices—provided those
       glyphs are available.

       Output   Input               Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       [        [                   u005B     left square bracket
       [        \[lB]               u005B     left square bracket
       ]        ]                   u005D     right square bracket
       ]        \[rB]               u005D     right square bracket
       {        {                   u007B     left brace
       {        \[lC]               u007B     left brace
       }        }                   u007D     right brace
       }        \[rC]               u007D     right brace
       ⟨        \[la]               u27E8     left angle bracket
       ⟩        \[ra]               u27E9     right angle bracket
       ⎪        \[bv]               u23AA     brace vertical extension + ***
       ⎪        \[braceex]          u23AA     brace vertical extension

       ⎡        \[bracketlefttp]    u23A1     left square bracket top
       ⎢        \[bracketleftex]    u23A2     left square bracket extension
       ⎣        \[bracketleftbt]    u23A3     left square bracket bottom

       ⎤        \[bracketrighttp]   u23A4     right square bracket top
       ⎥        \[bracketrightex]   u23A5     right square bracket extension
       ⎦        \[bracketrightbt]   u23A6     right square bracket bottom

       ⎧        \[lt]               u23A7     left brace top +
       ⎨        \[lk]               u23A8     left brace middle +
       ⎩        \[lb]               u23A9     left brace bottom +
       ⎧        \[bracelefttp]      u23A7     left brace top
       ⎨        \[braceleftmid]     u23A8     left brace middle
       ⎩        \[braceleftbt]      u23A9     left brace bottom
       ⎪        \[braceleftex]      u23AA     left brace extension

       ⎫        \[rt]               u23AB     right brace top +
       ⎬        \[rk]               u23AC     right brace middle +
       ⎭        \[rb]               u23AD     right brace bottom +
       ⎫        \[bracerighttp]     u23AB     right brace top
       ⎬        \[bracerightmid]    u23AC     right brace middle
       ⎭        \[bracerightbt]     u23AD     right brace bottom
       ⎪        \[bracerightex]     u23AA     right brace extension

       ⎛        \[parenlefttp]      u239B     left parenthesis top
       ⎜        \[parenleftex]      u239C     left parenthesis extension
       ⎝        \[parenleftbt]      u239D     left parenthesis bottom
       ⎞        \[parenrighttp]     u239E     right parenthesis top
       ⎟        \[parenrightex]     u239F     right parenthesis extension
       ⎠        \[parenrightbt]     u23A0     right parenthesis bottom

   [1mArrows[0m
       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       ←        \[<-]   u2190     horizontal arrow left +
       →        \[->]   u2192     horizontal arrow right +
       ↔        \[<>]   u2194     bidirectional horizontal arrow
       ↓        \[da]   u2193     vertical arrow down +
       ↑        \[ua]   u2191     vertical arrow up +
       ↕        \[va]   u2195     bidirectional vertical arrow
       ⇐        \[lA]   u21D0     horizontal double arrow left
       ⇒        \[rA]   u21D2     horizontal double arrow right
       ⇔        \[hA]   u21D4     bidirectional horizontal double arrow
       ⇓        \[dA]   u21D3     vertical double arrow down
       ⇑        \[uA]   u21D1     vertical double arrow up
       ⇕        \[vA]   u21D5     bidirectional vertical double arrow
       ⎯        \[an]   u23AF     horizontal arrow extension

   [1mRules and lines[0m
       On typesetting  devices,  the  font‐invariant  glyphs  (see  subsection
       “Brackets”  above)  [1m\[br][22m, [1m\[ul][22m, and [1m\[rn] [22mform corners when adjacent;
       they can be used to build boxes.  On terminal devices, they are  mapped
       as shown in the table.  The Unicode‐derived names of these three glyphs
       are approximations.

       The  input  character [1m_ [22malways accesses the underscore glyph in a font;
       [1m\[ul][22m, by contrast, may be font‐invariant on typesetting devices.

       The baseline rule [1m\[ru] [22mis a font‐invariant glyph,  namely  a  rule  of
       one‐half em.

       In  AT&T  [4mtroff[24m,  [1m\[rn] [22malso served as a one en extension of the square
       root symbol.  [4mgroff[24m favors [1m\[radicalex] [22mfor this purpose;  see  subsec‐
       tion “Mathematical symbols” below.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       |        |       u007C     bar
       |        \[ba]   u007C     bar
       │        \[br]   u2502     box rule +
       _        _       u005F     underscore, low line +
       _        \[ul]   ‐‐‐       underrule +
       ‾        \[rn]   u203E     overline +
       _        \[ru]   ‐‐‐       baseline rule +
       ¦        \[bb]   u00A6     broken bar
       /        /       u002F     slash, solidus +
       /        \[sl]   u002F     slash, solidus +
       \        \[rs]   u005C     reverse solidus

   [1mText markers[0m
       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       ○        \[ci]   u25CB     circle +
       •        \[bu]   u2022     bullet +
       †        \[dg]   u2020     dagger +
       ‡        \[dd]   u2021     double dagger +
       ◊        \[lz]   u25CA     lozenge, diamond
       □        \[sq]   u25A1     square +
       ¶        \[ps]   u00B6     pilcrow sign
       §        \[sc]   u00A7     section sign +
       ☜        \[lh]   u261C     hand pointing left +
       ☞        \[rh]   u261E     hand pointing right +
       @        @       u0040     at sign
       @        \[at]   u0040     at sign
       #        #       u0023     number sign
       #        \[sh]   u0023     number sign
       ↵        \[CR]   u21B5     carriage return
       ✓        \[OK]   u2713     check mark

   [1mLegal symbols[0m
       The Bell System logo is not supported in [4mgroff[24m.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       ©        \[co]   u00A9     copyright sign +
       ®        \[rg]   u00AE     registered sign +
       ™        \[tm]   u2122     trade mark sign
                \[bs]   ‐‐‐       Bell System logo +

   [1mCurrency symbols[0m
       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       $        $       u0024     dollar sign
       $        \[Do]   u0024     dollar sign
       ¢        \[ct]   u00A2     cent sign +
       €        \[eu]   u20AC     Euro sign
       €        \[Eu]   u20AC     variant Euro sign
       ¥        \[Ye]   u00A5     yen sign
       £        \[Po]   u00A3     pound sign
       ¤        \[Cs]   u00A4     currency sign

   [1mUnits[0m
       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       °        \[de]   u00B0     degree sign +
       ‰        \[%0]   u2030     per thousand, per mille sign
       ′        \[fm]   u2032     arc minute sign, foot mark +
       ″        \[sd]   u2033     arc second sign
       µ        \[mc]   u00B5     micro sign
       ª        \[Of]   u00AA     feminine ordinal indicator
       º        \[Om]   u00BA     masculine ordinal indicator

   [1mLogical symbols[0m
       The  variants  of  the not sign may differ in appearance or spacing de‐
       pending on the device and font selected.  Unicode  does  not  encode  a
       discrete “bitwise or” sign: on typesetting devices, it is drawn shorter
       than  the bar, about the same height as a capital letter.  Terminal de‐
       vices unify [1m\[ba] [22mand [1m\[or][22m.

       Output   Input    Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       ∧        \[AN]    u2227     logical and
       ∨        \[OR]    u2228     logical or
       ¬        \[no]    u00AC     logical not + ***
       ¬        \[tno]   u00AC     text variant of [1m\[no][0m
       ∃        \[te]    u2203     there exists
       ∀        \[fa]    u2200     for all
       ∋        \[st]    u220B     such that
       ∴        \[3d]    u2234     therefore
       ∴        \[tf]    u2234     therefore
       |        |        u007C     bar
       |        \[or]    u007C     bitwise or +

   [1mMathematical symbols[0m
       [1m\[Fn] [22malso appears in subsection “Supplementary Latin  letters”  above.
       Observe  the two varieties of the plus‐minus, multiplication, and divi‐
       sion signs; [1m\[+-][22m, [1m\[mu][22m, and [1m\[di] [22mare normally drawn from the special
       font, but have text font variants.   Also  be  aware  of  three  glyphs
       available  in  special  font variants that are normally drawn from text
       fonts: the plus, minus, and equals signs.  These variants may differ in
       appearance or spacing depending on the device and font selected.

       In AT&T [4mtroff[24m, [1m\(rn [22m(“root en extender”) served as the  horizontal  ex‐
       tension  of  the radical (square root) sign, [1m\(sr[22m, and was drawn at the
       maximum height of the typeface’s bounding box; this enabled the special
       character to double as an overline (see subsection  “Rules  and  lines”
       above).  A contemporary font’s radical sign might not ascend to such an
       extreme.   In  [4mgroff[24m,  you can instead use [1m\[radicalex] [22mto continue the
       radical sign [1m\[sr][22m; these special characters are intended for use  with
       text  fonts.   [1m\[sqrt] [22mand [1m\[sqrtex] [22mare their counterparts with mathe‐
       matical spacing.

       Output   Input          Unicode      Notes
       ────────────────────────────────────────────────────────────────────────
       ½        \[12]          u00BD        one half symbol +
       ¼        \[14]          u00BC        one quarter symbol +
       ¾        \[34]          u00BE        three quarters symbol +
       ⅛        \[18]          u215B        one eighth symbol
       ⅜        \[38]          u215C        three eighths symbol
       ⅝        \[58]          u215D        five eighths symbol
       ⅞        \[78]          u215E        seven eighths symbol
       ¹        \[S1]          u00B9        superscript one
       ²        \[S2]          u00B2        superscript two
       ³        \[S3]          u00B3        superscript three

       +        +              u002B        plus
       +        \[pl]          u002B        special variant of plus + ***
       -        \[-]           u002D        minus
       −        \[mi]          u2212        special variant of minus + ***
       ∓        \[-+]          u2213        minus‐plus
       ±        \[+-]          u00B1        plus‐minus + ***
       ±        \[t+-]         u00B1        text variant of [1m\[+-][0m
       ⋅        \[md]          u22C5        multiplication dot
       ×        \[mu]          u00D7        multiplication sign + ***
       ×        \[tmu]         u00D7        text variant of [1m\[mu][0m
       ⊗        \[c*]          u2297        circled times
       ⊕        \[c+]          u2295        circled plus
       ÷        \[di]          u00F7        division sign + ***
       ÷        \[tdi]         u00F7        text variant of [1m\[di][0m
       ⁄        \[f/]          u2044        fraction slash
       *        *              u002A        asterisk
       ∗        \[**]          u2217        mathematical asterisk +

       ≤        \[<=]          u2264        less than or equal to +
       ≥        \[>=]          u2265        greater than or equal to +
       ≪        \[<<]          u226A        much less than
       ≫        \[>>]          u226B        much greater than
       =        =              u003D        equals
       =        \[eq]          u003D        special variant of equals + ***
       ≠        \[!=]          u003D_0338   not equals +
       ≡        \[==]          u2261        equivalent +
       ≢        \[ne]          u2261_0338   not equivalent
       ≅        \[=~]          u2245        approximately equal to
       ≃        \[|=]          u2243        asymptotically equal to +
       ~        \[ti]          u007E        tilde +
       ∼        \[ap]          u223C        similar to, tilde operator +
       ≈        \[~~]          u2248        almost equal to
       ≈        \[~=]          u2248        almost equal to
       ∝        \[pt]          u221D        proportional to +

       ∅        \[es]          u2205        empty set +
       ∈        \[mo]          u2208        element of a set +
       ∉        \[nm]          u2208_0338   not element of set
       ⊂        \[sb]          u2282        proper subset +
       ⊄        \[nb]          u2282_0338   not subset
       ⊃        \[sp]          u2283        proper superset +
       ⊅        \[nc]          u2283_0338   not superset
       ⊆        \[ib]          u2286        subset or equal +
       ⊇        \[ip]          u2287        superset or equal +
       ∩        \[ca]          u2229        intersection, cap +
       ∪        \[cu]          u222A        union, cup +

       ∠        \[/_]          u2220        angle
       ⊥        \[pp]          u22A5        perpendicular
       ∫        \[is]          u222B        integral +
       ∫        \[integral]    u222B        integral ***
       ∑        \[sum]         u2211        summation ***
       ∏        \[product]     u220F        product ***
       ∐        \[coproduct]   u2210        coproduct ***
       ∇        \[gr]          u2207        gradient +
       √        \[sr]          u221A        radical sign, square root +
       ‾        \[rn]          u203E        overline +
       ‾        \[radicalex]   ‐‐‐          radical extension
       √        \[sqrt]        u221A        radical sign, square root ***
       ‾        \[sqrtex]      ‐‐‐          radical extension ***

       ⌈        \[lc]          u2308        left ceiling +
       ⌉        \[rc]          u2309        right ceiling +
       ⌊        \[lf]          u230A        left floor +
       ⌋        \[rf]          u230B        right floor +

       ∞        \[if]          u221E        infinity +
       ℵ        \[Ah]          u2135        aleph symbol
       ƒ        \[Fn]          u0192        lowercase f with hook, function
       ℑ        \[Im]          u2111        blackletter I, imaginary part
       ℜ        \[Re]          u211C        blackletter R, real part
       ℘        \[wp]          u2118        Weierstrass p
       ∂        \[pd]          u2202        partial differential
       ℏ        \[-h]          u210F        h bar
       ℏ        \[hbar]        u210F        h bar

   [1mGreek glyphs[0m
       These glyphs are intended for technical use, not for typesetting  Greek
       language  text; normally, the uppercase letters have upright shape, and
       the lowercase ones are slanted.

       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       Α        \[*A]   u0391     uppercase alpha +
       Β        \[*B]   u0392     uppercase beta +
       Γ        \[*G]   u0393     uppercase gamma +
       Δ        \[*D]   u0394     uppercase delta +
       Ε        \[*E]   u0395     uppercase epsilon +
       Ζ        \[*Z]   u0396     uppercase zeta +
       Η        \[*Y]   u0397     uppercase eta +
       Θ        \[*H]   u0398     uppercase theta +
       Ι        \[*I]   u0399     uppercase iota +
       Κ        \[*K]   u039A     uppercase kappa +
       Λ        \[*L]   u039B     uppercase lambda +
       Μ        \[*M]   u039C     uppercase mu +
       Ν        \[*N]   u039D     uppercase nu +
       Ξ        \[*C]   u039E     uppercase xi +
       Ο        \[*O]   u039F     uppercase omicron +
       Π        \[*P]   u03A0     uppercase pi +
       Ρ        \[*R]   u03A1     uppercase rho +
       Σ        \[*S]   u03A3     uppercase sigma +
       Τ        \[*T]   u03A4     uppercase tau +
       Υ        \[*U]   u03A5     uppercase upsilon +
       Φ        \[*F]   u03A6     uppercase phi +
       Χ        \[*X]   u03A7     uppercase chi +
       Ψ        \[*Q]   u03A8     uppercase psi +
       Ω        \[*W]   u03A9     uppercase omega +

       α        \[*a]   u03B1     lowercase alpha +
       β        \[*b]   u03B2     lowercase beta +
       γ        \[*g]   u03B3     lowercase gamma +
       δ        \[*d]   u03B4     lowercase delta +
       ε        \[*e]   u03B5     lowercase epsilon +
       ζ        \[*z]   u03B6     lowercase zeta +
       η        \[*y]   u03B7     lowercase eta +
       θ        \[*h]   u03B8     lowercase theta +
       ι        \[*i]   u03B9     lowercase iota +
       κ        \[*k]   u03BA     lowercase kappa +
       λ        \[*l]   u03BB     lowercase lambda +
       μ        \[*m]   u03BC     lowercase mu +
       ν        \[*n]   u03BD     lowercase nu +
       ξ        \[*c]   u03BE     lowercase xi +
       ο        \[*o]   u03BF     lowercase omicron +
       π        \[*p]   u03C0     lowercase pi +
       ρ        \[*r]   u03C1     lowercase rho +
       σ        \[*s]   u03C3     lowercase sigma +
       τ        \[*t]   u03C4     lowercase tau +
       υ        \[*u]   u03C5     lowercase upsilon +
       ϕ        \[*f]   u03D5     lowercase phi +
       χ        \[*x]   u03C7     lowercase chi +
       ψ        \[*q]   u03C8     lowercase psi +
       ω        \[*w]   u03C9     lowercase omega +

       ϵ        \[+e]   u03F5     variant epsilon (lunate)
       ϑ        \[+h]   u03D1     variant theta (cursive form)
       ϖ        \[+p]   u03D6     variant pi (similar to omega)
       φ        \[+f]   u03C6     variant phi (curly shape)
       ς        \[ts]   u03C2     terminal lowercase sigma +

   [1mPlaying card symbols[0m
       Output   Input   Unicode   Notes
       ────────────────────────────────────────────────────────────────────────
       ♣        \[CL]   u2663     solid club suit
       ♠        \[SP]   u2660     solid spade suit
       ♥        \[HE]   u2665     solid heart suit
       ♦        \[DI]   u2666     solid diamond suit

[1mHistory[0m
       A consideration of the typefaces originally available to AT&T [4mnroff[24m and
       [4mtroff[24m illuminates many conventions that one might  regard  as  idiosyn‐
       cratic  fifty  years  afterward.  (See section “History” of [4mroff[24m(7) for
       more context.)  The face used by the Teletype Model 37 terminals of the
       Murray Hill Unix Room was based on ASCII, but assigned  multiple  mean‐
       ings to several code points, as suggested by that standard.  Decimal 34
       ([1m"[22m) served as a dieresis accent and neutral double quotation mark; dec‐
       imal  39 ([1m'[22m) as an acute accent, apostrophe, and closing (right) single
       quotation mark; decimal 45 ([1m-[22m) as a hyphen and a minus sign; decimal 94
       ([1m^[22m) as a circumflex accent and caret; decimal 96 ([1m`[22m) as a grave  accent
       and  opening  (left)  single  quotation  mark; and decimal 126 ([1m~[22m) as a
       tilde accent and (with a half‐line motion) swung dash.   The  Model  37
       bore  an optional extended character set offering upright Greek letters
       and several mathematical symbols; these were documented as early as the
       [4mkbd[24m(VII) man page of the (First Edition) [4mUnix[24m [4mProgrammer’s[24m [4mManual.[0m

       At the time Graphic Systems  delivered  the  C/A/T  phototypesetter  to
       AT&T, the ASCII character set was not considered a standard basis for a
       glyph  repertoire  by traditional typographers.  In the stock Times ro‐
       man, italic, and bold styles available, several ASCII  characters  were
       not  present  at all, nor was most of the Teletype’s extended character
       set.  AT&T commissioned a “special” font to ensure no  loss  of  reper‐
       toire.

       A  representation  of  the  coverage of the C/A/T’s text fonts follows.
       The glyph resembling an underscore is a baseline rule, and that  resem‐
       bling  a vertical line is a box rule.  In italics, the box rule was not
       slanted.  We also observe that the hyphen and minus sign  were  already
       “de‐unified”  by the fonts provided; a decision whither to map an input
       “-” therefore had to be taken.

              ┌─────────────────────────────────────────────────────┐
              │ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z │
              │ a b c d e f g h i j k l m n o p q r s t u v w x y z │
              │ 0 1 2 3 4 5 6 7 8 9 fi fl ffi ffl                   │
              │ ! $ % & ( ) ‘ ’ * + - . , / : ; = ? [ ] │           │
              │ • □ — ‐ _ ¼ ½ ¾ ° † ′ ¢ ® ©                         │
              └─────────────────────────────────────────────────────┘

       The special font supplied  the  missing  ASCII  and  Teletype  extended
       glyphs,  among  several  others.  The plus, minus, and equals signs ap‐
       peared in the special font despite availability in text fonts “to insu‐
       late the appearance of equations from the  choice  of  standard  [read:
       text] fonts”—a priority since [4mtroff[24m was turned to the task of mathemat‐
       ical typesetting as soon as it was developed.

       We note that AT&T took the opportunity to de‐unify the apostrophe/right
       single  quotation mark from the acute accent (a choice ISO later dupli‐
       cated in its 8859 series of standards).  A slash intended to be mirror‐
       symmetric with the backslash was also included, as was the Bell  System
       logo; we do not attempt to depict the latter.

           ┌───────────────────────────────────────────────────────────┐
           │ [4mα[24m [4mβ[24m [4mγ[24m [4mδ[24m [4mε[24m [4mζ[24m [4mη[24m [4mθ[24m [4mι[24m [4mκ[24m [4mλ[24m [4mμ[24m [4mν[24m [4mξ[24m [4mο[24m [4mπ[24m [4mρ[24m [4mσ[24m [4mς[24m [4mτ[24m [4mυ[24m [4mϕ[24m [4mχ[24m [4mψ[24m [4mω[24m         │
           │ Γ Δ Θ Λ Ξ Π Σ Υ Φ Ψ Ω                                     │
           │ " ´ \ ^ _ ` ~ / < > { } # @ + − = ∗                       │
           │ ≥ ≤ ≡ ≈ ∼ ≠ ↑ ↓ ← → × ÷ ± ∞ ∂ ∇ ¬ ∫ ∝ √ ‾ ∪ ∩ ⊂ ⊃ ⊆ ⊇ ∅ ∈ │
           │ § ‡ ☜ ☞ | ○ ⎧ ⎩ ⎫ ⎭ ⎨ ⎬ ⎪ ⌊ ⌋ ⌈ ⌉                         │
           └───────────────────────────────────────────────────────────┘

       One  ASCII  character  as rendered by the Model 37 was apparently aban‐
       doned.  That device printed decimal 124 (|) as a broken vertical  line,
       like Unicode U+00A6 (¦).  No equivalent was available on the C/A/T; the
       box rule [1m\[br][22m, brace vertical extension [1m\[bv][22m, and “or” operator [1m\[or][0m
       were used as contextually appropriate.

       Devices  supported by AT&T device‐independent [4mtroff[24m exhibited some dif‐
       ferences in glyph detail.  For example, on the Autologic  APS‐5  photo‐
       typesetter, the square [1m\(sq [22mbecame filled in the Times bold face.

[1mFiles[0m
       The files below are loaded automatically by the default [4mtroffrc[24m.

       [4m/usr/share/groff/1.23.0/tmac/composite.tmac[0m
              assigns  alternate mappings for identifiers after the first in a
              composite special character  escape  sequence.   See  subsection
              “Accents” above.

       [4m/usr/share/groff/1.23.0/tmac/fallbacks.tmac[0m
              defines  fallback  mappings  for Unicode code points such as the
              increment sign (U+2206) and upper‐ and lowercase Roman numerals.

[1mAuthors[0m
       This document was written by James Clark ⟨jjc@jclark.com⟩,  with  addi‐
       tions  by  Werner  Lemberg  ⟨wl@gnu.org⟩  and Bernd Warken ⟨groff-bernd
       .warken-72@web.de⟩, revised to use [4mtbl[24m(1)  by  Eric  S.  Raymond  ⟨esr@
       thyrsus.com⟩,  and  largely rewritten by G. Branden Robinson ⟨g.branden
       .robinson@gmail.com⟩.

[1mSee also[0m
       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher  and  Werner
       Lemberg,  is  the primary [4mgroff[24m manual.  Section “Using Symbols” may be
       of particular  note.   You  can  browse  it  interactively  with  “info
       '(groff) Using Symbols'”.

       “An extension to the [4mtroff[24m character set for Europe”, E.G. Keizer, K.J.
       Simonsen, J. Akkerhuis; EUUG Newsletter, Volume 9, No. 2, Summer 1989

       The Unicode Standard ⟨http://www.unicode.org⟩

       “7‐bit  Character Sets” ⟨https://www.aivosto.com/articles/charsets-7bit
       .html⟩ by Tuomas Salste documents the inherent  ambiguity  and  config‐
       urable code points of the ASCII encoding standard.

       “Nroff/Troff User’s Manual” by Joseph F. Ossanna, 1976, AT&T Bell Labo‐
       ratories Computing Science Technical Report No. 54, features two tables
       that throw light on the glyph repertoire available to “typesetter [4mroff[24m”
       when  it  was first written.  Be careful of re‐typeset versions of this
       document that can be found on the Internet.   Some  do  not  accurately
       represent  the original document: several glyphs are obviously missing.
       More subtly, lowercase Greek letters are rendered upright, not  slanted
       as  they  appeared in the C/A/T’s special font and as expected by [4mtroff[0m
       users.

       [4mgroff_rfc1345[24m(7) describes an  alternative  set  of  special  character
       glyph  names, which extends and in some cases overrides the definitions
       listed above.

       [4mgroff[24m(1), [4mtroff[24m(1), [4mgroff[24m(7)

groff 1.23.0                      5 July 2023                    [4mgroff_char[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_diff[24m(7)          Miscellaneous Information Manual          [4mgroff_diff[24m(7)

[1mName[0m
       groff_diff - differences between GNU [4mroff[24m and AT&T [4mtroff[0m

[1mDescription[0m
       The GNU [4mroff[24m text processing system, [4mgroff[24m, is  an  extension  of  AT&T
       [4mtroff[24m, the typesetting system originating in Unix systems of the 1970s.
       [4mgroff[24m removes many arbitrary limitations and adds features, both to the
       input language and to the page description language output by the [4mtroff[0m
       formatter.   Differences  arising  from  [4mgroff[24m’s implementation of AT&T
       [4mtroff[24m features are also noted.  See [4mroff[24m(7) for background.

[1mLanguage[0m
       GNU [4mtroff[24m features identifiers of arbitrary length; supports color out‐
       put, non‐integral type sizes, and user‐defined  characters;  adds  more
       conditional  expression  operators; recognizes additional scaling units
       and numeric operators; enables  general  file  I/O  (in  “unsafe  mode”
       only); and exposes more formatter state.

   [1mLong names[0m
       GNU  [4mtroff[24m introduces many new requests; with three exceptions ([1mcp[22m, [1mdo[22m,
       [1mrj[22m), they have names longer than two characters.  The names  of  regis‐
       ters,  fonts,  strings/macros/diversions, environments, special charac‐
       ters, streams, and colors can be of any length.   Anywhere  AT&T  [4mtroff[0m
       supports a parameterized escape sequence that uses an opening parenthe‐
       sis “(” to introduce a two‐character argument, [4mgroff[24m supports a square‐
       bracketed  form  “[]”  where  the  argument  within can be of arbitrary
       length.

   [1mFont families, abstract styles, and translation[0m
       GNU [4mtroff[24m can group text typefaces into [4mfamilies[24m containing each of the
       styles “[1mR[22m”, “[1mI[22m”, “[1mB[22m”, and “[1mBI[22m”.  So that a document need not be coupled
       to a specific font family, an output device can associate  a  style  in
       the  abstract  sense with a mounting position.  Thus the default family
       can be combined with a style dynamically,  producing  a  [4mresolved[24m  [4mfont[0m
       [4mname.[24m  A document can [4mtranslate,[24m or remap, fonts with the [1mftr [22mrequest.

       Applying the requests [1mcs[22m, [1mbd[22m, [1mtkf[22m, [1muf[22m, or [1mfspecial [22mto an abstract style
       affects  the  member of the default family corresponding to that style.
       The default family can be set with the [1mfam [22mrequest or  [1m-f  [22mcommand‐line
       option.  The [1mstyles [22mdirective in the output device’s [4mDESC[24m file controls
       which  mounting  positions  (if  any) are initially associated with ab‐
       stract styles rather than fonts, and the [1msty [22mrequest  can  update  this
       association.

   [1mColors[0m
       [4mgroff[24m supports color output with a variety of color spaces and up to 16
       bits  per  channel.   Some devices, particularly terminals, may be more
       limited.  When color support is enabled, two colors are current at  any
       given  time:  the  [4mstroke[24m  [4mcolor,[24m with which glyphs, rules (lines), and
       geometric figures are drawn, and the [4mfill[24m [4mcolor,[24m which paints the inte‐
       rior of filled geometric figures.  The  [1mcolor[22m,  [1mdefcolor[22m,  [1mgcolor[22m,  and
       [1mfcolor  [22mrequests;  [1m\m  [22mand  [1m\M [22mescape sequences; and [1m.color[22m, [1m.m[22m, and [1m.M[0m
       registers exercise color support.

   [1mFractional type sizes and new scaling units[0m
       AT&T [4mtroff[24m interpreted all type size measurements in points.   Combined
       with  integer arithmetic, this design choice made it impossible to sup‐
       port, for instance, ten and a half‐point type.  In GNU [4mtroff[24m, an output
       device can select a scaling factor that subdivides a point into “scaled
       points”.  A type size expressed in scaled points can thus  represent  a
       non‐integral type size.

       A [4mscaled[24m [4mpoint[24m is equal to 1/[4msizescale[24m points, where [4msizescale[24m is spec‐
       ified  in  the  device  description  file, [4mDESC[24m, and defaults to 1; see
       [4mgroff_font[24m(5).  Requests and escape sequences in  GNU  [4mtroff[24m  interpret
       arguments  that  represent  a  type size in points, which the formatter
       multiplies by [4msizescale[24m and converts to an integer.  Arguments  treated
       in  this  way  comprise those to the escape sequences [1m\H [22mand [1m\s[22m, to the
       request [1mps[22m, the third argument to the [1mcs [22mrequest, and  the  second  and
       fourth  arguments  to  the [1mtkf [22mrequest.  Scaled points may be specified
       explicitly with the [1mz [22mscaling unit.  In GNU [4mtroff[24m, the register  [1m\n[.s][0m
       can  interpolate a non‐integral type size.  The register [1m\n[.ps] [22minter‐
       polates the type size in scaled points.

       For example, if [4msizescale[24m is 1000, then a scaled  point  is  one  thou‐
       sandth  of  a  point.  Consequently, “[1m.ps 10.5[22m” is synonymous with “[1m.ps[0m
       [1m10.5z[22m”; both set the type size to 10,500 scaled points, or 10.5 points.

       It makes no sense to use the “[1mz[22m” scaling unit in a  numeric  expression
       whose  default scaling unit is neither “[1mu[22m” nor “[1mz[22m”, so GNU [4mtroff[24m disal‐
       lows this.  Similarly, it is nonsensical to use a  scaling  unit  other
       than  “[1mz[22m”  or  “[1mu[22m”  in  a numeric expression whose default scaling unit
       is “[1mz[22m”, so GNU [4mtroff[24m disallows this as well.

       Another new scaling unit, “[1ms[22m”, multiplies by the number of basic  units
       in  a  scaled  point.  Thus, “[1m\n[.ps]s[22m” is equal to “[1m1m[22m” by definition.
       Do not confuse the “[1ms[22m” and “[1mz[22m” scaling units.

       Output devices may be limited in the type sizes they can  employ.   The
       [1m.s  [22mand [1m.ps [22mregisters represent the type size as selected by the output
       driver as it understands a device’s  capability.   The  last  [4mrequested[0m
       type  size  is  interpolated in scaled points by the read‐only register
       [1m.psr [22mand in points as a decimal fraction by the read‐only string‐valued
       register [1m.sr[22m.  Both are associated with the environment.  For  example,
       if  a type size of 10.95 points is requested, and the nearest size per‐
       mitted by a [1msizes [22mrequest (or by the [1msizes [22mor [1msizescale  [22mdirectives  in
       the device’s [4mDESC[24m file) is 11 points, the output driver uses the latter
       value.

       A  further  two new measurement units available in [4mgroff[24m are “[1mM[22m”, which
       indicates hundredths of an em, and “[1mf[22m”,  which  multiplies  by  65,536.
       The latter provides convenient fractions for color definitions with the
       [1mdefcolor [22mrequest.  For example, 0.5f equals 32768u.

   [1mNumeric expressions[0m
       GNU  [4mtroff[24m  permits  spaces in a numeric expression within parentheses,
       and offers three new operators.

       [4me1[24m[1m>?[4m[22me2[24m Interpolate the greater of [4me1[24m and [4me2[24m.

       [4me1[24m[1m<?[4m[22me2[24m Interpolate the lesser of [4me1[24m and [4me2[24m.

       [1m([4m[22mc[24m[1m;[4m[22me[24m[1m)  [22mEvaluate [4me[24m using [4mc[24m as the default scaling unit, ignoring scaling
              units in [4me[24m if [4mc[24m is empty.

   [1mConditional expressions[0m
       More conditions can be tested with the “[1mif[22m” and [1mie [22mrequests, as well as
       the new “[1mwhile[22m” request.

       [1mc [4m[22mchr[24m  True if a character [4mchr[24m is available, where [4mchr[24m is  an  ordinary
              character  (Unicode basic Latin excluding control characters and
              the space), a special character, or [1m\N'[4m[22mindex[24m[1m'[22m.

       [1md [4m[22mnam[24m  True if a string, macro, diversion, or request [4mnam[24m is defined.

       [1mF [4m[22mfnt[24m  True if a font [4mfnt[24m is available; [4mfnt[24m can be an abstract style or
              a font name.  [4mfnt[24m is handled as if it were accessed with the  [1mft[0m
              request  (that  is, abstract styles and font translation are ap‐
              plied), but [4mfnt[24m cannot be a mounting position, and  no  font  is
              mounted.

       [1mm [4m[22mcol[24m  True if a color [4mcol[24m is defined.

       [1mr [4m[22mreg[24m  True if a register [4mreg[24m is defined.

       [1mS [4m[22msty[24m  True if a style [4msty[24m is registered.  Font translation applies.

       [1mv      [22mAlways  false.  This condition is for compatibility with certain
              other [4mtroff[24m implementations only.  (This  refers  to  [4mvtroff[24m,  a
              translator  that  would convert the C/A/T output from early‐vin‐
              tage AT&T [4mtroff[24m to a form suitable for Versatec and  Benson‐Var‐
              ian plotters.)

   [1mDrawing commands[0m
       GNU  [4mtroff[24m  offers  drawing  commands  to create filled circles and el‐
       lipses, and polygons.  Stroked (outlined) objects are  drawn  with  the
       stroke color and filled (solid) ones shaded with the fill color.  These
       are  independent  properties; if you want a filled, stroked figure, you
       must draw the same figure twice using each drawing command.   A  filled
       figure is always smaller than a stroked one because the former is drawn
       only  within  its  defined  area, whereas strokes have a line thickness
       (set with another new drawing command, [1m\D't'[22m).

   [1mEscape sequences[0m
       [4mgroff[24m introduces several new escape sequences and extends the syntax of
       a few AT&T [4mtroff[24m escape sequences (namely, [1m\D[22m, [1m\f[22m, [1m\k[22m, [1m\n[22m, [1m\s[22m, [1m\$[22m,  and
       [1m\*[22m).   In  the following list, escape sequences are collated alphabeti‐
       cally at first, and then by symbol roughly in Unicode code point order.

       [1m\A'[4m[22manything[24m[1m'[0m
              Interpolate 1 if [4manything[24m is a valid identifier,  and  0  other‐
              wise.   Because  invalid  input  characters are removed, invalid
              identifiers are empty or contain spaces, tabs, or newlines.  You
              can employ [1m\A [22mto validate a macro argument before  using  it  to
              construct another escape sequence or identifier.

       [1m\B'[4m[22manything[24m[1m'[0m
              Interpolate  1  if [4manything[24m is a valid numeric expression, and 0
              otherwise.  You might use [1m\B [22malong with the “[1mif[22m” request to fil‐
              ter out invalid macro arguments.

       [1m\D'C [4m[22md[24m[1m'[0m
              Draw filled circle of diameter [4md[24m with its leftmost point at  the
              drawing position.

       [1m\D'E [4m[22mh[24m [4mv[24m[1m'[0m
              Draw  filled  ellipse  with [4mh[24m and [4mv[24m as the axes and the leftmost
              point at the drawing position.

       [1m\D'p [4m[22mh1[24m [4mv1[24m ... [4mhn[24m [4mvn[24m[1m'[0m
              Draw polygon with vertices at drawing position and each point in
              sequence.  GNU [4mtroff[24m closes the polygon by drawing a  line  from
              ([4mhn[24m,  [4mvn[24m) back to the initial drawing position; DWB and Heirloom
              [4mtroff[24ms do not.  Afterward,  the  drawing  position  is  left  at
              ([4mhn[24m, [4mvn[24m).

       [1m\D'P [4m[22mh1[24m [4mv1[24m ... [4mhn[24m [4mvn[24m[1m'[0m
              As [1m\D'p'[22m, but the polygon is filled.

       [1m\D't [4m[22mn[24m[1m'[0m
              Set  line thickness of geometric objects to to [4mn[24m basic units.  A
              zero [4mn[24m selects the minimal supported thickness.   A  negative  [4mn[0m
              selects  a  thickness proportional to the type size; this is the
              default.

       [1m\E     [22mEmbed an escape character that is not interpreted in  copy  mode
              (compare with [1m\a [22mand [1m\t[22m).  You can use it to ease the writing of
              nested  macro  definitions.   It  is  also  convenient to define
              strings containing escape sequences that need to work when  used
              in copy mode (for example, as macro arguments), or which will be
              interpolated at varying macro nesting depths.

       [1m\f[[4m[22mfont[24m[1m][0m
              Select  [4mfont[24m,  which may be a mounting position, abstract style,
              or font name, to choose the typeface.  [1m\f[]  [22mand  [1m\fP  [22mare  syn‐
              onyms; we recommend the former.

       [1m\F[4m[22mf[0m
       [1m\F([4m[22mfm[0m
       [1m\F[[4m[22mfamily[24m[1m][0m
              Select default font family.  [1m\F[] [22mmakes the previous font family
              the  default.   [1m\FP [22mis unlike [1m\fP[22m; it selects font family “P” as
              the default.  See the [1mfam [22mrequest below.

       [1m\k([4m[22mrg[0m
       [1m\k[[4m[22mreg[24m[1m][0m
              Mark  horizontal  drawing  position  in  two‐character  register
              name [4mrg[24m or arbitrary register name [4mreg[24m.

       [1m\m[4m[22mc[0m
       [1m\m([4m[22mcl[0m
       [1m\m[[4m[22mcol[24m[1m][0m
              Set  the stroke color.  [1m\m[] [22mrestores the previous stroke color,
              or the default if there is none.

       [1m\M[4m[22mc[0m
       [1m\M([4m[22mcl[0m
       [1m\M[[4m[22mcol[24m[1m][0m
              Set the fill color.  [1m\M[] [22mrestores the previous fill  color,  or
              the default if there is none.

       [1m\n[[4m[22mreg[24m[1m][0m
              Interpolate register [4mreg[24m.

       [1m\O[4m[22mn[0m
       [1m\O[[4m[22mn[24m[1m]  [22mSuppress  [4mtroff[24m output of glyphs and geometric objects.  The se‐
              quences [1m\O2[22m, [1m\O3[22m, [1m\O4[22m, and [1m\O5 [22mare intended for internal use  by
              [4mgrohtml[24m(1).

              [1m\O0[0m
              [1m\O1    [22mDisable  and enable, respectively, the emission of glyphs
                     and geometric objects to the output driver, provided that
                     this sequence occurs at the outermost  suppression  level
                     (see  [1m\O3  [22mand [1m\O4[22m).  Horizontal motions corresponding to
                     non‐overstruck glyph widths still occur.  These sequences
                     also reset the registers [1mopminx[22m, [1mopminy[22m, [1mopmaxx[22m, and  [1mop‐[0m
                     [1mmaxy  [22mto  -1.  These four registers mark the top left and
                     bottom right hand corners of a box encompassing all writ‐
                     ten or drawn output.

              [1m\O2    [22mAt the outermost suppression level,  enable  emission  of
                     glyphs  and  geometric objects, and write to the standard
                     error stream the page  number  and  values  of  the  four
                     aforementioned   registers  encompassing  glyphs  written
                     since the last interpolation of a [1m\O [22msequence, as well as
                     the page offset, line length, image file name  (if  any),
                     horizontal  and  vertical device motion quanta, and input
                     file name.  Numeric values are in basic units.

              [1m\O3[0m
              [1m\O4    [22mBegin and end a nested suppression  level,  respectively.
                     [4mgrohtml[24m  uses  this  mechanism to create images of output
                     preprocessed with [4mpic[24m, [4meqn[24m, and [4mtbl[24m.  At  startup,  [4mtroff[0m
                     is  at the outermost suppression level.  [4mpre-grohtml[24m gen‐
                     erates these sequences when processing the document,  us‐
                     ing [4mtroff[24m with the [1mps [22moutput device, Ghostscript, and the
                     PNM  tools  to  produce  images in PNG format.  These se‐
                     quences start a new page if the device  is  not  [1mhtml  [22mor
                     [1mxhtml[22m,  to  reduce  the  number of images crossing a page
                     boundary.

              [1m\O5[[4m[22mPfile[24m[1m][0m
                     At the outermost suppression level, write the  name  [4mfile[0m
                     to the standard error stream at position [4mP[24m, which must be
                     one  of [1ml[22m, [1mr[22m, [1mc[22m, or [1mi[22m, corresponding to left, right, cen‐
                     tered, and inline alignments within the document, respec‐
                     tively.  [4mfile[24m is is a name associated with the production
                     of the next image.

       [1m\R'[4m[22mname[24m [4m±n[24m[1m'[0m
              Synonymous with “[1m.nr [4m[22mname[24m [4m±n[24m”.

       [1m\s[[4m[22m±n[24m[1m][0m
       [1m\s[4m[22m±[24m[1m[[4m[22mn[24m[1m][0m
       [1m\s'[4m[22m±n[24m[1m'[0m
       [1m\s[4m[22m±[24m[1m'[4m[22mn[24m[1m' [22mSet the type size to, or increment or decrement it by, [4mn[24m  scaled
              points.

       [1m\V[4m[22me[0m
       [1m\V([4m[22mev[0m
       [1m\V[[4m[22menv[24m[1m][0m
              Interpolate  contents  of  the  environment variable [4menv[24m, as re‐
              turned by [4mgetenv[24m(3).  [1m\V [22mis interpreted even in copy mode.

       [1m\X'[4m[22manything[24m[1m'[0m
              Within [1m\X [22marguments, the escape sequences [1m\&[22m, [1m\)[22m, [1m\%[22m, and [1m\: [22mare
              ignored; [1m\[4m[22mspace[24m and [1m\~ [22mare converted to single space characters;
              and [1m\\ [22mis reduced to [1m\[22m.  So that the basic Latin subset  of  the
              Unicode  character set (that is, ISO 646:1991‐IRV or, popularly,
              “US‐ASCII”) can be reliably encoded  in  [4manything,[24m  the  special
              character  escape  sequences  [1m\-[22m,  [1m\[aq][22m,  [1m\[dq][22m,  [1m\[ga][22m, [1m\[ha][22m,
              [1m\[rs][22m, and [1m\[ti] [22mare  mapped  to  basic  Latin  characters;  see
              [4mgroff_char[24m(7).   For this transformation, character translations
              and definitions are ignored.  Other  escape  sequences  are  not
              supported.

              If  the [1muse_charnames_in_special [22mdirective appears in the output
              device’s [4mDESC[24m file, the use  of  special  character  escape  se‐
              quences  is  [4mnot[24m an error; they are simply output verbatim (with
              the exception of the seven mapped to Unicode basic Latin charac‐
              ters, discussed above).  [1muse_charnames_in_special  [22mis  currently
              employed only by [4mgrohtml[24m(1).

       [1m\Y[4m[22mm[0m
       [1m\Y([4m[22mma[0m
       [1m\Y[[4m[22mmac[24m[1m][0m
              Interpolate  a macro as a device control command.  This is simi‐
              lar to [1m\X'\*[[4m[22mmac[24m[1m]'[22m, except the contents of [4mmac[24m  are  not  inter‐
              preted,  and  [4mmac[24m  can  be  a  macro  and thus contain newlines,
              whereas the argument to [1m\X [22mcannot.  This inclusion  of  newlines
              requires  an extension to the AT&T [4mtroff[24m output format, and will
              confuse postprocessors that do not know about it.

       [1m\Z'[4m[22manything[24m[1m'[0m
              Save the drawing position, format  [4manything[24m,  then  restore  it.
              Tabs and leaders in the argument are ignored with an error diag‐
              nostic.

       [1m\#     [22mEverything  up  to  and  including  the next newline is ignored.
              This escape sequence is interpreted even in copy  mode.   [1m\#  [22mis
              like  [1m\"[22m,  except  that [1m\" [22mdoes not ignore a newline; the latter
              therefore cannot be used by itself for a  whole‐line  comment—it
              leaves a blank line on the input stream.

       [1m\$0    [22mInterpolate  the  name  by which the macro being interpreted was
              called.  In GNU [4mtroff[24m this name can vary; see the [1mals [22mrequest.

       [1m\$([4m[22mnn[0m
       [1m\$[[4m[22mnnn[24m[1m][0m
              In a macro or string definition, interpolate the [4mnn[24mth  or  [4mnnn[24mth
              argument.   Macros  and  strings can have an unlimited number of
              arguments.

       [1m\$*    [22mIn a macro or string definition, interpolate the  catenation  of
              all arguments, separated by spaces.

       [1m\$@    [22mIn  a  macro or string definition, interpolate the catenation of
              all arguments, with each surrounded by double quotes  and  sepa‐
              rated by spaces.

       [1m\$^    [22mIn  a  macro or string definition, interpolate the catenation of
              all arguments constructed in a form suitable for passage to  the
              [1mds [22mrequest.

       [1m\)     [22mInterpolate a [4mtransparent[24m dummy character—one that is ignored by
              end‐of‐sentence  detection.  It behaves as [1m\&[22m, except that [1m\& [22mis
              treated as letters and numerals normally are after “.”, “?”, and
              “!”; [1m\& [22mcancels end‐of‐sentence detection, and [1m\) [22mdoes not.

       [1m\*[[4m[22mstring[24m [[4marg[24m ...][1m][0m
              Interpolate [4mstring,[24m passing it [4marg[24m ... as arguments.

       [1m\/     [22mApply an [4mitalic[24m [4mcorrection[24m: modify the spacing of the  preceding
              glyph so that the distance between it and the following glyph is
              correct  if  the latter is of upright shape.  For example, if an
              italic “f” is followed immediately by a roman right parenthesis,
              then in many fonts the top right portion of the “f” overlaps the
              top left of the right parenthesis, which is ugly.  Inserting  [1m\/[0m
              between  them  avoids  this  problem.   Use this escape sequence
              whenever an oblique glyph is immediately followed by an  upright
              glyph without any intervening space.

       [1m\,     [22mApply  a  [4mleft[24m [4mitalic[24m [4mcorrection[24m: modify the spacing of the fol‐
              lowing glyph so that the distance between it and  the  preceding
              glyph  is  correct if the latter is of upright shape.  For exam‐
              ple, if a roman left parenthesis is immediately followed  by  an
              italic  “f”,  then  in  many  fonts  the  bottom left portion of
              the “f” overlaps the bottom of the left  parenthesis,  which  is
              ugly.   Inserting [1m\, [22mbetween them avoids this problem.  Use this
              escape sequence whenever an upright glyph  is  followed  immedi‐
              ately by an oblique glyph without any intervening space.

       [1m\:     [22mInsert  a  non‐printing  break point.  That is, a word can break
              there, but the soft hyphen character does  not  mark  the  break
              point if it does (in contrast to “[1m\%[22m”).  This escape sequence is
              an  input word boundary, so the remainder of the word is subject
              to hyphenation as normal.

       [1m\?[4m[22manything[24m[1m\?[0m
              When used in a diversion, this transparently embeds [4manything[24m  in
              the  diversion.  [4manything[24m is read in copy mode.  When the diver‐
              sion is reread, [4manything[24m is interpreted.  [4manything[24m may not  con‐
              tain  newlines; use [1m\! [22mif you want to embed newlines in a diver‐
              sion.  The escape sequence [1m\? [22mis also recognized  in  copy  mode
              and  becomes  an  internal code; it is this code that terminates
              [4manything[24m.  Thus

                     .nr x 1
                     .nf
                     .di d
                     \?\\?\\\\?\\\\\\\\nx\\\\?\\?\?
                     .di
                     .nr x 2
                     .di e
                     .d
                     .di
                     .nr x 3
                     .di f
                     .e
                     .di
                     .nr x 4
                     .f

              prints [1m4[22m.

       [1m\[[4m[22mchar[24m[1m][0m
              Typeset the special character [4mchar[24m.

       [1m\[[4m[22mbase‐char[24m [4mcombining‐component[24m ...[1m][0m
              Typeset a composite glyph consisting of [4mbase‐char[24m overlaid  with
              one  or  more [4mcombining‐component[24ms.  For example, “[1m\[A ho][22m” is a
              capital letter “A” with  a  “hook  accent”  (ogonek).   See  the
              [1mcomposite [22mrequest below; [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m,
              the  [4mgroff[24m  Texinfo  manual, for details of composite glyph name
              construction; and [4mgroff_char[24m(7) for a list of components used in
              composite glyph names.

       [1m\~     [22mInsert an unbreakable space that is adjustable like an  ordinary
              space.   It  is  discarded  from  the end of an output line if a
              break is forced.

   [1mRestricted requests[0m
       To mitigate risks from untrusted input documents, the  [1mpi  [22mand  [1msy  [22mre‐
       quests  are disabled by default.  [4mtroff[24m(1)’s [1m-U [22moption enables the for‐
       matter’s “unsafe mode”, restoring their function  (and  enabling  addi‐
       tional [4mgroff[24m extension requests, [1mopen[22m, [1mopena[22m, and [1mpso[22m).

   [1mNew requests[0m
       [1m.aln [4m[22mnew[24m [4mold[0m
              Create  alias  [4mnew[24m  for existing register named [4mold[24m, causing the
              names to refer to the same stored value.  If [4mold[24m is undefined, a
              warning in category “[1mreg[22m” is generated and the  request  is  ig‐
              nored.   To  remove  a register alias, invoke [1mrr [22mon its name.  A
              register’s contents do not become inaccessible until it  has  no
              more names.

       [1m.als [4m[22mnew[24m [4mold[0m
              Create  alias [4mnew[24m for existing request, string, macro, or diver‐
              sion named [4mold[24m, causing the names to refer to  the  same  stored
              object.   If  [4mold[24m  is  undefined, a warning in category “[1mmac[22m” is
              produced, and the request is ignored.  The “[1mam[22m”, “[1mas[22m”,  [1mda[22m,  [1mde[22m,
              [1mdi[22m,  and [1mds [22mrequests (together with their variants) create a new
              object only if the name of the macro, diversion,  or  string  is
              currently  undefined or if it is defined as a request; normally,
              they modify the value of  an  existing  object.   To  remove  an
              alias,  invoke  [1mrm  [22mon  its  name.  The object itself is not de‐
              stroyed until it has no more names.

              When a request, macro, string, or diversion is aliased, redefin‐
              itions and appendments “write through” alias names.  To  replace
              an  alias  with a separately defined object, you must use the [1mrm[0m
              request on its name first.

       [1m.am1 [4m[22mname[24m [[4mend‐name[24m]
              As “[1mam[22m”, but compatibility mode is disabled while the appendment
              to [4mname[24m is interpreted: a “compatibility save” token is inserted
              at its beginning, and a “compatibility  restore”  token  at  its
              end.   As a consequence, the requests “[1mam[22m”, [1mam1[22m, [1mde[22m, and [1mde1 [22mcan
              be intermixed freely since the compatibility save/restore tokens
              affect only the parts of the macro populated by [1mam1 [22mand [1mde1[22m.

       [1m.ami [4m[22mname[24m [[4mend‐name[24m]
              Append to macro indirectly.  See [1mdei [22mbelow.

       [1m.ami1 [4m[22mname[24m [[4mend‐name[24m]
              As [1mami[22m, but compatibility mode is disabled during interpretation
              of the appendment.

       [1m.as1 [4m[22mname[24m [[4mcontents[24m]
              As “[1mas[22m”, but compatibility mode is disabled while the appendment
              to [4mname[24m is interpreted: a “compatibility save” token is inserted
              at the beginning of [4mcontents[24m, and a “compatibility restore”  to‐
              ken after it.  As a consequence, the requests “[1mas[22m”, [1mas1[22m, [1mds[22m, and
              [1mds1  [22mcan  be  intermixed freely since the compatibility save/re‐
              store tokens affect only the portions of the  strings  populated
              by [1mas1 [22mand [1mds1[22m.

       [1m.asciify [4m[22mdiv[0m
              [4mUnformat[24m  the  diversion  [4mdiv[24m  in  a way such that Unicode basic
              Latin (ASCII) characters, characters translated  with  the  [1mtrin[0m
              request,  space characters, and some escape sequences, that were
              formatted in the diversion [4mdiv[24m are treated like  ordinary  input
              characters  when  [4mdiv[24m is reread.  Doing so can be useful in con‐
              junction with the [1mwritem [22mrequest.  [1masciify [22mcan be also used  for
              gross hacks; for example, the following sets register [1mn [22mto 1.

                     .tr @.
                     .di x
                     @nr n 1
                     .br
                     .di
                     .tr @@
                     .asciify x
                     .x

              [1masciify  [22mcannot  return all items in a diversion to their source
              equivalent: nodes such as those produced by [1m\N[[22m...[1m] [22mwill  remain
              nodes,  so  the result cannot be guaranteed to be a pure string.
              See section “Copy mode” in [4mgroff[24m(7).  Glyph parameters  such  as
              the  type  face  and  size  are  not  preserved; use [1munformat [22mto
              achieve that.

       [1m.backtrace[0m
              Write backtrace of input stack to  the  standard  error  stream.
              See the [1m-b [22moption of [4mtroff[24m(1).

       [1m.blm [22m[[4mname[24m]
              Set  a  blank  line macro (trap).  If a blank line macro is thus
              defined, [4mgroff[24m executes [4mmacro[24m when a blank line  is  encountered
              in  the  input file, instead of the usual behavior.  A line con‐
              sisting only of spaces is also treated as blank and  subject  to
              this  trap.   If no argument is supplied, the default blank line
              behavior is (re‐)established.

       [1m.box [22m[[4mname[24m]
       [1m.boxa [22m[[4mname[24m]
              Divert (or append) output to [4mname,[24m similarly to the  [1mdi  [22mand  [1mda[0m
              requests, respectively.  Any pending output line is [4mnot[24m included
              in  the  diversion.  Without an argument, stop diverting output;
              any pending output line inside the diversion is discarded.

       [1m.break [22mExit a “[1mwhile[22m” loop.  Do not confuse this request with  a  typo‐
              graphical break or the [1mbr [22mrequest.  See “[1mcontinue[22m”.

       [1m.brp   [22mBreak and adjust line; this is the AT&T [4mtroff[24m escape sequence [1m\p[0m
              in request form.

       [1m.cflags [4m[22mn[24m [4mc1[24m [4mc2[24m ...
              Assign  properties encoded by the number [4mn[24m to characters [4mc1[24m, [4mc2[24m,
              and so on.  Ordinary and special characters have certain associ‐
              ated properties.  (Glyphs don’t: to GNU [4mtroff[24m, like AT&T device‐
              independent [4mtroff[24m, a glyph is an identifier corresponding  to  a
              rectangle  with some metrics; see [4mgroff_font[24m(5).)  The first ar‐
              gument is the sum of the desired flags and the  remaining  argu‐
              ments  are  the  characters  to  be  assigned  those properties.
              Spaces between the [4mcn[24m arguments are optional.  Any  argument  [4mcn[0m
              can  be  a character class defined with the [1mclass [22mrequest rather
              than an individual character.

              The non‐negative integer [4mn[24m is the sum of any of  the  following.
              Some combinations are nonsensical, such as “[1m33[22m” (1 + 32).

              1      Recognize  the character as ending a sentence if followed
                     by a newline or two spaces.  Initially, characters  “[1m.?![22m”
                     have this property.

              2      Enable breaks before the character.  A line is not broken
                     at  a  character with this property unless the characters
                     on each side both have non‐zero hyphenation codes.   This
                     exception  can be overridden by adding 64.  Initially, no
                     characters have this property.

              4      Enable breaks after the character.  A line is not  broken
                     at  a  character with this property unless the characters
                     on each side both have non‐zero hyphenation codes.   This
                     exception  can  be  overridden  by adding 64.  Initially,
                     characters “[1m-\[hy]\[em][22m” have this property.

              8      Mark the glyph associated with this character as overlap‐
                     ping other instances of itself horizontally.   Initially,
                     characters   “[1m\[ul]\[rn]\[ru]\[radicalex]\[sqrtex][22m”  have
                     this property.

              16     Mark the glyph associated with this character as overlap‐
                     ping other instances of  itself  vertically.   Initially,
                     the character “[1m\[br][22m” has this property.

              32     Mark the character as transparent for the purpose of end‐
                     of‐sentence  recognition.  In other words, an end‐of‐sen‐
                     tence character followed by any number of characters with
                     this property is treated as the end of a sentence if fol‐
                     lowed by a newline or two spaces.  This is  the  same  as
                     having a zero space factor in TeX.  Initially, characters
                     “[1m'")]*\[dg]\[dd]\[rq]\[cq][22m” have this property.

              64     Ignore  hyphenation  codes of the surrounding characters.
                     Use this value in combination with values 2 and 4.   Ini‐
                     tially, no characters have this property.

                     For  example,  if you need an automatic break point after
                     the en‐dash in numeric ranges like “3000–5000”, insert
                            .cflags 68 \[en]
                     into your document.  However, this can lead to bad layout
                     if done without thinking; in most  situations,  a  better
                     solution than changing the [1mcflags [22mvalue is inserting “[1m\:[22m”
                     right  after  the hyphen at the places that really need a
                     break point.

              The remaining values were implemented for  East  Asian  language
              support; those who use alphabetic scripts exclusively can disre‐
              gard them.

              128    Prohibit  a break before the character, but allow a break
                     after the character.  This works only in combination with
                     values 256 and 512 and has  no  effect  otherwise.   Ini‐
                     tially, no characters have this property.

              256    Prohibit  a  break after the character, but allow a break
                     before the character.  This  works  only  in  combination
                     with  values  128  and  512  and has no effect otherwise.
                     Initially, no characters have this property.

              512    Allow a break before or after the character.  This  works
                     only  in  combination  with values 128 and 256 and has no
                     effect otherwise.  Initially,  no  characters  have  this
                     property.

              In contrast to values 2 and 4, the values 128, 256, and 512 work
              pairwise.   If,  for  example, the left character has value 512,
              and the right character 128, no break will be automatically  in‐
              serted  between  them.   If  we use value 6 instead for the left
              character, a break after the character can’t be suppressed since
              the neighboring character on the right doesn’t get examined.

       [1m.char [4m[22mc[24m [4mcontents[0m
              Define the ordinary or special character [4mc[24m  as  [4mcontents[24m,  which
              can  be  empty.  More precisely, [1mchar [22mdefines a [4mgroff[24m object (or
              redefines an existing one) that is accessed with the name  [4mc[24m  on
              input,  and  produces [4mcontents[24m on output.  Every time [4mc[24m is to be
              formatted, [4mcontents[24m is processed in a temporary environment  and
              the  result  is  wrapped up into a single object.  Compatibility
              mode is turned off and the escape character is set  to  [1m\  [22mwhile
              [4mcontents[24m  is  processed.   Any emboldening, constant spacing, or
              track kerning is applied to this object as a whole, not to  each
              character in [4mcontents[24m.

              An  object defined by this request can be used just like a glyph
              provided by the output device.  In particular, other  characters
              can  be translated to it with the [1mtr [22mrequest; it can be made the
              tab or leader fill character with the [1mtc [22mand  [1mlc  [22mrequests;  se‐
              quences  of it can be drawn with the [1m\l [22mand [1m\L [22mescape sequences;
              and, if the [1mhcode [22mrequest is used on [4mc[24m, it is subject  to  auto‐
              matic hyphenation.

              To  prevent  infinite recursion, occurrences of [4mc[24m within its own
              definition are treated normally (as if it were not being defined
              with [1mchar[22m).  The [1mtr [22mand [1mtrin [22mrequests take  precedence  if  [1mchar[0m
              both apply to [4mc[24m.  A character definition can be removed with the
              [1mrchar [22mrequest.

       [1m.chop [4m[22mobject[0m
              Remove  the  last character from the macro, string, or diversion
              [4mobject[24m.  This is useful for removing the newline from the end of
              a diversion that is to be interpolated as a  string.   This  re‐
              quest  can  be  used  repeatedly on the same [4mobject[24m; see section
              “gtroff Internals” in [4mGroff:[24m [4mThe[24m [4mGNU[24m  [4mImplementation[24m  [4mof[24m  [4mtroff[24m,
              the  [4mgroff[24m  Texinfo  manual, for discussion of nodes inserted by
              [4mgroff[24m.

       [1m.class [4m[22mname[24m [4mc1[24m [4mc2[24m ...
              Define a character class (or simply “class”) [4mname[24m comprising the
              characters or range expressions [4mc1[24m, [4mc2[24m, and so on.

              A class thus defined can then be referred to in lieu of  listing
              all  the  characters  within it.  Currently, only the [1mcflags [22mre‐
              quest can handle references to character classes.

              In the request’s simplest form, each [4mcn[24m is a character (or  spe‐
              cial character).
                     .class [quotes] ' \[aq] \[dq] \[oq] \[cq] \[lq] \[rq]

              Since  class  and  special  character  names share the same name
              space, we recommend starting and ending the class name with  “[1m[[22m”
              and “[1m][22m”, respectively, to avoid collisions with existing charac‐
              ter  names  defined  by [4mgroff[24m or the user (with [1mchar [22mand related
              requests).  This practice applies the presence  of  “[1m][22m”  in  the
              class  name to prevent the usage of the special character escape
              form “[1m\[[22m...[1m][22m”, thus you must use the [1m\C [22mescape to access a class
              with such a name.

              You can also use a character range expression  consisting  of  a
              start  character followed by “[1m-[22m” and then an end character.  In‐
              ternally, GNU [4mtroff[24m converts these two character names  to  Uni‐
              code  code  points  (according  to  the [4mgroff[24m glyph list [GGL]),
              which determine the start and end values of the range.  If  that
              fails,  the  class  definition is skipped.  Furthermore, classes
              can be nested.
                     .class [prepunct] , : ; > }
                     .class [prepunctx] \C'[prepunct]' \[u2013]-\[u2016]
              The class “[1m[prepunctx][22m” thus contains the contents of the  class
              “[1m[prepunct][22m” and characters in the range U+2013–U+2016.

              If  you  want  to  include  “[1m-[22m” in a class, it must be the first
              character value in the argument list, otherwise it  gets  misin‐
              terpreted as part of the range syntax.

              It is not possible to use class names as end points of range de‐
              finitions.

              A  typical  use of the [1mclass [22mrequest is to control line‐breaking
              and hyphenation rules as defined by the [1mcflags [22mrequest.  For ex‐
              ample, to inhibit line breaks before the characters belonging to
              the “[1m[prepunctx][22m” class defined in the previous example, you can
              write the following.
                     .cflags 2 \C'[prepunctx]'

       [1m.close [4m[22mstream[0m
              Close the stream named [4mstream[24m, invalidating it as an argument to
              the [1mwrite [22mrequest.  See [1mopen[22m.

       [1m.composite [4m[22mc1[24m [4mc2[0m
              Map character name [4mc1[24m to character name [4mc2[24m when [4mc1[24m is a  combin‐
              ing  component  in  a composite glyph.  Typically, this remaps a
              spacing glyph to a combining one.

       [1m.continue[0m
              Skip the remainder of a “[1mwhile[22m” loop’s body, immediately  start‐
              ing the next iteration.  See [1mbreak[22m.

       [1m.color [4m[22mn[0m
              If [4mn[24m is non‐zero or missing, enable colors (the default), other‐
              wise disable them.

       [1m.cp [4m[22mn[24m  If  [4mn[24m  is non‐zero or missing, enable compatibility mode, other‐
              wise disable it.  In compatibility mode, long names are not rec‐
              ognized, and the incompatibilities they cause do not arise.

       [1m.defcolor [4m[22mident[24m [4mscheme[24m [4mcolor‐component[24m ...
              Define a color named [4mident.[24m  [4mscheme[24m identifies a color space and
              determines the number of required [4mcolor‐component[24ms; it  must  be
              one  of  “[1mrgb[22m”  (three  components),  “[1mcmy[22m”  (three components),
              “[1mcmyk[22m” (four components), or “[1mgray[22m” (one component).  “[1mgrey[22m”  is
              accepted  as  a  synonym of “[1mgray[22m”.  The color components can be
              encoded as a hexadecimal value starting with [1m# [22mor [1m##[22m.  The  for‐
              mer  indicates that each component is in the range 0–255 (0–FF),
              the latter the  range  0–65535  (0–FFFF).   Alternatively,  each
              color  component  can  be specified as a decimal fraction in the
              range 0–1, interpreted using a  default  scaling  unit  of  “[1mf[22m”,
              which multiplies its value by 65,536 (but clamps it at 65,535).

              Each  output device has a color named “[1mdefault[22m”, which cannot be
              redefined.  A device’s default stroke and fill  colors  are  not
              necessarily the same.

       [1m.de1 [4m[22mname[24m [[4mend‐name[24m]
              Define  a  macro  to be interpreted with compatibility mode dis‐
              abled.  When [4mname[24m is called, compatibility mode enablement  sta‐
              tus is saved; it is restored when the call completes.

       [1m.dei [4m[22mname[24m [[4mend‐name[24m]
              Define  macro  indirectly,  with the name of the macro to be de‐
              fined in string [4mname[24m and the name of the end  macro  terminating
              its definition in string [4mend‐name[24m.

       [1m.dei1 [4m[22mname[24m [[4mend‐name[24m]
              As  [1mdei[22m, but compatibility mode is disabled while the definition
              of the macro named in string [4mname[24m is interpreted.

       [1m.device [4m[22manything[0m
              Write [4manything[24m, read in copy mode, to [4mtroff[24m output as  a  device
              control command.  An initial neutral double quote is stripped to
              allow the embedding of leading spaces.

       [1m.devicem [4m[22mname[0m
              Write  contents of macro or string [4mname[24m to [4mtroff[24m output as a de‐
              vice control command.

       [1m.do [4m[22mname[24m [[4marg[24m ...]
              Interpret the string, request, diversion, or macro  [4mname[24m  (along
              with  any arguments) with compatibility mode disabled.  Compati‐
              bility mode is restored (only if it was active) when the  [4mexpan‐[0m
              [4msion[24m of [4mname[24m is interpreted; that is, the restored compatibility
              state applies to the contents of the macro, string, or diversion
              [4mname[24m  as well as data read from files or pipes if [4mname[24m is any of
              the [1mso[22m, [1msoquiet[22m, [1mmso[22m, [1mmsoquiet[22m, or [1mpso [22mrequests.

              For example,
                     .de mac1
                     FOO
                     ..
                     .de1 mac2
                     groff
                     .mac1
                     ..
                     .de mac3
                     compatibility
                     .mac1
                     ..
                     .de ma
                     \\$1
                     ..
                     .cp 1
                     .do mac1
                     .do mac2 \" mac2, defined with .de1, calls "mac1"
                     .do mac3 \" mac3 calls "ma" with argument "c1"
                     .do mac3 \[ti] \" groff syntax accepted in .do arguments
              results in
                     FOO groff FOO compatibility c1 ~
              as output.

       [1m.ds1 [4m[22mname[24m [4mcontents[0m
              As [1mds[22m, but compatibility mode is disabled while [4mname[24m  is  inter‐
              preted:  a  “compatibility save” token is inserted at the begin‐
              ning of [4mcontents[24m, and a “compatibility restore” token after it.

       [1m.ecr   [22mRestore the escape character saved with [1mecs[22m, or set escape char‐
              acter to “[1m\[22m” if none has been saved.

       [1m.ecs   [22mSave the current escape character.

       [1m.evc [4m[22menv[0m
              Copy the properties of environment [4menv[24m to the  current  environ‐
              ment, except for the following data.

              • a partially collected line, if present;

              • the interruption status of the previous input line (due to use
                of the [1m\c [22mescape sequence);

              • the  count  of remaining lines to center, to right‐justify, or
                to underline (with or without underlined spaces)—these are set
                to zero;

              • the activation status of temporary indentation;

              • input traps and their associated data;

              • the activation status of line numbering (which can be  reacti‐
                vated with “[1m.nm +0[22m”); and

              • the count of consecutive hyphenated lines (set to zero).

       [1m.fam [22m[[4mfamily[24m]
              Set default font family to [4mfamily[24m.  If no argument is given, the
              previous  font  family  is  selected, or the formatter’s default
              family if there is none.  The formatter’s default font family is
              “T” (Times), but it can be overridden by the  output  device—see
              [4mgroff_font[24m(5).   The  default font family is associated with the
              environment.  See [1m\F[22m.

       [1m.fchar [4m[22mc[24m [4mcontents[0m
              Define fallback character [4mc[24m as [4mcontents[24m.  The syntax of this re‐
              quest is the same as the [1mchar [22mrequest; the difference is that  a
              character  defined with [1mchar [22mhides a glyph with the same name in
              the selected font, whereas characters  defined  with  [1mfchar  [22mare
              checked  only  if [4mc[24m isn’t found in the selected font.  This test
              happens before special fonts are searched.

       [1m.fcolor [4m[22mcolor[0m
              Set the fill color to [4mcolor[24m.  Without an argument, the  previous
              fill color is selected.

       [1m.fschar [4m[22mf[24m [4mc[24m [4mcontents[0m
              Define  fallback  special character [4mc[24m for font [4mf[24m as [4mcontents[24m.  A
              character defined by [1mfschar [22mis located after the list  of  fonts
              declared  with  [1mfspecial  [22mis  searched but before those declared
              with the “[1mspecial[22m” request.

       [1m.fspecial [4m[22mf[24m [4ms1[24m [4ms2[24m ...
              When font [4mf[24m is selected, fonts [4ms1[24m, [4ms2[24m, ... are treated  as  spe‐
              cial; that is, they are searched for glyphs not found in [4mf[24m.  Any
              fonts  specified in the “[1mspecial[22m” request are searched after [4ms1[24m,
              [4ms2[24m, and so on.  Without [4ms[24m arguments, [1mfspecial [22mclears the list of
              fonts treated as special when [4mf[24m is selected.

       [1m.ftr [4m[22mf[24m [4mg[0m
              Translate font [4mf[24m to [4mg[24m.  Whenever a font named [4mf[24m is  referred  to
              in  an [1m\f [22mescape sequence, in the [1mF [22mand [1mS [22mconditional expression
              operators, or in the [1mft[22m, [1mul[22m, [1mbd[22m, [1mcs[22m, [1mtkf[22m, [1mspecial[22m, [1mfspecial[22m, [1mfp[22m,
              or [1msty [22mrequests, font [4mg[24m is used.  If [4mg[24m is missing  or  identical
              to [4mf[24m, then font [4mf[24m is not translated.

       [1m.fzoom [4m[22mf[24m [4mzoom[0m
              Set zoom factor [4mzoom[24m for font [4mf[24m.  [4mzoom[24m must a non‐negative inte‐
              ger multiple of 1/1000th.  If it is missing or is equal to zero,
              it means the same as 1000, namely no magnification.  [4mf[24m must be a
              resolved font name, not an abstract style.

       [1m.gcolor [4m[22mcolor[0m
              Set  the stroke color to [4mcolor[24m.  Without an argument, the previ‐
              ous stroke color is selected.

       [1m.hcode [4m[22mc1[24m [4mcode1[24m [[4mc2[24m [4mcode2[24m] ...
              Set the hyphenation code of character [4mc1[24m to [4mcode1[24m, that of [4mc2[24m to
              [4mcode2[24m, and so on.  A hyphenation code must be an ordinary  char‐
              acter  (not  a  special  character escape sequence) other than a
              digit.  The request is ignored if given no arguments.

              For hyphenation to work, hyphenation codes must be set  up.   At
              startup,  [4mgroff[24m  assigns  hyphenation codes to the letters “a–z”
              (mapped to themselves), to the letters “A–Z” (mapped to  “a–z”),
              and  zero  to  all other characters.  Normally, hyphenation pat‐
              terns contain only lowercase letters which should be applied re‐
              gardless of case.  In other words, they assume  that  the  words
              “ABBOT”  and “Abbot” should be hyphenated exactly as “abbot” is.
              [1mhcode [22mextends this principle to letters outside the Unicode  ba‐
              sic  Latin  alphabet;  without it, words containing such letters
              won’t be hyphenated properly even if the  corresponding  hyphen‐
              ation patterns contain them.

       [1m.hla [4m[22mlang[0m
              Set  the  hyphenation  language to [4mlang[24m.  Hyphenation exceptions
              specified with the [1mhw [22mrequest and hyphenation patterns  and  ex‐
              ceptions specified with the [1mhpf [22mand [1mhpfa [22mrequests are associated
              with  the  hyphenation language.  The [1mhla [22mrequest is usually in‐
              voked by a localization file, which is in  turn  loaded  by  the
              [4mtroffrc[24m or [4mtroffrc-end[24m file; see the [1mhpf [22mrequest below.  The hy‐
              phenation language is associated with the environment.

       [1m.hlm [22m[[4mn[24m]
              Set the maximum number of consecutive hyphenated lines to [4mn[24m.  If
              [4mn[24m  is negative, there is no maximum.  If omitted, [4mn[24m is -1.  This
              value is associated with the  environment.   Only  lines  output
              from  a  given  environment count towards the maximum associated
              with that environment.  Hyphens resulting from [1m\%  [22mare  counted;
              explicit hyphens are not.

       [1m.hpf [4m[22mpattern‐file[0m
              Read  hyphenation  patterns  from  [4mpattern‐file[24m.   This  file is
              sought in the same way that macro files are with the [1mmso [22mrequest
              or the [1m-m[4m[22mname[24m command‐line option to [4mgroff[24m(1) and [4mtroff[24m(1).

              The [4mpattern‐file[24m should have the same  format  as  (simple)  TeX
              pattern files.  The following scanning rules are implemented.

              • A  percent  sign  starts a comment (up to the end of the line)
                even if preceded by a backslash.

              • “Digraphs” like [1m\$ [22mare not supported.

              • “[1m^^[4m[22mxx[24m” (where each [4mx[24m is 0–9 or a–f) and [1m^^[4m[22mc[24m  (character  [4mc[24m  in
                the code point range 0–127 decimal) are recognized; other uses
                of [1m^ [22mcause an error.

              • No macro expansion is performed.

              • [1mhpf  [22mchecks  for  the expression [1m\patterns{[22m...[1m} [22m(possibly with
                whitespace before or after the  braces).   Everything  between
                the  braces  is  taken as hyphenation patterns.  Consequently,
                “[1m{[22m” and “[1m}[22m” are not allowed in patterns.

              • Similarly, [1m\hyphenation{[22m...[1m} [22mgives a list of  hyphenation  ex‐
                ceptions.

              • [1m\endinput [22mis recognized also.

              • For  backwards  compatibility,  if  [1m\patterns  [22mis missing, the
                whole file is treated as a list of hyphenation  patterns  (but
                the  “[1m%[22m”  character is still recognized as the start of a com‐
                ment).

              Use the [1mhpfcode [22mrequest (see below) to map the encoding used  in
              hyphenation pattern files to [4mgroff[24m’s input encoding.

              The  set  of hyphenation patterns is associated with the hyphen‐
              ation language set by the [1mhla [22mrequest.  The [1mhpf [22mrequest is  usu‐
              ally  invoked by a localization file loaded by the [4mtroffrc[24m file.
              By default, [4mtroffrc[24m loads the  localization  file  for  English.
              (As  of  [4mgroff[24m 1.23.0, localization files for Czech ([4mcs[24m), German
              ([4mde[24m), English ([4men[24m), French ([4mfr[24m), Japanese  ([4mja[24m),  Swedish  ([4msv[24m),
              and  Chinese  ([4mzh[24m) exist.)  For Western languages, the localiza‐
              tion file sets the hyphenation mode and loads  hyphenation  pat‐
              terns and exceptions.

              A  second  call  to [1mhpf [22m(for the same language) replaces the old
              patterns with the new ones.

              Invoking [1mhpf [22mcauses an error if there  is  no  hyphenation  lan‐
              guage.

              If  no  [1mhpf  [22mrequest  is specified (either in the document, in a
              file loaded at startup, or in a macro package), GNU [4mtroff[24m  won’t
              automatically hyphenate at all.

       [1m.hpfa [4m[22mpattern‐file[0m
              As [1mhpf[22m, except that the hyphenation patterns and exceptions from
              [4mpattern‐file[24m are appended to the patterns already applied to the
              hyphenation language of the environment.

       [1m.hpfcode [4m[22ma[24m [4mb[24m [[4mc[24m [4md[24m] ...
              Define  mapping  values  for  character  codes in pattern files.
              This is an older mechanism no longer used by [4mgroff[24m’s  own  macro
              files;  for  its  successor, see [1mhcode [22mabove.  [1mhpf [22mor [1mhpfa [22mapply
              the mapping after reading or appending to  the  active  list  of
              patterns.   Its  arguments are pairs of character codes—integers
              from 0 to 255.  The request maps character code  [4ma[24m  to  code  [4mb[24m,
              code  [4mc[24m to code [4md[24m, and so on.  Character codes that would other‐
              wise be invalid in [4mgroff[24m can be used.  By  default,  every  code
              maps to itself except those for letters “A” to “Z”, which map to
              those for “a” to “z”.

       [1m.hym [22m[[4mlength[24m]
              Set the (right) hyphenation margin to [4mlength[24m.  If the adjustment
              mode  is  not  “[1mb[22m”  or  “[1mn[22m”, the line is not hyphenated if it is
              shorter than [4mlength[24m.  Without an argument, the  default  hyphen‐
              ation  margin  is  reset  to  its default value, 0.  The default
              scaling unit is “[1mm[22m”.  The hyphenation margin is associated  with
              the  environment.   A  negative  argument resets the hyphenation
              margin to zero, emitting a warning in category “[1mrange[22m”.

       [1m.hys [22m[[4mhyphenation‐space[24m]
              Suppress hyphenation of the line in adjustment modes “[1mb[22m” or “[1mn[22m”,
              if it can be justified by adding no more than  [4mhyphenation‐space[0m
              extra  space to each inter‐word space.  Without an argument, the
              hyphenation space adjustment threshold is  set  to  its  default
              value,  0.   The  default  scaling unit is “[1mm[22m”.  The hyphenation
              space adjustment threshold is associated with the current  envi‐
              ronment.   A  negative argument resets the hyphenation space ad‐
              justment threshold to  zero,  emitting  a  warning  in  category
              “[1mrange[22m”.

       [1m.itc [4m[22mn[24m [4mname[0m
              As  “[1mit[22m”,  but lines interrupted with the [1m\c [22mescape sequence are
              not applied to the line count.

       [1m.kern [4m[22mn[0m
              If [4mn[24m is non‐zero or missing, enable pairwise  kerning  (the  de‐
              fault), otherwise disable it.

       [1m.length [4m[22mreg[24m [4manything[0m
              Compute  the  number  of  characters  in [4manything[24m and return the
              count in the register [4mreg[24m.  If [4mreg[24m doesn’t exist, it is created.
              [4manything[24m is read in copy mode.

                     [1m.ds xxx abcd\h'3i'efgh[0m
                     [1m.length yyy \*[xxx][0m
                     [1m\n[yyy][0m
                     14

       [1m.linetabs [4m[22mn[0m
              If [4mn[24m is non‐zero or missing, enable  line‐tabs  mode,  otherwise
              disable  it (the default).  In this mode, tab stops are computed
              relative to the start of the pending output line, instead of the
              drawing position corresponding to the start of the  input  line.
              Line‐tabs mode is a property of the environment.

              For example, the following

                     .ds x a\t\c
                     .ds y b\t\c
                     .ds z c
                     .ta 1i 3i
                     \*x
                     \*y
                     \*z
              yields
                     a         b         c
              whereas in line‐tabs mode, the same input gives
                     a         b                   c
              instead.

       [1m.lsm [22m[[4mname[24m]
              Set  the leading space macro (trap) to [4mname[24m.  If there are lead‐
              ing space characters on an input line, [4mname[24m is invoked  in  lieu
              of the usual [4mroff[24m behavior; the leading spaces are removed.  The
              count  of  leading spaces on an input line is stored in [1m\n[lsn][22m,
              and the amount of corresponding horizontal  motion  in  [1m\n[lss][22m,
              irrespective  of  whether  a leading space trap is set.  When it
              is, the leading spaces are removed from the input line,  and  no
              motion  is produced before calling [4mname[24m.  If no argument is sup‐
              plied, the default leading space behavior is (re‐)established.

       [1m.mso [4m[22mfile[0m
              As “[1mso[22m”, except that [4mfile[24m is sought in the same  directories  as
              arguments  to  the  [4mgroff[24m(1) and [4mtroff[24m(1) [1m-m [22mcommand‐line option
              are (the “tmac path”).  If the file name to be interpolated  has
              the  form  [4mname[24m[1m.tmac  [22mand  it  isn’t found, [1mmso [22mtries to include
              [1mtmac.[4m[22mname[24m instead and vice versa.  If [4mfile[24m  does  not  exist,  a
              warning  in  category  “[1mfile[22m”  is emitted and the request has no
              other effect.

       [1m.msoquiet [4m[22mfile[0m
              As [1mmso[22m, but no warning is emitted if [4mfile[24m does not exist.

       [1m.nop [4m[22manything[0m
              Interpret [4manything[24m as if it were an input line.   [1mnop  [22mresembles
              “[1m.if  1[22m”;  it  puts  a break on the output if [4manything[24m is empty.
              Unlike “[1mif[22m”, it cannot govern conditional blocks.  Its  applica‐
              tion  is to maintain consistent indentation within macro defini‐
              tions even when producing text lines.

       [1m.nroff [22mMake the [1mn [22mconditional expression evaluate  true  and  [1mt  [22mfalse.
              See [1mtroff[22m.

       [1m.open [4m[22mstream[24m [4mfile[0m
              Open  [4mfile[24m  for writing and associate [4mstream[24m with it.  See [1mwrite[0m
              and [1mclose[22m.

       [1m.opena [4m[22mstream[24m [4mfile[0m
              As [1mopen[22m, but if [4mfile[24m exists, append to it instead of  truncating
              it.

       [1m.output [4m[22mcontents[0m
              Emit  [4mcontents[24m,  which  are  read in copy mode, to the formatter
              output; this is similar to [1m\! [22mused in the  top‐level  diversion.
              An initial neutral double quote in [4mcontents[24m is stripped to allow
              the embedding of leading spaces.

       [1m.pev   [22mReport  the state of the current environment followed by that of
              all other environments to the standard error stream.

       [1m.pnr   [22mWrite the names and values of all currently defined registers to
              the standard error stream.

       [1m.psbb [4m[22mfile[0m
              Get the bounding box of a PostScript image [4mfile[24m.  This file must
              conform to Adobe’s Document Structuring Conventions; the request
              attempts to extract the bounding box values from a [1m%%BoundingBox[0m
              comment.  After invocation, the [4mx[24m and [4my[24m  coordinates  (in  Post‐
              Script  units)  of the lower left and upper right corners can be
              found in the registers [1m\n[llx][22m, [1m\n[lly][22m, [1m\n[urx][22m,  and  [1m\n[ury][22m,
              respectively.   If an error occurs, these four registers are set
              to zero.

       [1m.pso [4m[22mcommand[0m
              As “[1mso[22m”, except that input comes from the standard output stream
              of [4mcommand[24m.

       [1m.ptr   [22mReport the names and vertical positions  of  all  page  location
              traps to the standard error stream.  Empty slots in the list are
              shown  as well, because they can affect the visibility of subse‐
              quently planted traps.

       [1m.pvs [4m[22m±n[0m
              Set the post‐vertical line spacing to [4mn[24m;  default  scaling  unit
              is  “[1mp[22m”.   With no argument, the post‐vertical line space is set
              to its previous value.

              In GNU [4mtroff[24m, the distance between text  baselines  consists  of
              the  extra pre‐vertical line spacing set by the most negative [1m\x[0m
              argument on the pending output line, the vertical spacing  ([1mvs[22m),
              the extra post‐vertical line spacing set by the most positive [1m\x[0m
              argument  on the pending output line, and the post‐vertical line
              spacing set by this request.

       [1m.rchar [4m[22mc[24m ...
              Remove definition of each ordinary or special character [4mc[24m, undo‐
              ing the effect of a [1mchar[22m,  [1mfchar[22m,  or  [1mschar  [22mrequest.   Glyphs,
              which  are defined by font description files, cannot be removed.
              Spaces and tabs may separate [4mc[24m arguments.

       [1m.return[0m
              Within a macro, return immediately.  If called with an argument,
              return twice, namely from the current macro and from  the  macro
              one level higher.  No effect otherwise.

       [1m.rfschar [4m[22mf[24m [4mc[24m ...
              Remove each fallback special character [4mc[24m for font [4mf[24m.  Spaces and
              tabs may separate [4mc[24m arguments.  See [1mfschar[22m.

       [1m.rj [22m[[4mn[24m]
              Right‐align the next [4mn[24m input lines.  Without an argument, right‐
              align  the  next input line.  [1mrj [22mimplies “[1m.ce 0[22m”, and [1mce [22mimplies
              “[1m.rj 0[22m”.

       [1m.rnn [4m[22mr1[24m [4mr2[0m
              Rename register [4mr1[24m to [4mr2[24m.  If [4mr1[24m doesn’t exist, the  request  is
              ignored.

       [1m.schar [4m[22mc[24m [4mcontents[0m
              Define  global  fallback character [4mc[24m as [4mcontents[24m.  See [1mchar[22m; the
              distinction is that a character defined with  [1mschar  [22mis  located
              after  the  list  of fonts declared with the [1mspecial [22mrequest but
              before any mounted special fonts.

       [1m.shc [22m[[4mc[24m]
              Set the soft hyphen character, inserted when a word  is  hyphen‐
              ated automatically or at a hyphenation character, to [4mc[24m.  If [4mc[24m is
              omitted, the soft hyphen character is set to the default, [1m\[hy][22m.
              If the selected glyph does not exist in the font in use at a po‐
              tential  hyphenation  point, then the line is not broken at that
              point.  Neither character definitions  ([1mchar  [22mand  similar)  nor
              translations  ([1mtr [22mand similar) are considered when assigning the
              soft hyphen character.

       [1m.shift [4m[22mn[0m
              In a macro, shift the arguments by [4mn[24m positions: argument  [4mi[24m  be‐
              comes  argument  [4mi[24m-[4mn[24m;  arguments 1 to [4mn[24m are no longer available.
              If [4mn[24m is missing, arguments are shifted by 1.  No  effect  other‐
              wise.

       [1m.sizes [4m[22ms1[24m [4ms2[24m ... [4msn[24m [[1m0[22m]
              Set  the  available  type sizes to [4ms1[24m, [4ms2[24m, ... [4msn[24m scaled points.
              The list of sizes can be terminated by an optional “[1m0[22m”.  Each [4msi[0m
              can also be a range [4mm[24m–[4mn[24m.  In contrast to the device  description
              file  directive  of the same name (see [4mgroff_font[24m(5)), the argu‐
              ment list can’t extend over more than one line.

       [1m.soquiet [4m[22mfile[0m
              As “[1mso[22m”, but no warning is emitted if [4mfile[24m does not exist.

       [1m.special [4m[22mf[24m ...
              Declare each font [4mf[24m as special,  searching  it  for  glyphs  not
              found  in  the  selected  font.  Without arguments, this list of
              special fonts is made empty.

       [1m.spreadwarn [22m[[4mlimit[24m]
              Emit a [1mbreak [22mwarning if the additional space inserted  for  each
              space  between  words in an output line adjusted to both margins
              with “[1m.ad b[22m” is larger than or equal to [4mlimit[24m.  A negative value
              is treated as zero; an absent argument toggles  the  warning  on
              and  off without changing [4mlimit[24m.  The default scaling unit is [1mm[22m.
              At startup, [1mspreadwarn [22mis inactive and [4mlimit[24m is 3 m.

              For example, “[1m.spreadwarn 0.2m[22m” causes a warning if [1mbreak  [22mwarn‐
              ings  are  not  suppressed  and [4mtroff[24m must add 0.2 m or more for
              each inter‐word space in a line.

       [1m.stringdown [4m[22mstr[0m
       [1m.stringup [4m[22mstr[0m
              Alter the string named [4mstr[24m by replacing each of its  bytes  with
              its  lowercase ([1mdown[22m) or uppercase ([1mup[22m) version (if one exists).
              Special characters (see [4mgroff_char[24m(7)) will often  transform  in
              the  expected  way  due to the regular naming convention for ac‐
              cented characters.  When they  do  not,  use  substrings  and/or
              catenation.

                     [1m.ds resume R\['e]sum\['e]\"[0m
                     [1m\*[resume][0m
                     [1m.stringdown resume[0m
                     [1m\*[resume][0m
                     [1m.stringup resume[0m
                     [1m\*[resume][0m
                     Résumé résumé RÉSUMÉ

       [1m.sty [4m[22mn[24m [4ms[0m
              Associate abstract style [4ms[24m with font mounting position [4mn[24m.

       [1m.substring [4m[22mstring[24m [4mstart[24m [[4mend[24m]
              Replace  the  string  named [4mstring[24m with its substring bounded by
              the indices [4mstart[24m and [4mend[24m, inclusively.  The first character  in
              the string has index 0.  If [4mend[24m is omitted, it is implicitly set
              to the largest valid value (the string length minus one).  Nega‐
              tive  indices  count  backwards  from the end of the string: the
              last character has index -1, the character before the  last  has
              index -2, and so on.

                     [1m.ds xxx abcdefgh[0m
                     [1m.substring xxx 1 -4[0m
                     [1m\*[xxx][0m
                     bcde
                     [1m.substring xxx 2[0m
                     [1m\*[xxx][0m
                     de

       [1m.tkf [4m[22mf[24m [4ms1[24m [4mn1[24m [4ms2[24m [4mn2[0m
              Enable track kerning for font [4mf[24m.  When the current font is [4mf[24m the
              width  of  every  glyph is increased by an amount between [4mn1[24m and
              [4mn2[24m; when the current type size is less than or equal to  [4ms1[24m  the
              width is increased by [4mn1[24m; when it is greater than or equal to [4ms2[0m
              the width is increased by [4mn2[24m; when the type size is greater than
              or  equal  to  [4ms1[24m  and  less than or equal to [4ms2[24m the increase in
              width is a linear function of the type size.

       [1m.tm1 [4m[22mmessage[0m
              As [1mtm [22mrequest, but strips a leading neutral  double  quote  from
              [4mmessage[24m to allow the embedding of leading spaces.

       [1m.tmc [4m[22mmessage[0m
              As [1mtm1 [22mrequest, but does not append a newline.

       [1m.trf [4m[22mfile[0m
              Transparently  output  the  contents of file [4mfile[24m.  Each line is
              output as if preceded by [1m\![22m; however, the lines are not  subject
              to  copy‐mode  interpretation.   If the file does not end with a
              newline, then a newline is added.  Unlike [1mcf[22m, [4mfile[24m  cannot  con‐
              tain characters that are invalid as input to GNU [4mtroff[24m.

              For example, you can define a macro [4mx[24m containing the contents of
              file [4mf[24m, using

                     .di x
                     .trf f
                     .di

       [1m.trin [4m[22mabcd[0m
              This  is  the same as the [1mtr [22mrequest except that the [1masciify [22mre‐
              quest uses the character code  (if  any)  before  the  character
              translation.  Example:

                     .trin ax
                     .di xxx
                     a
                     .br
                     .di
                     .xxx
                     .trin aa
                     .asciify xxx
                     .xxx

              The result is “x a”.  Using [1mtr[22m, the result would be “x x”.

       [1m.trnt [4m[22mabcd[0m
              This  is the same as the [1mtr [22mrequest except that the translations
              do not apply to text that is transparently throughput into a di‐
              version with [1m\![22m.  For example,

                     .tr ab
                     .di x
                     \!.tm a
                     .di
                     .x

              prints [1mb[22m; if [1mtrnt [22mis used instead of [1mtr [22mit prints [1ma[22m.

       [1m.troff [22mMake the [1mt [22mconditional expression evaluate  true  and  [1mn  [22mfalse.
              See [1mnroff[22m.

       [1m.unformat [4m[22mdiv[0m
              Unformat  the  diversion  [4mdiv[24m.  Unlike [1masciify[22m, [1munformat [22mhandles
              only tabs and spaces between words, the latter  usually  arising
              from spaces or newlines in the input.  Tabs are treated as input
              tokens,  and spaces become adjustable again.  The vertical sizes
              of lines are not preserved, but glyph  information  (font,  type
              size, space width, and so on) is retained.

       [1m.vpt [4m[22mn[24m If [4mn[24m is non‐zero or missing, enable vertical position traps (the
              default),  otherwise  disable them.  Vertical position traps are
              those set by the [1mch[22m, [1mwh[22m, and [1mdt [22mrequests.

       [1m.warn [22m[[4mn[24m]
              Select the categories, or “types”, of reported warnings.   [4mn[24m  is
              the  sum of the numeric codes associated with each warning cate‐
              gory that is to be enabled; all other categories  are  disabled.
              The  categories and their associated codes are listed in section
              “Warnings” of [4mtroff[24m(1).  For example,  “[1m.warn  0[22m”  disables  all
              warnings, and “[1m.warn 1[22m” disables all warnings except those about
              missing glyphs.  If no argument is given, all warning categories
              are enabled.

       [1m.warnscale [4m[22msi[0m
              Set  the  scaling unit used in warnings to [4msi[24m.  Valid values for
              [4msi[24m are [1mu[22m, [1mi [22m(the default), [1mc[22m, [1mp[22m, and [1mP[22m.

       [1m.while [4m[22mcond‐expr[24m [4manything[0m
              Evaluate the conditional expression  [4mcond‐expr[24m,  and  repeatedly
              execute  [4manything[24m  unless  and  until [4mcond‐expr[24m evaluates false.
              [4manything,[24m which is often a conditional block, is referred to  as
              the [1mwhile [22mrequest’s [4mbody.[0m

              [4mtroff[24m  treats the body of a [1mwhile [22mrequest similarly to that of a
              [1mde [22mrequest (albeit one not read in copy mode), but stores it un‐
              der an internal name and deletes it when the loop finishes.  The
              operation of a macro containing a [1mwhile [22mrequest can slow signif‐
              icantly if the [1mwhile [22mbody is large.  Each time the macro is exe‐
              cuted, the [1mwhile [22mbody is parsed and stored again.  An often bet‐
              ter solution—and one that is more  portable,  since  AT&T  [4mtroff[0m
              lacked  the [1mwhile [22mrequest—is to instead write a recursive macro.
              It will be parsed only once (unless you redefine it).   To  pre‐
              vent  infinite  loops, the default number of available recursion
              levels is 1,000 or somewhat  less  (because  things  other  than
              macro  calls  can  be on the input stack).  You can disable this
              protective measure, or raise the limit, by  setting  the  [1mslimit[0m
              register.  See section “Debugging” below.

              If  a  [1mwhile  [22mbody  begins with a conditional block, its closing
              brace must end an input line.

              The [1mbreak [22mand [1mcontinue [22mrequests alter a  [1mwhile  [22mloop’s  flow  of
              control.

       [1m.write [4m[22mstream[24m [4manything[0m
              Write  [4manything[24m  to  [4mstream[24m, which must previously have been the
              subject of an [1mopen [22mrequest, followed by a newline.  [4manything[24m  is
              read  in copy mode.  An initial neutral double quote in [4manything[0m
              is stripped to allow the embedding of leading spaces.

       [1m.writec [4m[22mstream[24m [4manything[0m
              As [1mwrite[22m, but without a trailing newline.

       [1m.writem [4m[22mstream[24m [4mname[0m
              Write the contents of the macro or string [4mname[24m to [4mstream[24m,  which
              must  previously have been the subject of an [1mopen [22mrequest.  [4mname[0m
              is read in copy mode.

   [1mExtended requests[0m
       [1m.cf [4m[22mfile[0m
              In a diversion, embed an object which, when reread,  will  cause
              the  contents  of  [4mfile[24m to be copied verbatim to the output.  In
              AT&T [4mtroff[24m, the contents of [4mfile[24m are immediately copied  to  the
              output  regardless  of  whether a diversion is being written to;
              this behavior is so anomalous that it must be considered a bug.

       [1m.de [4m[22mname[24m [[4mend‐name[24m]
       [1m.am [4m[22mname[24m [[4mend‐name[24m]
       [1m.ds [4m[22mname[24m [[4mcontents[24m]
       [1m.as [4m[22mname[24m [[4mcontents[24m]
              In compatibility mode, these requests behave similarly  to  [1mde1[22m,
              [1mam1[22m, [1mds1[22m, and [1mas1[22m, respectively: a “compatibility save” token is
              inserted  at  the beginning, and a “compatibility restore” token
              at the end, with compatibility mode switched  on  during  execu‐
              tion.

       [1m.hy [4m[22mn[24m  New  values  16 and 32 are available; the former enables hyphen‐
              ation before the last character in a word, and  the  latter  en‐
              ables hyphenation after the first character in a word.

       [1m.ss [4m[22mword‐space‐size[24m [[4madditional‐sentence‐space‐size[24m]
              A second argument sets the amount of additional space separating
              sentences  on  the same output line.  If omitted, this amount is
              set to [4mword‐space‐size[24m.  Both arguments are in twelfths of  cur‐
              rent  font’s  space  width (typically one‐fourth to one‐third em
              for Western scripts; see [4mgroff_font[24m(5)).  The default  for  both
              parameters is 12.  Negative values are erroneous.

       [1m.ta [22m[[[4mn1[24m [4mn2[24m ... [4mnn[24m ][1mT [4m[22mr1[24m [4mr2[24m ... [4mrn[24m]
              [4mgroff[24m supports an extended syntax to specify repeating tab stops
              after  the  “[1mT[22m” mark.  These values are always taken as relative
              distances from the previous tab stop.  This is the idiomatic way
              to specify tab stops at equal intervals in [4mgroff[24m.

              The syntax summary above instructs [4mgroff[24m to set  tabs  at  posi‐
              tions [4mn1[24m, [4mn2[24m, ..., [4mnn[24m, then at [4mnn[24m+[4mr1[24m, [4mnn[24m+[4mr2[24m, ..., [4mnn[24m+[4mrn[24m, then at
              [4mnn[24m+[4mrn[24m+[4mr1[24m, [4mnn[24m+[4mrn[24m+[4mr2[24m, ..., [4mnn[24m+[4mrn[24m+[4mrn[24m, and so on.

   [1mNew registers[0m
       GNU  [4mtroff[24m  exposes  more formatter state via many new read‐only regis‐
       ters.  Their names often correspond to the requests that affect them.

       [1m\n[.br]     [22mWithin a macro call, interpolate 1 if the macro  is  called
                   with the “normal” control character (“.” by default), and 0
                   otherwise.   This facility allows the reliable modification
                   of requests.  Using this register outside of a macro defin‐
                   ition makes no sense.

                          .als bp*orig bp
                          .de bp
                          .tm before bp
                          .ie \\n[.br] .bp*orig
                          .el 'bp*orig
                          .tm after bp
                          ..

       [1m\n[.C]      [22mInterpolate 1 if compatibility mode is in effect, 0  other‐
                   wise.  See [1mcp[22m.

       [1m\n[.cdp]    [22mInterpolate  depth  of last glyph added to the environment.
                   It is positive if the glyph extends below the baseline.

       [1m\n[.ce]     [22mInterpolate number of input lines remaining to be centered.

       [1m\n[.cht]    [22mInterpolate height of last glyph added to the  environment.
                   It is positive if the glyph extends above the baseline.

       [1m\n[.color]  [22mInterpolate 1 if colors are enabled, 0 otherwise.

       [1m\n[.cp]     [22mWithin  a “[1mdo[22m” request, interpolate the saved value of com‐
                   patibility mode (see [1m\n[.C] [22mabove).

       [1m\n[.csk]    [22mInterpolate skew of last glyph added  to  the  environment.
                   The  [4mskew[24m  of a glyph is how far to the right of the center
                   of a glyph the center of an accent over that  glyph  should
                   be placed.

       [1m\n[.ev]     [22mInterpolate name of current environment.  This is a string‐
                   valued register.

       [1m\n[.fam]    [22mInterpolate name of default font family.  This is a string‐
                   valued register.

       [1m\n[.fn]     [22mInterpolate  resolved name of the selected font.  This is a
                   string‐valued register.

       [1m\n[.fp]     [22mInterpolate next free font mounting position.

       [1m\n[.g]      [22mInterpolate 1.  Test with “[1mif[22m” or [1mie [22mto check  whether  GNU
                   [4mtroff[24m is the formatter.

       [1m\n[.height] [22mInterpolate font height.  See [1m\H[22m.

       [1m\n[.hla]    [22mInterpolate  hyphenation language of the environment.  This
                   is a string‐valued register.

       [1m\n[.hlc]    [22mInterpolate count of immediately preceding consecutive  hy‐
                   phenated lines in the environment.

       [1m\n[.hlm]    [22mInterpolate  maximum number of consecutive hyphenated lines
                   allowed in the environment.

       [1m\n[.hy]     [22mInterpolate hyphenation mode of the environment.

       [1m\n[.hym]    [22mInteprolate hyphenation margin of the environment.

       [1m\n[.hys]    [22mInterpolate hyphenation space adjustment threshold  of  the
                   environment.

       [1m\n[.in]     [22mInterpolate  indentation  amount  applicable to the pending
                   output line.

       [1m\n[.int]    [22mInterpolate 1 if the previous output line  was  interrupted
                   (ended with [1m\c[22m), 0 otherwise.

       [1m\n[.kern]   [22mInterpolate 1 if pairwise kerning is enabled, 0 otherwise.

       [1m\n[.lg]     [22mInterpolate ligature mode.

       [1m\n[.linetabs][0m
                   Interpolate 1 if line‐tabs mode is enabled, 0 otherwise.

       [1m\n[.ll]     [22mInterpolate  line  length  applicable to the pending output
                   line.

       [1m\n[.lt]     [22mInterpolate title line length.

       [1m\n[.m]      [22mInterpolate name of the selected stroke color.  This  is  a
                   string‐valued register.

       [1m\n[.M]      [22mInterpolate  name  of  the  selected fill color.  This is a
                   string‐valued register.

       [1m\n[.ne]     [22mInterpolate amount of space demanded by the most recent  [1mne[0m
                   request that caused a page location trap to be sprung.  See
                   [1m\n[.trunc][22m.

       [1m\n[.nm]     [22mInterpolate  1 if output line numbering is enabled (even if
                   temporarily suppressed), 0 otherwise.

       [1m\n[.ns]     [22mInterpolate 1 if no‐space mode is enabled, 0 otherwise.

       [1m\n[.O]      [22mInterpolate output suppression level.  See [1m\O[22m.

       [1m\n[.P]      [22mInterpolate 1 if the current page is selected  for  output.
                   See [1m-o [22mcommand‐line option to [4mtroff[24m(1).

       [1m\n[.pe]     [22mInterpolate 1 during page ejection, 0 otherwise.

       [1m\n[.pn]     [22mInterpolate  next  page  number  (either that set by [1mpn[22m, or
                   that of the current page plus 1).

       [1m\n[.ps]     [22mInterpolate type size in scaled points.

       [1m\n[.psr]    [22mInterpolate most recently requested  type  size  in  scaled
                   points.

       [1m\n[.pvs]    [22mInterpolate post‐vertical line spacing amount.

       [1m\n[.rj]     [22mInterpolate  number  of  input lines remaining to be right‐
                   aligned.

       [1m\n[.slant]  [22mInterpolate font slant.  See [1m\S[22m.

       [1m\n[.sr]     [22mInterpolate most recently requested type size in points  as
                   a decimal fraction.  This is a string‐valued register.

       [1m\n[.ss][0m
       [1m\n[.sss]    [22mInterpolate  values  of  minimal inter‐word space and addi‐
                   tional inter‐sentence space, respectively, in  twelfths  of
                   the space width of the selected font.

       [1m\n[.sty]    [22mInterpolate  selected abstract font style, if any.  This is
                   a string‐valued register.

       [1m\n[.tabs]   [22mInterpolate representation of the tab stop  settings  in  a
                   form suitable for passage to the [1mta [22mrequest.

       [1m\n[.trunc]  [22mInterpolate  amount of vertical space truncated by the most
                   recently sprung page location trap, or,  if  the  trap  was
                   sprung  by  an [1mne [22mrequest, minus the amount of vertical mo‐
                   tion produced by the [1mne [22mrequest.  In other  words,  at  the
                   point  a  trap is sprung, [1m\n[.trunc] [22mrepresents the differ‐
                   ence of what the vertical position would have been but  for
                   the  trap, and what the vertical position actually is.  See
                   [1m\n[.ne][22m.

       [1m\n[.U]      [22mInterpolate 1 if in unsafe mode, 0 otherwise.  See [1m-U  [22mcom‐
                   mand‐line option to [4mtroff[24m(1).

       [1m\n[.vpt]    [22mInterpolate  1  if  vertical  position  traps  are enabled,
                   0 otherwise.

       [1m\n[.warn]   [22mInterpolate  warning  mode.   See  section  “Warnings”   of
                   [4mtroff[24m(1).

       [1m\n[.x]      [22mInterpolate  major version number of the running [4mtroff[24m for‐
                   matter.  For example, if the version number is 1.23.0, then
                   [1m\n[.x] [22mcontains 1.

       [1m\n[.y]      [22mInterpolate minor version number of the running [4mtroff[24m  for‐
                   matter.  For example, if the version number is 1.23.0, then
                   [1m\n[.y] [22mcontains 23.

       [1m\n[.Y]      [22mInterpolate revision number of the running [4mtroff[24m formatter.
                   For  example,  if the version number is 1.23.0, then [1m\n[.Y][0m
                   contains 0.

       [1m\n[.zoom]   [22mInterpolate magnification of font, in thousandths, or 0  if
                   magnification unused.  See [1mfzoom[22m.

       The following (writable) registers are set by the [1mpsbb [22mrequest.

       [1m\n[llx][0m
       [1m\n[lly][0m
       [1m\n[urx][0m
       [1m\n[ury][0m
              Interpolate  the (upper, lower, left, right) bounding box values
              (in PostScript units) of the most recently processed  PostScript
              image.

       The following (writable) registers are set by the [1m\w [22mescape sequence.

       [1m\n[rst][0m
       [1m\n[rsb] [22mLike  [1m\n[st]  [22mand [1m\n[sb][22m, but taking account of the heights and
               depths of glyphs.  In other words, these  registers  store  the
               highest  and lowest vertical positions attained by the argument
               formatted by the [1m\w [22mescape sequence, doing what AT&T [4mtroff[24m doc‐
               umented [1m\n[st] [22mand [1m\n[sb] [22mas doing.

       [1m\n[ssc] [22mThe amount of horizontal space (possibly negative) that  should
               be added to the last glyph before a subscript.

       [1m\n[skw] [22mHow  far to right of the center of the last glyph in the [1m\w [22mar‐
               gument, the center of an accent from a  roman  font  should  be
               placed over that glyph.

       Other  writable  registers  are as follows.  Those relating to date and
       time are initialized using [4mlocaltime[24m(3) at formatter startup.

       [1m\n[c.]      [22mInterpolate input line number.  [1m\n[.c] [22mis a read‐only alias
                   of this register.

       [1m\n[hours]   [22mInterpolate number of hours elapsed since midnight.

       [1m\n[hp]      [22mInterpolate horizontal position relative  to  that  at  the
                   start of the input line.

       [1m\n[lsn][0m
       [1m\n[lss]     [22mInterpolate  count  of  leading  spaces  on  input line and
                   amount of corresponding horizontal motion, respectively.

       [1m\n[minutes] [22mInterpolate number of minutes elapsed in the hour.

       [1m\n[seconds] [22mInterpolate number of seconds elapsed in the minute.

       [1m\n[systat]  [22mInterpolate return value of [4msystem[24m(3) function executed  by
                   most recent [1msy [22mrequest.

       [1m\n[slimit]  [22mInterpolates  maximum quantity of objects on [4mtroff[24m’s inter‐
                   nal input stack (default: 1000).  If non‐positive, there is
                   no limit: recursion can continue until  program  memory  is
                   exhausted.

       [1m\n[year]    [22mInterpolate  Gregorian  year.   AT&T [4mtroff[24m’s [1m\[yr] [22minterpo‐
                   lates the Gregorian year minus 1900.

   [1mMiscellaneous[0m
       GNU [4mtroff[24m predefines one string, [1m.T[22m, containing the argument  given  to
       the  [1m-T [22mcommand‐line option, namely the output device (for example, [1mpdf[0m
       or [1mutf8[22m).  The (read‐only) [4mregister[24m [1m.T [22minterpolates 1 if GNU  [4mtroff[24m  is
       run with the [1m-T [22mcommand‐line option, and 0 otherwise.

       A font not listed in the output device’s [4mDESC[24m file’s [1mfonts [22mdirective is
       automatically  mounted  at  the next available font position when it is
       selected.  If you mount a font explicitly  with  the  [1mfp  [22mrequest,  you
       should  do  so  on the first unused position, which can be found in the
       [1m.fp [22mregister.

       Unparameterized string interpolation does not conceal the arguments  to
       a  macro  being  interpreted.  Thus, in a macro definition, the call of
       another macro with the existing argument list,
              [1m.[4m[22mxx[24m [1m\\$@[0m
       is more efficiently done with
              [1m\\*[[4m[22mxx[24m[1m]\\[0m
       (that is, with string interpolation).  The trailing backslashes prevent
       the final newline in the macro definition from being interpolated,  po‐
       tentially  putting  an  unwanted blank line on the output.  See section
       “Punning Names” in [4mgroff[24m(7).

       If a font  description  file  contains  pairwise  kerning  information,
       glyphs  from  that  font are kerned.  Kerning between two glyphs can be
       inhibited by placing a dummy character [1m\& [22mbetween them.

       GNU [4mtroff[24m keeps track of the nesting depth of escape sequence  interpo‐
       lations and other uses of delimiters, as in the [1mtl [22mrequest and the out‐
       put comparison operator (that is, input like [1m'foo'bar' [22mas a conditional
       expression),  so  the only characters you need to avoid using as delim‐
       iters are those that appear in the arguments you input,  not  any  that
       result from interpolation.  Typically, [1m' [22mworks fine.  Use visible char‐
       acters  as delimiters in GNU [4mtroff[24m, not “ASCII” controls like BEL (Con‐
       trol+G).  The implementation of [1m\$@ [22mensures that the double quotes sur‐
       rounding an argument appear at an interpolation  depth  different  from
       that  of  the  arguments themselves.  Similarly, in bracket‐form escape
       sequences like [1m\f[ZCMI], [22ma right bracket [1m] [22mdoes not  end  the  sequence
       unless  it  occurs at the same interpolation depth as the opening [1m[[22m, so
       input like
              \f[\*[my‐family]\*[my‐style]]
       works as desired.  In compatibility mode, no attention is paid  to  the
       interpolation depth.

       In  GNU  [4mtroff[24m,  the  [1mtr  [22mrequest can map characters to the unbreakable
       space escape sequence [1m\~ [22mas a special case ([1mtr [22mnormally  operates  only
       on  [4mcharacters[24m).  This feature replaces the odd‐parity [1mtr [22mmapping trick
       used in AT&T [4mtroff[24m documents, where a character, often [1m~[22m,  was  “sacri‐
       ficed”  by  mapping  it  to “nothing”, drafting it into use as an unad‐
       justable, unbreakable space.  (This  feature  was  gratuitous  even  in
       early  AT&T [4mtroff,[24m which supported the [1m\[4m[22mspace[24m escape sequence by 1976.)
       Often, it makes more sense to use GNU [4mtroff[24m’s [1m\~  [22mescape  sequence  in‐
       stead,  which  has been adopted by every other active [4mtroff[24m implementa‐
       tion except that of Illumos,  as  well  as  by  the  non[4m‐troff[24m  [4mmandoc[24m.
       Translation of a character to [1m\~ [22mis unnecessary.

       GNU [4mtroff[24m permits tabs and spaces after the first dot on a control line
       that ends a macro definition.
              .if t \{\
              .  de bar
              .    nop Hello, I'm 'bar'.
              .  .
              .\}

[1mFormatter output[0m
       The page description language output by GNU [4mtroff[24m is modeled after that
       used  by  AT&T  [4mtroff[24m  once the latter adopted a device‐independent ap‐
       proach in the early 1980s.  Only the differences are  documented  here.
       For a fuller discussion, see [4mgroff_out[24m(5).

       Glyph  and font names can be of arbitrary length; postprocessors should
       not assume that they are at most two characters.  A glyph to be format‐
       ted is always drawn from the current font; in contrast to AT&T  device‐
       independent  [4mtroff[24m,  drivers  need  not  search special fonts to find a
       glyph.

   [1mUnits[0m
       The argument to the [1ms [22mcommand is in scaled points (units  of  points/[4mn[24m,
       where  [4mn[24m  is  the  argument to the [1msizescale [22mcommand in the [4mDESC[24m file).
       The argument to the “[1mx H[22m” command is also in scaled points.

   [1mSimple commands[0m
       If the [1mtcommand [22mdirective is present in the output device’s [4mDESC[24m  file,
       GNU [4mtroff[24m employs the following two commands.

       [1mt [4m[22mxyz[24m...
              Typeset  word  [4mxyz[24m;  that  is, set a sequence of ordinary glyphs
              named [4mx[24m, [4my[24m, [4mz[24m, ..., terminated by a space  or  newline;  an  op‐
              tional  second integer argument is ignored (this allows the for‐
              matter to generate an even number of arguments).  Each glyph  is
              set  at  the  current drawing position, and the position is then
              advanced horizontally by the glyph’s width.  A glyph’s width  is
              read  from  its  metrics in the font description file, scaled to
              the current type size, and rounded to a multiple of the horizon‐
              tal motion quantum.  Use the [1mC [22mcommand to emplace glyphs of spe‐
              cial characters.

       [1mu [4m[22mn[24m [4mxyz[24m...
              Typeset word [4mxyz[24m with track kerning.  As [1mt[22m,  but  after  placing
              each  glyph,  the  drawing position is further advanced horizon‐
              tally by [4mn[24m basic units.

       New commands implement color support.

       [1mmc [4m[22mcyan[24m [4mmagenta[24m [4myellow[0m
       [1mmd[0m
       [1mmg [4m[22mgray[0m
       [1mmk [4m[22mcyan[24m [4mmagenta[24m [4myellow[24m [4mblack[0m
       [1mmr [4m[22mred[24m [4mgreen[24m [4mblue[0m
              Set the components of the stroke color with respect  to  various
              color  spaces.  [1mmd [22mresets the stroke color to the default value.
              The arguments are integers in the range 0 to 65535.

       A new device control subcommand is available.

       [1mx u [4m[22mn[24m  If [4mn[24m is 1, start underlining of spaces.  If [4mn[24m is 0, stop  under‐
              lining of spaces.  This facility is needed for the [1mcu [22mrequest in
              [4mnroff[24m mode and is ignored otherwise.

   [1mExtended drawing commands[0m
       GNU  [4mpic[24m does not produce [4mtroff[24m escape sequences employing these exten‐
       sions if its [1m-n [22moption is given.

       [1mDf [4m[22mn[24m   Set the shade of gray used to fill geometric objects to [4mn[24m, which
              must be an integer.  0 corresponds to white and 1000  to  black.
              A grayscale ramp spans the two.  A value outside this range uses
              the  stroke  color as the fill color.  The fill color is opaque.
              Normally the default is black, but some drivers  may  provide  a
              way  of changing this.  [1mDf [22mis obsolete since 2002, superseded by
              [1mDFg [22mbelow.

              The corresponding [1m\D'f' [22mescape sequence should not be used:  its
              argument is rounded to an integer multiple of the horizontal mo‐
              tion quantum, which can limit the precision of [4mn[24m.

       [1mDC [4m[22md[24m   Draw  a  filled  circle of diameter [4md[24m with its leftmost point at
              the drawing position.

       [1mDE [4m[22mh[24m [4mv[24m Draw a filled ellipse, of horizontal axis [4mh[24m and vertical axis [4mv[24m,
              with its leftmost point at the drawing position.

       [1mDp [4m[22mdx[24m1[4mdy[24m1...[4mdxndyn[0m
              Draw a polygon with, for [4mi[24m=1,...,[4mn[24m+1,  its  [4mi[24mth  vertex  at  the
              drawing  position +[4mij[24m−=Σ11([4mdxj[24m,[4mdyj[24m).  [4mgroff[24m output drivers automati‐
              cally close polygons, drawing a  line  from  ([4mdxn[24m,[4mdyn[24m)  back  to
              ([4mdx[24m1,[4mdy[24m1).   The  drawing position is left at the last [4mspecified[0m
              vertex, but this may change in a future version  of  GNU  [4mtroff[24m.
              Heirloom  Doctools  [4mtroff[24m,  like  DWB [4mtroff[24m, by default does not
              close the polygon.  In its [4mgroff[24m  compatibility  mode,  Heirloom
              closes  the  polygon  but leaves the drawing position [4munchanged[24m—
              that is, at the polygon’s [4minitial[24m drawing position.

              At the moment, GNU [4mpic[24m uses this command only to generate trian‐
              gles and rectangles.

       [1mDP [4m[22mdx[24m1[4mdy[24m1...[4mdxndyn[0m
              As [1mDp[22m, but draw a filled rather than a stroked polygon.

       [1mDt [4m[22mn[24m   Set the line thickness to [4mn[24m basic units.  AT&T [4mtroff[24m output dri‐
              vers use a thickness proportional to the type size; this is  the
              GNU [4mtroff[24m default.  A negative [4mn[24m requests this explicitly.  An [4mn[0m
              of zero selects the smallest available line thickness.

       A difficulty arises in how the drawing position should be changed after
       the  execution  of  these commands.  This has little importance to most
       users, since the output of GNU [4mgrn[24m and  [4mpic[24m  does  not  depend  on  it.
       Given a drawing command of the form [1mD[4m[22mz[24m [4mx[24m1[4my[24m1...[4mxnyn[24m, where [4mz[24m is not [1mc [22mor
       [1me[22m,  AT&T [4mtroff[24m treats each [4mxi[24m as a horizontal motion, each [4myi[24m as a ver‐
       tical one, and therefore assumes that the width of the drawn object  is
       [4min[24m=Σ1[4mxi[24m, and its height is [4min[24m=Σ1[4myi[24m.  (Verify its assumption about height by
       examining the [1mst [22mand [1msb [22mregisters after using such a drawing command in
       a  [1m\w  [22mescape sequence).  For the sake of compatibility, GNU [4mtroff[24m also
       follows this rule, even though it frustrates extensions to the  [1mD  [22mcom‐
       mand that set drawing parameters rather than rendering objects, produc‐
       ing  ugly  results in the case of [1mDt [22mand [1mDf[22m, or otherwise don’t parame‐
       terize objects as a series of vertices, as with GNU [4mtroff[24m’s filled  el‐
       lipse,   [1mDE[22m.   Thus  after  executing  a  [1mD  [22mcommand  of  the  form  [1mD[4m[22mz[0m
       [4mx[24m1[4my[24m1...[4mxnyn[24m, the drawing position should be increased by ([4min[24m=Σ1[4mxi[24m,[4min[24m=Σ1[4myi[24m).
       In a future release, GNU [4mtroff[24m and its output drivers may  abandon  the
       application of this assumption to drawing commands not explicitly spec‐
       ified in the AT&T “Troff User’s Manual”.

       Fill color selection is implemented with another set of extensions.

       [1mDFc [4m[22mcyan[24m [4mmagenta[24m [4myellow[0m
       [1mDFd[0m
       [1mDFg [4m[22mgray[0m
       [1mDFk [4m[22mcyan[24m [4mmagenta[24m [4myellow[24m [4mblack[0m
       [1mDFr [4m[22mred[24m [4mgreen[24m [4mblue[0m
              Set  the  components of the fill color as described under the [1m\M[0m
              escape sequence above.  [1mDFd [22mrestores the device’s  default  fill
              color.  The drawing position is not updated, in contrast to [1mDf[22m.

   [1mDevice control syntax extension[0m
       GNU [4mtroff[24m introduces a line continuation convention, permitting the ar‐
       gument  to the [1mx X [22mcommand to contain newlines.  A newline in the input
       is transformed to the sequence “[4mnewline[24m[1m+[22m”.  When interpreting  an  [1mx  X[0m
       command,  a  postprocessor should therefore be prepared for a plus sign
       after a newline; if it occurs, preserve the newline, discard  the  plus
       sign,  and  continue  to collect the input into the argument of the [1mx X[0m
       command.  A newline [4mnot[24m followed by a plus sign terminates the [1mx X [22mcom‐
       mand.  An application of this feature is the embedding of PostScript or
       PDF language command streams into [4mtroff[24m output.

       GNU [4mtroff[24m guarantees that the first three output commands it emits  are
       as follows.

              x T [4mdevice[0m
              x res [4mn[24m [4mh[24m [4mv[0m
              x init

[1mDebugging[0m
       In  addition  to  AT&T [4mtroff[24m’s debugging features, GNU [4mtroff[24m emits more
       error diagnostics when syntactical or semantic nonsense is  encountered
       and supports several warning categories; the output of these can be se‐
       lected  with  [1mwarn[22m.   Also  see the [1m-E[22m, [1m-w[22m, and [1m-W [22moptions of [4mtroff[24m(1).
       Backtraces can be automatically produced when errors or warnings  occur
       (the [1m-b [22moption of [4mtroff[24m(1)) or generated on demand ([1mbacktrace[22m).

       [4mgroff[24m also adds more flexible diagnostic output requests ([1mtmc [22mand [1mtm1[22m).
       More  aspects  of  formatter  state  can be examined with requests that
       write lists of defined registers ([1mpnr[22m), environments  ([1mpev[22m),  and  page
       location traps ([1mptr[22m) to the standard error stream.

[1mImplementation differences[0m
       GNU  [4mtroff[24m’s  features sometimes cause incompatibilities with documents
       written assuming old implementations of [4mtroff[24m.  Some GNU extensions  to
       [4mtroff[24m are supported by other implementations.

       When  adjusting  to  both  margins,  AT&T [4mtroff[24m at first adjusts spaces
       starting from the right; GNU [4mtroff[24m begins from the left.   Both  imple‐
       mentations adjust spaces from opposite ends on alternating output lines
       to prevent “rivers” in the text.

       GNU [4mtroff[24m does not always hyphenate words as AT&T [4mtroff[24m does.  The AT&T
       implementation uses a set of hard‐coded rules specific to U.S. English,
       while  GNU  [4mtroff[24m  uses language‐specific hyphenation pattern files de‐
       rived from TeX.  In some versions of [4mtroff[24m there was limited  space  to
       store  hyphenation  exceptions (arguments to the [1mhw [22mrequest); GNU [4mtroff[0m
       has no such restriction.

       Long names may be GNU [4mtroff[24m’s most obvious innovation.  AT&T [4mtroff[24m  in‐
       terprets  “[1m.dsabcd[22m” as defining a string “[1mab[22m” with contents “[1mcd[22m”.  Nor‐
       mally, GNU [4mtroff[24m interprets this as a call of a macro  named  “[1mdsabcd[22m”.
       AT&T  [4mtroff[24m also interprets [1m\*[ [22mand [1m\n[ [22mas an interpolation of a string
       or register, respectively, called “[1m[[22m”.  In GNU [4mtroff[24m, however, the  “[1m[[22m”
       is  normally  interpreted  as beginning the enclosure of a long identi‐
       fier.  In compatibility mode, GNU [4mtroff[24m interprets names in the  tradi‐
       tional way, which means that they are limited to one or two characters.
       See the [1m-C [22moption in [4mtroff[24m(1) and, above, the [1m.C [22mand [1m.cp [22mregisters, and
       [1mcp [22mand “[1mdo[22m” requests, for more on compatibility mode.

       The  register [1m\n[.cp] [22mis specialized and may require a statement of ra‐
       tionale.  When writing macro packages or documents that use  GNU  [4mtroff[0m
       features  and  which may be mixed with other packages or documents that
       do not—common scenarios include serial processing of man pages  or  use
       of the “[1mso[22m” or [1mmso [22mrequests—you may desire correct operation regardless
       of  compatibility  mode  enablement in the surrounding context.  It may
       occur to you to save the existing value of [1m\n(.C [22minto a register,  say,
       [1m_C[22m,  at  the  beginning  of your file, turn compatibility mode off with
       “[1m.cp  0[22m”,  then  restore  it  from  that  register  at  the  end   with
       “[1m.cp \n(_C[22m”.  At the same time, a modular design of a document or macro
       package  may  lead you to multiple layers of inclusion.  You cannot use
       the same register name everywhere lest you “clobber” the value  from  a
       preceding  or enclosing context.  The two‐character register name space
       of AT&T [4mtroff[24m is confining and mnemonically challenging; you  may  wish
       to use GNU [4mtroff[24m’s more capacious name space.  However, attempting “[1m.nr[0m
       [1m_my_saved_C  \n(.C[22m”  will  not work in compatibility mode; the register
       name is too long.  “This is exactly what [1m.do [22mis for,” you  think,  “[1m.do[0m
       [1mnr  _my_saved_C  \n(.C[22m”.   The  foregoing will always save zero to your
       register, because “[1mdo[22m” turns compatibility mode [4moff[24m while it interprets
       its argument list.  What you need is:
              .do nr _my_saved_C \n[.cp]
              .cp 0
       at the beginning of your file, followed by
              .cp \n[_my_saved_C]
              .do rr _my_saved_C
       at the end.  As in the C language, we all have to share  one  big  name
       space, so choose a register name that is unlikely to collide with other
       uses.

       The  existence  of  the  [1m.T [22mstring is a common feature of post‐CSTR #54
       [4mtroff[24ms—DWB 3.3, Solaris, Heirloom Doctools, and Plan 9 [4mtroff[24m  all  sup‐
       port  it—but valid values are specific to each implementation.  The be‐
       havior of the [1m.T [22mregister in GNU [4mtroff[24m differs from AT&T  [4mtroff[24m,  which
       interpolated 1 only if [4mnroff[24m was the formatter and was called with [1m-T[22m.

       The [1mlf [22mrequest sets the number of the [4mcurrent[24m input line in AT&T [4mtroff[24m,
       and the [4mnext[24m in GNU [4mtroff[24m.

       AT&T  [4mtroff[24m  had  only  environments  named  “[1m0[22m”, “[1m1[22m”, and “[1m2[22m”.  In GNU
       [4mtroff[24m, any number of environments may exist, using  any  valid  identi‐
       fiers for their names.

       GNU  [4mtroff[24m  normally  tracks the interpolation depth of escape sequence
       parameters and other delimited structures,  but  not  in  compatibility
       mode.  See section “Miscellaneous” above.

       In compatibility mode, the escape sequences [1m\f[22m, [1m\H[22m, [1m\m[22m, [1m\M[22m, [1m\R[22m, [1m\s[22m, and
       [1m\S [22mare transparent at the beginning of an input line for the purpose of
       recognizing  a  control  character, because they modify formatter state
       ([1m\R[22m) or properties of the environment (the rest) and therefore  do  not
       create  output  nodes.   For example, this code produces bold output in
       both cases, but the text differs,
              .de xx '
              Hello!
              ..
              \fB.xx\fP
       formatting “.xx” normally and “Hello!” in compatibility mode.

       GNU [4mtroff[24m request names unrecognized  by  other  [4mtroff[24m  implementations
       will  likely be ignored; escape sequences that are GNU [4mtroff[24m extensions
       are liable to format their function selector character.   For  example,
       the adjustable, non‐breaking space escape sequence [1m\~ [22mis also supported
       by  Heirloom  Doctools  [4mtroff[24m  050915  (September  2005),  [4mmandoc[24m 1.9.5
       (2009‐09‐21), [4mneatroff[24m (commit 1c6ab0f6e, 2016‐09‐13), and Plan 9  from
       User  Space  [4mtroff[24m  (commit  93f8143600,  2022‐08‐12),  but  not by So‐
       laris/Illumos [4mtroff[24ms, which will render it as [1m~[22m.

       GNU [4mtroff[24m does not allow the use of the escape sequences  [1m\|[22m,  [1m\^[22m,  [1m\&[22m,
       [1m\{[22m,  [1m\}[22m,  [1m\[4m[22mspace[24m,  [1m\'[22m,  [1m\`[22m,  [1m\-[22m, [1m\_[22m, [1m\![22m, [1m\%[22m, or [1m\c [22min identifiers; AT&T
       [4mtroff[24m does.  The [1m\A [22mescape sequence (see subsection “Escape  sequences”
       above) may be helpful in avoiding their use.

       Normally, the syntax form [1m\s[4m[22mn[24m accepts only a single character (a digit)
       for  [4mn[24m,  consistently  with  other forms that originated in AT&T [4mtroff[24m,
       like [1m\*[22m, [1m\$[22m, [1m\f[22m, [1m\g[22m, [1m\k[22m, [1m\n[22m, and [1m\z[22m.  In  compatibility  mode  only,  a
       non‐zero  [4mn[24m  must  be in the range 4–39.  Legacy documents relying upon
       this quirk of parsing should be migrated to another  [1m\s  [22mform.   [Back‐
       ground:  The Graphic Systems C/A/T phototypesetter (the original device
       target for AT&T [4mtroff[24m) supported only a few discrete type sizes in  the
       range 6–36 points, so Ossanna contrived a special case in the parser to
       do what the user must have meant.  Kernighan warned of this in the 1992
       revision  of CSTR #54 (§2.3), and more recently, McIlroy referred to it
       as a “living fossil”.]

       Fractional type sizes cause one noteworthy  incompatibility.   In  AT&T
       [4mtroff[24m  the [1mps [22mrequest ignores scaling units and thus “[1m.ps 10u[22m” sets the
       type size to 10 points, whereas in GNU [4mtroff[24m it sets the type  size  to
       10 [4mscaled[24m points, which may be a much smaller measurement.  See subsec‐
       tion “Fractional type sizes and new scaling units” above.

       The  [1mab [22mrequest differs from AT&T [4mtroff[24m: GNU [4mtroff[24m writes no message to
       the standard error stream if no arguments are given, and it exits  with
       a failure status instead of a successful one.

       The  [1mbp  [22mrequest  differs  from AT&T [4mtroff[24m: GNU [4mtroff[24m does not accept a
       scaling unit on the argument, a page number; the former (somewhat  use‐
       lessly) does.

       In AT&T [4mtroff[24m the [1mpm [22mrequest reports macro, string, and diversion sizes
       in  units  of  128‐byte blocks, and an argument reduces the report to a
       sum of the above in the same units.  GNU [4mtroff[24m  ignores  any  arguments
       and reports the sizes in bytes.

       Unlike AT&T [4mtroff[24m, GNU [4mtroff[24m does not ignore the [1mss [22mrequest if the out‐
       put is a terminal device; instead, the values of minimum inter‐word and
       additional  inter‐sentence  space  are each rounded down to the nearest
       multiple of 12.

       In GNU [4mtroff[24m there is a fundamental  difference  between  (unformatted)
       characters and (formatted) glyphs.  Everything that affects how a glyph
       is  output  is  stored  with the glyph node; once a glyph node has been
       constructed, it is unaffected by any subsequent requests that are  exe‐
       cuted, including [1mbd[22m, [1mcs[22m, [1mtkf[22m, [1mtr[22m, or [1mfp [22mrequests.  Normally, glyphs are
       constructed from characters immediately before the glyph is added to an
       output  line.   Macros,  diversions,  and strings are all, in fact, the
       same type of object; they contain a sequence  of  intermixed  character
       and  glyph  nodes.  Special characters transform from one to the other:
       before being added to the output, they behave as characters; afterward,
       they are glyphs.  A glyph node does not behave like  a  character  node
       when it is processed by a macro: it does not inherit any of the special
       properties  that the character from which it was constructed might have
       had.  For example, the input
              .di x
              \\\\
              .br
              .di
              .x
       produces “[1m\\[22m” in GNU [4mtroff[24m.  Each pair of backslashes becomes one back‐
       slash [4mglyph;[24m the resulting backslashes are thus not interpreted as  es‐
       cape  [4mcharacters[24m when they are reread as the diversion is output.  AT&T
       [4mtroff[24m [4mwould[24m interpret them as escape characters when rereading them and
       end up printing one “[1m\[22m”.

       One way to format a backslash in most documents is with the  [1m\e  [22mescape
       sequence;  this  formats the glyph of the current escape character, re‐
       gardless of whether it is used in a diversion; it also  works  in  both
       GNU  [4mtroff[24m  and  AT&T  [4mtroff[24m.  (Naturally, if you’ve changed the escape
       character, you need to prefix the “[1me[22m” with whatever  it  is—and  you’ll
       likely get something other than a backslash in the output.)

       The other correct way, appropriate in contexts independent of the back‐
       slash’s  common use as a [4mroff[24m escape character—perhaps in discussion of
       character sets or other programming languages—is the  character  escape
       [1m\(rs  [22mor  [1m\[rs][22m,  for  “reverse  solidus”,  from its name in the ECMA‐6
       (ISO/IEC 646) standard.  [This escape sequence is not portable to  AT&T
       [4mtroff[24m,  but is to its lineal descendant, Heirloom Doctools [4mtroff[24m, as of
       its 060716 release (July 2006).]

       To store an escape sequence in a diversion that is interpreted when the
       diversion is reread, either use the traditional [1m\!  [22mtransparent  output
       facility,  or,  if this is unsuitable, the new [1m\? [22mescape sequence.  See
       subsection “Escape  sequences”  above  and  sections  “Diversions”  and
       “gtroff Internals” in [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, the [4mgroff[0m
       Texinfo manual.

       In the somewhat pathological case where a diversion exists containing a
       partially  collected  line  and  a partially collected line at the top‐
       level diversion has never existed, AT&T [4mtroff[24m will output the partially
       collected line at the end of input; GNU [4mtroff[24m will not.

   [1mFormatter output incompatibilities[0m
       Its extensions notwithstanding, the [4mgroff[24m  intermediate  output  format
       has some incompatibilities with that of AT&T [4mtroff[24m, but better compati‐
       bility is sought; problem reports and patches are welcome.  The follow‐
       ing incompatibilities are known.

       • The  drawing  position  after rendering polygons is inconsistent with
         AT&T [4mtroff[24m practice.  Other implementations  have  diverged  on  this
         point as well.

       • The output cannot be easily rescaled to other devices as AT&T [4mtroff[24m’s
         could.

[1mAuthors[0m
       This  document was written by James Clark ⟨jjc@jclark.com⟩, Werner Lem‐
       berg ⟨wl@gnu.org⟩, Bernd Warken ⟨groff-bernd.warken-72@web.de⟩, and  G.
       Branden Robinson ⟨g.branden.robinson@gmail.com⟩.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       “Troff  User’s  Manual” by Joseph F. Ossanna, 1976 (revised by Brian W.
       Kernighan, 1992), AT&T Bell Laboratories  Computing  Science  Technical
       Report No. 54, widely called simply “CSTR #54”, documents the language,
       device and font description file formats, and output format referred to
       collectively in [4mgroff[24m documentation as AT&T [4mtroff[24m.

       “A Typesetter‐independent TROFF” by Brian W. Kernighan, 1982, AT&T Bell
       Laboratories  Computing Science Technical Report No. 97, provides addi‐
       tional insights into the device and font description file  formats  and
       output format.

       [4mgroff[24m(1), [4mgroff[24m(7), [4mroff[24m(7)

groff 1.23.0                      5 July 2023                    [4mgroff_diff[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_hdtbl[24m(7)         Miscellaneous Information Manual         [4mgroff_hdtbl[24m(7)

[1mName[0m
       groff_hdtbl - Heidelberger table macros for GNU [4mroff[0m

[1mDescription[0m
       The  [4mhdtbl[24m  macros consist of four base and three optional macros, con‐
       trolled by about twenty arguments.  The syntax is simple and similar to
       the HTML table model and nearly as flexible: you can write sequences of
       tokens (macro calls with their arguments and content  data),  separated
       by  blanks  and  beginning with a macro call, into the same line to get
       compact and cleanly arrranged input.  An advantage of [4mhdtbl[24m is that the
       tables are constructed without calling a preprocessor; this means  that
       [4mgroff[24m(7)’s  full  macro capabilities are available.  On the other hand,
       table processing with [4mhdtbl[24m is much slower than using the  [4mtbl[24m(1)  pre‐
       processor.   A  further advantage is that the HTML‐like syntax of [4mhdtbl[0m
       will be easily converted to HTML; this is not implemented yet.

[1mUsage[0m
       In this and the next section, we present examples to help users  under‐
       stand  the  basic  workflow  of [4mhdtbl[24m.  First of all, you must load the
       [4mhdtbl.tmac[24m file.  As with nearly all other [4mgroff[24m macro packages,  there
       are two possibilities to do so: Either add the line

              .mso hdtbl.tmac

       to  your [4mroff[24m file before using any macros of the [4mhdtbl[24m package, or add
       the option

              -m hdtbl

       to the command line of groff (before the document file  which  contains
       [4mhdtbl[24m  macros).   Then  you can include on or more tables in your docu‐
       ment, where each one must be started and ended with the .TBL  and  .ETB
       macros, respectively.

       In this man page, we approximate the result of each example as terminal
       output to be as generic as possible since [4mhdtbl[24m currently only supports
       the [1mps [22mand [1mpdf [22moutput drivers.

       The  simplest  well‐formed  table  consists of just single calls to the
       four base table macros in the right order.  Here we construct  a  table
       with only one cell.

              .TBL
              .TR
              .TD
              [4mcontents[24m [4mof[24m [4mthe[24m [4mtable[24m [4mcell[0m
              .ETB

       A terminal representation is

              +------------------------------------------------------+
              | [4mcontents-of-the-table-cell[24m                           |
              +------------------------------------------------------+

       Equivalent to the above is the following notation.

              .TBL .TR .TD "[4mcontents[24m [4mof[24m [4mthe[24m [4mtable[24m [4mcell[24m" .ETB

       By  default,  the formatted table is inserted into the surrounding text
       at the place of its definition.  If the  vertical  space  isn’t  suffi‐
       cient,  it  is  placed at the top of the next page.  Tables can also be
       stored for later insertion.

       Using ‘[4mrow‐number[24m*[4mcolumn‐number[24m’ as the data for the table cells, a ta‐
       ble with two rows and two columns can be written as

              .TBL cols=2
              .  TR .TD 1*1 .TD 1*2
              .  TR .TD 2*1 .TD 2*2
              .ETB

       A terminal representation is

              +--------------------------+---------------------------+
              | 1*1                      | 1*2                       |
              +--------------------------+---------------------------+
              | 2*1                      | 2*2                       |
              +--------------------------+---------------------------+

       Here we see a difference from HTML tables: The number of  columns  must
       be  explicitly specified using the ‘cols=[4mm[24m’ argument (or indirectly via
       the ‘width’ argument, see below).

       The contents of a table cell is arbitrary; for example, it can  be  an‐
       other  table,  without restriction to the nesting depth.  A given table
       layout can be either constructed with suitably nested  tables  or  with
       proper  arguments  to .TD and .TH, controlling column and row spanning.
       Note, however, that this table

              .TBL
              .  TR
              .    TD
              .      nop 1*1 1*2
              .  TR
              .    TD
              .      TBL cols=2 border=
              .        TR
              .          TD
              .            nop 2*1
              .          TD
              .            nop 2*2
              .      ETB
              .ETB

       and this table

              .TBL cols=2
              .  TR
              .    TD colspan=2
              .      nop 1*1 1*2
              .  TR
              .    TD
              .      nop 2*1
              .    TD
              .      nop 2*2
              .ETB

       are similar but not identical (the use of .nop is  purely  cosmetic  to
       get proper indentation).

       The first table looks like

              +------------------------------------------------------+
              | 1*1 1*2                                              |
              +------------------------------------------------------+
              |                                                      |
              | 2*1                         2*2                      |
              |                                                      |
              +------------------------------------------------------+

       and the second one like

              +------------------------------------------------------+
              | 1*1 1*2                                              |
              +---------------------------+--------------------------+
              | 2*1                       | 2*2                      |
              +---------------------------+--------------------------+

       Here is the latter table in a more compact form.

              .TBL cols=2 .TR ".TD colspan=2" 1*1 1*2
              .            TR .TD 2*1 .TD 2*2 .ETB

       If  a macro has one or more arguments (see below), and it is not start‐
       ing a line, everything belonging to this macro including the macro  it‐
       self must be enclosed in double quotes.

[1mMacros and arguments[0m
       The  order  of macro calls and other tokens follows the HTML model.  In
       the following list, valid predecessors  and  successors  of  all  [4mhdtbl[0m
       macros are given, together with the possible arguments.

       Macro arguments are separated by blanks.  The order of arguments is ar‐
       bitrary; they are of the form

              key=[4mvalue[0m

       or

              key='[4mvalue1[24m [[4mvalue2[24m [...]]'

       with  the  only  exception  of the optional argument of the macro .ETB,
       which is the string ‘hold’.  Another possible form is

              "key=[4mvalue1[24m [[4mvalue2[24m [...]]"

       However, this is limited to the case where the macro is the  first  one
       in the line and not already enclosed in double quotes.

       Argument  values specified below as [4mc[24m are colors predefined by [4mgroff[24m or
       colors defined by the user with the .defcolor request.   Argument  val‐
       ues [4md[24m are decimal numbers with or without decimal point.  Argument val‐
       ues [4mm[24m are natural numbers.  Argument values [4mn[24m are numerical values with
       the usual [4mgroff[24m scaling indicators.  Some of the arguments are specific
       to one or two macros, but most of them can be specified with .TBL, .TR,
       .TD, and .TH.  These common arguments are explained in the next subsec‐
       tion.

       Most  of the argument default values can be changed by the user by set‐
       ting corresponding default registers or strings, as listed below.

       [1m.TBL [22m[[4margs[24m]
              Begin a new table.

              [1mpredecessor: [22m.TD, .TH, .ETB, cell contents
              [1msuccessor: [22m.CPTN, .TR
              [1marguments:[0m
                     border=[[4mn[24m]
                            Thickness   of   the   surrounding   box   border.
                            ‘border=’  (no  value) means neither a surrounding
                            box border nor any horizontal or vertical  separa‐
                            tor  lines  between  the  table  rows  and  cells.
                            ‘border=0’ suppresses the surrounding box  border,
                            but still allows separator lines between cells and
                            rows.
                            [1mDefault: [22m‘border=.1n’ (register ‘t*b’).
                     bc=[4mc[24m   Border color.
                            [1mDefault: [22m‘bc=red4’ (string ‘t*bc’).
                     cols=[4mm[24m Number  of table columns.  This argument is neces‐
                            sary if more than one column is in the  table  and
                            no ‘width’ arguments are present.
                            [1mDefault: [22m‘cols=1’ (register ‘t*cols’).
                     cpd=[4mn[24m  Cell  padding,  i.e.,  the extra space between the
                            cell space border and the cell contents.
                            [1mDefault: [22m‘cpd=.5n’ (register ‘t*cpd’).
                     csp=[4mn[24m  Cell spacing, i.e., the extra  space  between  the
                            table  border  or vertical or horizontal lines be‐
                            tween cells and the cellspace.
                            [1mDefault: [22m‘csp=.5n’ (register ‘t*csp’).
                     tal=l|c|r
                            Horizontal  alignment  of  the  table,  if  it  is
                            smaller than the line width.  ‘tal=l’: left align‐
                            ment.    ‘tal=c’:  centered  alignment.   ‘tal=r’:
                            right alignment.
                            [1mDefault: [22m‘tal=l’ (register ‘t*tal’).
                     width='[4mw1[24m [[4mw2[24m [...]]'
                            Widths of table cells.  [4mw1[24m,  [4mw2[24m,  ...  are  either
                            numbers  of  type  [4mn[24m  or  natural numbers with the
                            pseudo‐scaling indicator  ‘%’,  with  the  meaning
                            “percent  of  the  actual  line  length (or column
                            length for inner tables, respectively)”.  If there
                            are less width values than table columns, the last
                            width value is used for the remaining cells.   The
                            argument

                                   width='1.5i 10%'

                            for  example  indicates  that  the first column is
                            1.5 inches wide; the remaining columns  take  1/10
                            of the column length each.
                            [1mDefault:  [22mThe  table  width  equals the outer line
                            length or column length; the  columns  have  equal
                            widths.
                     height=[4mn[0m
                            Height  of  the table.  If the table with its con‐
                            tents is lower than [4mn[24m, the last row  is  stretched
                            to this value.

       [1m.CPTN [22m[[4margs[24m]
              Text of caption.

              The (optionally numbered) table caption.  .CPTN is optional.

              [1mpredecessor: [22m.TBL
              [1msuccessor: [22m.TR
              [1marguments:[0m
                     val=t|b
                            Vertical alignment of the table caption.  ‘val=t’:
                            The  caption  is placed above the table.  ‘val=b’:
                            The caption is placed below the table.
                            [1mDefault: [22m‘val=t’ (string ‘t*cptn’).

       [1m.TR [22m[[4margs[24m]
              Begin a new table row.

              [1mpredecessor: [22m.TBL, .CPTN, .TD, .TH, .ETB, cell contents
              [1msuccessor: [22m.TD, .TH
              [1marguments:[0m
                     height=[4mn[0m
                            The height of the row.  If a cell in  the  row  is
                            higher  than  [4mn[24m,  this value is ignored; otherwise
                            the row height is stretched to [4mn[24m.

       [1m.TD [22m[[4margs[24m [[4mcell[24m [4mcontents[24m]]
              Begin a table data cell.
       [1m.TH [22m[[4margs[24m [[4mcell[24m [4mcontents[24m]]
              Begin a table header cell.

              Arguments and cell contents can be mixed.  The macro .TH is  not
              really necessary and differs from .TD only in three default set‐
              tings,  similar  to the <TH> and <TD> HTML tags: The contents of
              .TH is horizontally and vertically centered and typeset in bold‐
              face.

              [1mpredecessor: [22m.TR, .TD, .TH, .ETB, cell contents
              [1msuccessor: [22m.TD, .TH, .TR, .ETB, cell contents
              [1marguments:[0m
                     colspan=[4mm[0m
                            The width of this cell is the sum of the widths of
                            the [4mm[24m cells above and below this row.
                     rowspan=[4mm[0m
                            The height of this cell is the sum of the  heights
                            of the [4mm[24m cells left and right of this column.

                            [1mRemark: [22mOverlapping of column and row spanning, as
                            in  the  following table fragment (the overlapping
                            happens in the second cell in the second row),  is
                            invalid and causes incorrect results.

                                   .TR .TD 1*1 ".TD 1*2 rowspan=2" .TD 1*3
                                   .TR ".TD 2*1 colspan=2"         .TD 2*3

                     A working example for headers and cells with [1mcolspan [22mis

                            .TBL cols=3
                            .  TR ".TH colspan=2" header1+2 .TH header3
                            .  TR .TD 1*1 .TD 1*2 .TD 1*3
                            .  TR .TD 2*1 ".TD colspan=2" 2*2+3
                            .ETB

                     This looks like

                            +------------------------------+---------------+
                            |          header1+2           |    header3    |
                            +--------------+---------------+---------------+
                            | 1*1          | 1*2           | 1*3           |
                            +--------------+---------------+---------------+
                            | 2*1          | 2*2+3                         |
                            +--------------+-------------------------------+

                     A working example with [1mrowspan [22mis

                            .TBL cols=3
                            .  TR
                            .  TD 1*1
                            .  TD rowspan=2 1+2*2
                            .  TD 1*3
                            .
                            .  TR
                            .  TD 2*1
                            .  TD 2*3
                            .ETB

                     which looks like

                            +--------------+---------------+---------------+
                            | 1*1          | 1+2*2         | 1*3           |
                            +--------------+               +---------------+
                            | 2*1          |               | 2*3           |
                            +--------------+---------------+---------------+

       [1m.ETB [22m[[1mhold[22m]
              End of the table.

              This macro finishes a table.  It causes one of the following ac‐
              tions.

              •  If  the  argument ‘hold’ is given, the table is held until it
                 is freed by calling the macro .t*free, which in  turn  prints
                 the  table  immediately, either at the current position or at
                 the top of the next page if its height is larger than the re‐
                 maining space on the page.

              •  Otherwise, if the table is higher than the remaining space on
                 the page, it is printed at the top of the next page.

              •  If neither of the two above constraints hold,  the  table  is
                 printed immediately at the place of its definition.

              [1mpredecessor: [22m.TD, .TH, .ETB, cell contents
              [1msuccessor: [22m.TBL, .TR, .TD, .TH, .ETB, cell contents
              [1marguments:[0m
                     hold   Prevent  the  table from being printed until it is
                            freed by calling the macro .t*free.  This argument
                            is ignored for inner (nested) tables.

       [1m.t*free [22m[[4mn[24m]
              Free the next held table or [4mn[24m held tables.   Call  this  utility
              macro  to  print tables which are held by using the ‘hold’ argu‐
              ment of the .ETB macro.

   [1mArguments common to .TBL, .TR, .TD, and .TH[0m
       The arguments described in this section can be specified with the  .TBL
       and  .TR  macros, but they are eventually passed on to the table cells.
       If omitted, the defaults take place, which the user can change by  set‐
       ting  the corresponding default registers or strings, as documented be‐
       low.  Setting an argument with the .TBL macro has the  same  effect  as
       setting  it  for all rows in the table.  Setting an argument with a .TR
       macro has the same effect as setting it for all the .TH or .TD macro in
       this row.

       bgc=[[4mc[24m]
              The background color of the table cells.  This includes the area
              specified with the ‘csp’  argument.   The  argument  ‘bgc=’  (no
              value)  suppresses a background color; this makes the background
              transparent.
              [1mDefault: [22m‘bgc=bisque’ (string ‘t*bgc’).
       fgc=[4mc[24m  The foreground color of the cell contents.
              [1mDefault: [22m‘fgc=red4’ (string ‘t*fgc’).
       ff=[4mname[0m
              The font family for the table.  [4mname[24m  is  a  [4mgroff[24m  font  family
              identifier,  such  as A for Avant Garde or HN for Helvetica Nar‐
              row.
              [1mDefault: [22mThe font family found before the table (string ‘t*ff’).
       fst=[4mstyle[0m
              The font style for the table.  One of R, B, I, or BI for  roman,
              [1mbold[22m,  [4mitalic[24m, or [4m[1mbold[24m [4mitalic[24m[22m, respectively.  As with [4mroff[24m’s [1m.ft[0m
              request, the ‘fst’ argument can be used to specify the font fam‐
              ily and font style together, for example ‘fst=HNBI’  instead  of
              ‘ff=HN’ and ‘fst=BI’.
              [1mDefault:  [22mThe  font  style in use right before the table (string
              ‘t*fst’).
       fsz='[4md1[24m [[4md2[24m]'
              A decimal or fractional factor [4md1[24m, by which the point  size  for
              the table is changed, and [4md2[24m, by which the vertical line spacing
              is changed.  If [4md2[24m is omitted, value [4md1[24m is taken for both.
              [1mDefault: [22m‘fsz='1.0 1.0'’ (string ‘t*fsz’).
       hal=l|c|b|r
              Horizontal   alignment  of  the  cell  contents  in  the  table.
              ‘hal=l’: left alignment.  ‘hal=c’: centered alignment.  ‘hal=b’:
              both (left and right) alignment.  ‘hal=r’: right alignment.
              [1mDefault: [22m‘hal=b’ (string ‘t*hal’).
       val=t|m|b
              Vertical alignment of the cell contents in the table  for  cells
              lower than the current row.  ‘val=t’: alignment below the top of
              the  cell.   ‘val=m’:  alignment  in  the  middle  of  the cell.
              ‘val=b’: alignment above the cell bottom.
              [1mDefault: [22m‘val=t’ (string ‘t*val’).
       hl=[s|d]
              Horizontal line between the rows.  If specified with .TD or  .TH
              this  is  a separator line to the cell below.  ‘hl=’ (no value):
              no separator line.  ‘hl=s’: a single separator line between  the
              rows.  ‘hl=d’: a double separator line.

              The  thickness  of the separator lines is the half of the border
              thickness, but at least 0.1 inches.  The  distance  between  the
              double lines is equal to the line thickness.

              [1mRemark: [22mTogether with ‘border=0’ for proper formatting the value
              of  ‘csp’ must be at least .05 inches for single separator lines
              and .15 inches for double separator lines.
              [1mDefault: [22m‘hl=s’ (string ‘t*hl’).
       vl=[s|d]
              Vertical separator line between the cells.   If  specified  with
              .TD  or  .TH  this is a separator line to the cell on the right.
              ‘vl=s’: a single separator line between the  cells.   ‘vl=d’:  a
              double separator line.  ‘vl=’ (no value): no vertical cell sepa‐
              rator  lines.  For more information see the documentation of the
              ‘hl’ argument above.
              [1mDefault: [22m‘vl=s’ (string ‘t*vl’).

[4m[1mhdtbl[24m customization[0m
       Before creating the first table, you should configure default values to
       minimize the markup needed in each table.  The following  example  sets
       up defaults suitable for typical papers:

              .ds t*bgc white\" background color
              .ds t*fgc black\" foreground color
              .ds t*bc black\"  border color
              .nr t*cpd 0.1n\"  cell padding

       The  file  [4m/usr/share/doc/groff-1.23.0/examples/hdtbl/common.roff[24m  pro‐
       vides another example setup in the “minimal Page setup” section.

       A table which does not fit on a partially filled page is printed  auto‐
       matically  on the top of the next page if you append the little utility
       macro t*hm to the page header macro of your document’s main macro pack‐
       age.  For example, say

              .am pg@top
              .  t*hm
              ..

       if you use the [4mms[24m macro package.

       The macro t*EM checks for held or kept  tables,  and  for  missing  ETB
       macros (table not closed).  You can call this macro by appending it the
       to  end‐of‐input  macro  of  the main, or “full‐service”, macro package
       your document uses.  For example, try
              .am pg@end-text
              .  t*EM
              ..
       if you use the [4mms[24m package.

[1mBugs and suggestions[0m
       Please send your comments to the [4mgroff[24m mailing list ⟨groff@gnu.org⟩  or
       directly to the author.

[1mAuthors[0m
       The  [4mhdtbl[24m  macro  package  was  written  by Joachim Walsdorff ⟨Joachim
       .Walsdorff@urz.uni-heidelberg.de⟩.

[1mSee also[0m
       [4mgroff[24m(1)
              provides an overview of GNU [4mroff[24m and details how to invoke [4mgroff[0m
              at the command line.

       [4mgroff[24m(7)
              summarizes the [4mroff[24m language and GNU extensions to it.

       [4mtbl[24m(1) describes the traditional [4mroff[24m preprocessor for tables.

groff 1.23.0                      5 July 2023                   [4mgroff_hdtbl[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_man[24m(7)           Miscellaneous Information Manual           [4mgroff_man[24m(7)

[1mName[0m
       groff_man - compose manual pages with GNU [4mroff[0m

[1mSynopsis[0m
       [1mgroff -man [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff -m man [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       The GNU implementation of the [4mman[24m macro package is part  of  the  [4mgroff[0m
       document  formatting  system.   It  is  used  to  produce  manual pages
       (“man pages”) like the one you are reading.

       This document presents the macros thematically; for those needing  only
       a  quick reference, the following table lists them alphabetically, with
       cross references to appropriate subsections below.

       Man page authors and maintainers who are not already experienced  [4mgroff[0m
       users  should  consult  [4mgroff_man_style[24m(7), an expanded version of this
       document, for additional explanations and advice.  It covers only those
       concepts required for man page document maintenance, and not  the  full
       breadth of the [4mgroff[24m typesetting system.

       Macro   Meaning                      Subsection
       ───────────────────────────────────────────────────────────────
       [1m.B      [22mBold                         Font style macros
       [1m.BI     [22mBold, italic alternating     Font style macros
       [1m.BR     [22mBold, roman alternating      Font style macros
       [1m.EE     [22mExample end                  Document structure macros
       [1m.EX     [22mExample begin                Document structure macros
       [1m.I      [22mItalic                       Font style macros
       [1m.IB     [22mItalic, bold alternating     Font style macros
       [1m.IP     [22mIndented paragraph           Paragraphing macros
       [1m.IR     [22mItalic, roman alternating    Font style macros
       [1m.LP     [22mBegin paragraph              Paragraphing macros
       [1m.ME     [22mMail‐to end                  Hyperlink macros
       [1m.MR     [22mMan page cross reference     Hyperlink macros
       [1m.MT     [22mMail‐to start                Hyperlink macros
       [1m.P      [22mBegin paragraph              Paragraphing macros
       [1m.PP     [22mBegin paragraph              Paragraphing macros
       [1m.RB     [22mRoman, bold alternating      Font style macros
       [1m.RE     [22mRelative inset end           Document structure macros
       [1m.RI     [22mRoman, italic alternating    Font style macros
       [1m.RS     [22mRelative inset start         Document structure macros
       [1m.SB     [22mSmall bold                   Font style macros
       [1m.SH     [22mSection heading              Document structure macros
       [1m.SM     [22mSmall                        Font style macros
       [1m.SS     [22mSubsection heading           Document structure macros
       [1m.SY     [22mSynopsis start               Command synopsis macros
       [1m.TH     [22mTitle heading                Document structure macros
       [1m.TP     [22mTagged paragraph             Paragraphing macros
       [1m.TQ     [22mSupplemental paragraph tag   Paragraphing macros
       [1m.UE     [22mURI end                      Hyperlink macros
       [1m.UR     [22mURI start                    Hyperlink macros
       [1m.YS     [22mSynopsis end                 Command synopsis macros

       We  discuss  other macros ([1m.AT[22m, [1m.DT[22m, [1m.HP[22m, [1m.OP[22m, [1m.PD[22m, and [1m.UC[22m) in subsec‐
       tion “Deprecated features” below.

       Throughout Unix documentation, a manual entry is referred to simply  as
       a  “man  page”, regardless of its length, without gendered implication,
       and irrespective of the macro package selected for its composition.

   [1mMacro reference preliminaries[0m
       A tagged paragraph describes each macro.  We present coupled pairs  to‐
       gether, as with [1m.EX [22mand [1m.EE[22m.

       An  empty  macro argument can be specified with a pair of double‐quotes
       (""), but the [4mman[24m package is designed such that this should  seldom  be
       necessary.   Most macro arguments will be formatted as text in the out‐
       put; exceptions are noted.

   [1mDocument structure macros[0m
       Document structure macros organize a man page’s content.  All  of  them
       break  the output line.  [1m.TH [22m(title heading) identifies the document as
       a man page and configures the page headers and footers.  Section  head‐
       ings ([1m.SH[22m), one of which is mandatory and many of which are convention‐
       ally  expected,  facilitate  location of material by the reader and aid
       the man page writer to discuss all  essential  aspects  of  the  topic.
       Subsection  headings  ([1m.SS[22m)  are optional and permit sections that grow
       long to develop in a controlled way.  Many technical discussions  bene‐
       fit  from  examples; lengthy ones, especially those reflecting multiple
       lines of input to or output from the system, are usefully bracketed  by
       [1m.EX [22mand [1m.EE[22m.  When none of the foregoing meets a structural demand, use
       [1m.RS[22m/[1m.RE [22mto inset a region within a (sub)section.

       [1m.TH [4m[22mtopic[24m [4msection[24m [[4mfooter‐middle[24m] [[4mfooter‐inside[24m] [[4mheader‐middle[24m]
              Determine  the contents of the page header and footer.  The sub‐
              ject of the man page is [4mtopic[24m and the section of the  manual  to
              which  it  belongs  is  [4msection.[24m  See [4mman[24m(1) or [4mintro[24m(1) for the
              manual sectioning applicable to your system.  [4mtopic[24m and  [4msection[0m
              are  positioned  together  at  the  left and right in the header
              (with [4msection[24m in parentheses  immediately  appended  to  [4mtopic[24m).
              [4mfooter‐middle[24m is centered in the footer.  The arrangement of the
              rest of the footer depends on whether double‐sided layout is en‐
              abled  with  the  option  [1m-rD1[22m.   When  disabled  (the default),
              [4mfooter‐inside[24m is positioned  at  the  bottom  left.   Otherwise,
              [4mfooter‐inside[24m appears at the bottom left on recto (odd‐numbered)
              pages,  and  at the bottom right on verso (even‐numbered) pages.
              The outside footer is the page number, except in the continuous‐
              rendering mode enabled by the option [1m-rcR=1[22m, in which case it is
              the [4mtopic[24m and [4msection,[24m as in the header.  [4mheader‐middle[24m is  cen‐
              tered  in  the header.  If [4msection[24m is an integer between 1 and 9
              (inclusive), there is no need to specify [4mheader‐middle;[24m  [4man.tmac[0m
              will  supply text for it.  The macro package may also abbreviate
              [4mtopic[24m and [4mfooter‐inside[24m with ellipses if they would overrun  the
              space  available  in  the  header and footer, respectively.  For
              HTML output, headers and footers are suppressed.

              Additionally, this macro breaks the page, resetting  the  number
              to  1  (unless  the  [1m-rC1 [22moption is given).  This feature is in‐
              tended only for formatting multiple [4mman[24m documents in sequence.

              A valid [4mman[24m document calls [1m.TH [22monce, early in the file, prior to
              any other macro calls.

       [1m.SH [22m[[4mheading‐text[24m]
              Set [4mheading‐text[24m as a section heading.  If no argument is given,
              a one‐line input trap is planted; text on the next line  becomes
              [4mheading‐text.[24m  The left margin is reset to zero to set the head‐
              ing  text in bold (or the font specified by the string [1mHF[22m), and,
              on typesetting devices, slightly larger than the base type size.
              If the heading font [1m\*[HF] [22mis bold, use of an  italic  style  in
              [4mheading‐text[24m  is mapped to the bold‐italic style if available in
              the font family.  The inset level is reset  to  1,  setting  the
              left  margin  to the value of the [1mIN [22mregister.  Text after [4mhead‐[0m
              [4ming‐text[24m is set as an ordinary paragraph ([1m.P[22m).

              The content of [4mheading‐text[24m and ordering of sections  follows  a
              set  of  common practices, as has much of the layout of material
              within sections.  For example, a section called “Name” or “NAME”
              must exist, must be the first section after the  [1m.TH  [22mcall,  and
              must contain only text of the form
                     [4mtopic[24m[[1m, [4m[22manother‐topic[24m]... \- [4msummary‐description[0m
              for  a  man page to be properly indexed.  See [4mgroff_man_style[24m(7)
              for suggestions and [4mman[24m(7) for  the  conventions  prevailing  on
              your system.

       [1m.SS [22m[[4msubheading‐text[24m]
              Set  [4msubheading‐text[24m  as a subsection heading indented between a
              section heading and an ordinary paragraph ([1m.P[22m).  If no  argument
              is  given,  a  one‐line  input trap is planted; text on the next
              line becomes [4msubheading‐text.[24m  The left margin is reset  to  the
              value of the [1mSN [22mregister to set the heading text in bold (or the
              font specified by the string [1mHF[22m).  If the heading font [1m\*[HF] [22mis
              bold, use of an italic style in [4msubheading‐text[24m is mapped to the
              bold‐italic  style  if  available in the font family.  The inset
              level is reset to 1, setting the left margin to the value of the
              [1mIN [22mregister.  Text after [4msubheading‐text[24m is set as  an  ordinary
              paragraph ([1m.P[22m).

       [1m.EX[0m
       [1m.EE    [22mBegin  and  end  example.   After [1m.EX[22m, filling is disabled and a
              constant‐width (monospaced) font is selected.  Calling  [1m.EE  [22men‐
              ables filling and restores the previous font.

              These macros are extensions introduced in Ninth Edition Research
              Unix.   Systems  running  that [4mtroff[24m, or those from Documenter’s
              Workbench, Heirloom Doctools, or Plan 9 [4mtroff[24m support them.   To
              be  certain  your  page will be portable to systems that do not,
              copy their definitions from the [4man-ext.tmac[24m file of a [4mgroff[24m  in‐
              stallation.

       [1m.RS [22m[[4minset‐amount[24m]
              Start a new relative inset level.  The position of the left mar‐
              gin  is  saved,  then moved right by [4minset‐amount,[24m if specified,
              and by the amount of the [1mIN [22mregister otherwise.   Calls  to  [1m.RS[0m
              can be nested; each increments by 1 the inset level used by [1m.RE[22m.
              The level prior to any [1m.RS [22mcalls is 1.

       [1m.RE [22m[[4mlevel[24m]
              End  a  relative  inset.  The left margin corresponding to inset
              level [4mlevel[24m is restored.  If no argument  is  given,  the  inset
              level is reduced by 1.

   [1mParagraphing macros[0m
       An  ordinary  paragraph ([1m.P[22m) is set without a first‐line indentation at
       the current left margin.  In man pages and other technical  literature,
       definition  lists  are  frequently  encountered;  these  can  be set as
       “tagged paragraphs”, which have one ([1m.TP[22m) or more  ([1m.TQ[22m)  leading  tags
       followed  by  a  paragraph that has an additional indentation.  The in‐
       dented paragraph ([1m.IP[22m) macro is useful to continue the indented content
       of a narrative started with [1m.TP[22m, or to present an itemized  or  ordered
       list.  All of these macros break the output line.  If another paragraph
       macro has occurred since the previous [1m.SH [22mor [1m.SS[22m, they (except for [1m.TQ[22m)
       follow  the break with a default amount of vertical space, which can be
       changed by the deprecated [1m.PD [22mmacro;  see  subsection  “Horizontal  and
       vertical  spacing” below.  They also reset the type size and font style
       to defaults ([1m.TQ [22magain excepted); see subsection  “Font  style  macros”
       below.

       [1m.P[0m
       [1m.LP[0m
       [1m.PP    [22mBegin  a new paragraph; these macros are synonymous.  The inden‐
              tation is reset to the default value; the left  margin,  as  af‐
              fected by [1m.RS [22mand [1m.RE[22m, is not.

       [1m.TP [22m[[4mindentation[24m]
              Set  a  paragraph  with  a leading tag, and the remainder of the
              paragraph indented.  A one‐line input trap is planted;  text  on
              the  next line, which can be formatted with a macro, becomes the
              tag, which is placed at the current left margin.  The tag can be
              extended with the [1m\c [22mescape sequence.  Subsequent  text  is  in‐
              dented by [4mindentation,[24m if specified, and by the amount of the [1mIN[0m
              register  otherwise.   If the tag is not as wide as the indenta‐
              tion, the paragraph starts on the same line as the tag,  at  the
              applicable  indentation,  and  continues on the following lines.
              Otherwise, the descriptive part of the paragraph begins  on  the
              line following the tag.

       [1m.TQ    [22mSet an additional tag for a paragraph tagged with [1m.TP[22m.  An input
              trap is planted as with [1m.TP[22m.

              This  macro  is  a  GNU extension not defined on systems running
              AT&T, Plan 9, or  Solaris  [4mtroff[24m;  see  [4man-ext.tmac[24m  in  section
              “Files” below.

       [1m.IP [22m[[4mtag[24m] [[4mindentation[24m]
              Set an indented paragraph with an optional tag.  The [4mtag[24m and [4min‐[0m
              [4mdentation[24m  arguments,  if present, are handled as with [1m.TP[22m, with
              the exception that the [4mtag[24m argument  to  [1m.IP  [22mcannot  include  a
              macro call.

   [1mCommand synopsis macros[0m
       [1m.SY  [22mand [1m.YS [22maid you to construct a command synopsis that has the clas‐
       sical Unix appearance.  They break the output line.

       These macros are GNU extensions not defined on  systems  running  AT&T,
       Plan 9, or Solaris [4mtroff[24m; see [4man-ext.tmac[24m in section “Files” below.

       [1m.SY [4m[22mcommand[0m
              Begin  synopsis.   A new paragraph begins at the left margin un‐
              less [1m.SY [22mhas already been called without a corresponding [1m.YS[22m, in
              which case only a break is performed.  Adjustment and  automatic
              hyphenation  are  disabled.  [4mcommand[24m is set in bold.  If a break
              is required, lines after the first are indented by the width  of
              [4mcommand[24m plus a space.

       [1m.YS    [22mEnd  synopsis.  Indentation, adjustment, and hyphenation are re‐
              stored to their previous states.

   [1mHyperlink macros[0m
       Man page cross references are best presented with [1m.MR[22m.  Text may be hy‐
       perlinked to email addresses with [1m.MT[22m/[1m.ME [22mor other URIs  with  [1m.UR[22m/[1m.UE[22m.
       Hyperlinked text is supported on HTML and terminal output devices; ter‐
       minals  and  pager programs must support ECMA‐48 OSC 8 escape sequences
       (see [4mgrotty[24m(1)).  When device support is unavailable or  disabled  with
       the [1mU [22mregister (see section “Options” below), [1m.MT [22mand [1m.UR [22mURIs are ren‐
       dered between angle brackets after the linked text.

       [1m.MT[22m,  [1m.ME[22m,  [1m.UR[22m, and [1m.UE [22mare GNU extensions not defined on systems run‐
       ning AT&T, Plan 9, or Solaris [4mtroff[24m; see [4man-ext.tmac[24m in section “Files”
       below.  Plan 9 from User Space’s [4mtroff[24m implements [1m.MR[22m.

       The arguments to [1m.MR[22m, [1m.MT[22m, and [1m.UR [22mshould be prepared  for  typesetting
       since  they can appear in the output.  Use special character escape se‐
       quences to encode Unicode basic Latin characters where necessary,  par‐
       ticularly  the hyphen‐minus.  The formatter removes [1m\: [22mescape sequences
       from hyperlinks when supplying device control commands to  output  dri‐
       vers.

       [1m.MR [4m[22mtopic[24m [4mmanual‐section[24m [[4mtrailing‐text[24m]
              [4m(since[24m groff [4m1.23)[24m Set a man page cross reference as “[4mtopic[24m[1m([4m[22mman‐[0m
              [4mual‐section[24m[1m)[22m”.   If  [4mtrailing‐text[24m  (typically  punctuation)  is
              specified, it follows the closing parenthesis without  interven‐
              ing space.  Hyphenation is disabled while the cross reference is
              set.   [4mtopic[24m is set in the font specified by the [1mMF [22mstring.  The
              cross reference hyperlinks to a URI of the form  “[1mman:[4m[22mtopic[24m([4mman‐[0m
              [4mual‐section[24m)”.

       [1m.MT [4m[22maddress[0m
       [1m.ME [22m[[4mtrailing‐text[24m]
              Identify  [4maddress[24m  as  an RFC 6068 [4maddr‐spec[24m for a “mailto:” URI
              with the text between the two macro calls as the link text.   An
              argument  to [1m.ME [22mis placed after the link text without interven‐
              ing space.  [4maddress[24m may not be visible in the rendered  document
              if  hyperlinks  are  enabled and supported by the output driver.
              If they are not, [4maddress[24m is set in angle brackets after the link
              text and before [4mtrailing‐text.[24m  If hyperlinking is  enabled  but
              there  is  no  link  text,  [4maddress[24m is formatted and hyperlinked
              [4mwithout[24m angle brackets.

       [1m.UR [4m[22muri[0m
       [1m.UE [22m[[4mtrailing‐text[24m]
              Identify [4muri[24m as an RFC 3986 URI hyperlink with the text  between
              the  two  macro  calls  as the link text.  An argument to [1m.UE [22mis
              placed after the link text without intervening space.   [4muri[24m  may
              not  be  visible  in the rendered document if hyperlinks are en‐
              abled and supported by the output driver.  If they are not,  [4muri[0m
              is  set  in angle brackets after the link text and before [4mtrail‐[0m
              [4ming‐text.[24m  If hyperlinking is enabled but there is no link text,
              [4muri[24m is formatted and hyperlinked [4mwithout[24m angle brackets.

       The hyperlinking of [1m.TP [22mparagraph tags with [1m.UR[22m/[1m.UE [22mand [1m.MT[22m/[1m.ME [22mis  not
       yet  supported;  if attempted, the hyperlink will be typeset at the be‐
       ginning of the indented paragraph even on hyperlink‐supporting devices.

   [1mFont style macros[0m
       The [4mman[24m macro package is limited in its font styling options,  offering
       only [1mbold [22m([1m.B[22m), [4mitalic[24m ([1m.I[22m), and roman.  Italic text is usually set un‐
       derscored instead on terminal devices.  The [1m.SM [22mand [1m.SB [22mmacros set text
       in  roman  or  bold, respectively, at a smaller type size; these differ
       visually from regular‐sized roman or bold text only on typesetting  de‐
       vices.   It  is often necessary to set text in different styles without
       intervening space.  The macros [1m.BI[22m, [1m.BR[22m, [1m.IB[22m, [1m.IR[22m, [1m.RB[22m, and [1m.RI[22m,  where
       “B”,  “I”,  and “R” indicate bold, italic, and roman, respectively, set
       their odd‐ and even‐numbered arguments in alternating styles,  with  no
       space separating them.

       The  default  type  size and family for typesetting devices is 10‐point
       Times, except on the [1mX75-12 [22mand [1mX100-12 [22mdevices where the type size  is
       12 points.  The default style is roman.

       [1m.B [22m[[4mtext[24m]
              Set  [4mtext[24m  in  bold.   If no argument is given, a one‐line input
              trap is planted; text on the next line,  which  can  be  further
              formatted with a macro, is set in bold.

       [1m.I [22m[[4mtext[24m]
              Set [4mtext[24m in an italic or oblique face.  If no argument is given,
              a  one‐line  input trap is planted; text on the next line, which
              can be further formatted with a macro, is set in  an  italic  or
              oblique face.

       [1m.SM [22m[[4mtext[24m]
              Set  [4mtext[24m  one point smaller than the default type size on type‐
              setting devices.  If no argument is given, a one‐line input trap
              is planted; text on the next line, which can be further  format‐
              ted with a macro, is set smaller.

       [1m.SB [22m[[4mtext[24m]
              Set  [4mtext[24m in bold and (on typesetting devices) one point smaller
              than the default type size.  If no argument is given, a one‐line
              input trap is planted; text on the next line, which can be  fur‐
              ther  formatted  with a macro, is set smaller and in bold.  This
              macro is an extension introduced in SunOS 4.0.

       Unlike the above font style macros, the font style  alternation  macros
       below  set no input traps; they must be given arguments to have effect.
       Italic corrections are applied as appropriate.

       [1m.BI [4m[22mbold‐text[24m [4mitalic‐text[24m ...
              Set each argument in bold and italics, alternately.

       [1m.BR [4m[22mbold‐text[24m [4mroman‐text[24m ...
              Set each argument in bold and roman, alternately.

       [1m.IB [4m[22mitalic‐text[24m [4mbold‐text[24m ...
              Set each argument in italics and bold, alternately.

       [1m.IR [4m[22mitalic‐text[24m [4mroman‐text[24m ...
              Set each argument in italics and roman, alternately.

       [1m.RB [4m[22mroman‐text[24m [4mbold‐text[24m ...
              Set each argument in roman and bold, alternately.

       [1m.RI [4m[22mroman‐text[24m [4mitalic‐text[24m ...
              Set each argument in roman and italics, alternately.

   [1mHorizontal and vertical spacing[0m
       The [4mindentation[24m argument accepted by [1m.IP[22m, [1m.TP[22m, and the  deprecated  [1m.HP[0m
       is  a  number  plus an optional scaling unit, as is [1m.RS[22m’s [4minset‐amount[24m.
       If no scaling unit is given, the [4mman[24m package assumes “n”.  An  indenta‐
       tion  specified  in  a call to [1m.IP[22m, [1m.TP[22m, or the deprecated [1m.HP [22mpersists
       until (1) another of these macros is called with an  [4mindentation[24m  argu‐
       ment, or (2) [1m.SH[22m, [1m.SS[22m, or [1m.P [22mor its synonyms is called; these clear the
       indentation entirely.

       The  left  margin used by ordinary paragraphs set with [1m.P [22m(and its syn‐
       onyms) not within an [1m.RS[22m/[1m.RE [22mrelative inset is 7.2n for typesetting de‐
       vices and 7n for terminal devices (but see the [1m-rIN [22moption).   Headers,
       footers  (both set with [1m.TH[22m), and section headings ([1m.SH[22m) are set at the
       page offset (see [4mgroff[24m(7)) and subsection headings ([1m.SS[22m) indented  from
       it by 3n (but see the [1m-rSN [22moption).

       Several  macros  insert vertical space: [1m.SH[22m, [1m.SS[22m, [1m.TP[22m, [1m.P [22m(and its syn‐
       onyms), [1m.IP[22m, and the deprecated [1m.HP[22m.  The default inter‐section and in‐
       ter‐paragraph spacing is is 1v for terminal devices and 0.4v for  type‐
       setting  devices.   (The  deprecated macro [1m.PD [22mcan change this vertical
       spacing, but its use is discouraged.)  Between [1m.EX [22mand [1m.EE  [22mcalls,  the
       inter‐paragraph spacing is 1v regardless of output device.

   [1mRegisters[0m
       Registers  are  described  in section “Options” below.  They can be set
       not only on the command line but in the site [4mman.local[24m  file  as  well;
       see section “Files” below.

   [1mStrings[0m
       The  following strings are defined for use in man pages.  None of these
       is necessary in a contemporary man page; see [4mgroff_man_style[24m(7).   Oth‐
       ers  are  supported for configuration of rendering parameters; see sec‐
       tion “Options” below.

       [1m\*R    [22minterpolates a special character escape sequence for the “regis‐
              tered sign” glyph, [1m\(rg[22m, if available, and “(Reg.)” otherwise.

       [1m\*S    [22minterpolates an escape sequence setting the  type  size  to  the
              document default.

       [1m\*(lq[0m
       [1m\*(rq  [22minterpolate  special  character  escape  sequences  for left and
              right double‐quotation marks, [1m\(lq [22mand [1m\(rq[22m, respectively.

       [1m\*(Tm  [22minterpolates a special character escape sequence for the  “trade
              mark sign” glyph, [1m\(tm[22m, if available, and “(TM)” otherwise.

   [1mHooks[0m
       Two macros, both GNU extensions, are called internally by the [4mgroff[24m [4mman[0m
       package  to format page headers and footers and can be redefined by the
       administrator in a site’s [4mman.local[24m file (see section  “Files”  below).
       The  presentation  of [1m.TH [22mabove describes the default headers and foot‐
       ers.  Because these macros are hooks for [4mgroff[24m [4mman[24m internals, man pages
       have no reason to call them.  Such hook definitions will likely consist
       of “.sp” and “.tl” requests.  They must also increase the  page  length
       with  “.pl”  requests in continuous rendering mode; [1m.PT [22mfurthermore has
       the responsibility of emitting a PDF bookmark after writing  the  first
       page  header  in  a  document.  Consult the existing implementations in
       [4man.tmac[24m when drafting replacements.

       [1m.BT    [22mSet the page footer text (“bottom trap”).

       [1m.PT    [22mSet the page header text (“page trap”).

       To remove a page header or  footer  entirely,  define  the  appropriate
       macro as empty rather than deleting it.

   [1mDeprecated features[0m
       Use  of  the following in man pages for public distribution is discour‐
       aged.

       [1m.AT [22m[[4msystem[24m [[4mrelease[24m]]
              Alter the footer for use with legacy AT&T man pages,  overriding
              any definition of the [4mfooter‐inside[24m argument to [1m.TH[22m.  This macro
              exists only to render man pages from historical systems.

              [4msystem[24m can be any of the following.

                     3      7th edition [4m(default)[0m

                     4      System III

                     5      System V

              The  optional  [4mrelease[24m argument specifies the release number, as
              in “System V Release 3”.

       [1m.DT    [22mReset tab stops to the default (every 0.5i).

              Use of  this  presentation‐oriented  macro  is  deprecated.   It
              translates  poorly  to HTML, under which exact space control and
              tabulation are not readily available.  Thus, information or dis‐
              tinctions that you use tab stops to express  are  likely  to  be
              lost.   If  you  feel  tempted to change the tab stops such that
              calling this macro later  is  desirable  to  restore  them,  you
              should probably be composing a table using [4mtbl[24m(1) instead.

       [1m.HP [22m[[4mindentation[24m]
              Set  up a paragraph with a hanging left indentation.  The [4minden‐[0m
              [4mtation[24m argument, if present, is handled as with [1m.TP[22m.

              Use of this presentation‐oriented macro is deprecated.  A  hang‐
              ing  indentation  cannot  be expressed naturally under HTML, and
              non‐[4mroff[24m‐based man page interpreters may treat [1m.HP [22mas  an  ordi‐
              nary  paragraph.   Thus, information or distinctions you mean to
              express with indentation may be lost.

       [1m.OP [4m[22moption‐name[24m [[4moption‐argument[24m]
              Indicate an optional command parameter called [4moption‐name[24m, which
              is set in bold.  If the option takes an  argument,  specify  [4mop‐[0m
              [4mtion‐argument[24m  using  a  noun,  abbreviation, or hyphenated noun
              phrase.  If present, [4moption‐argument[24m is preceded by a space  and
              set  in  italics.   Square brackets in roman surround both argu‐
              ments.

              Use of this quasi‐semantic macro, an  extension  originating  in
              Documenter’s  Workbench  [4mtroff[24m, is deprecated.  It cannot easily
              be used to annotate options that take optional arguments or  op‐
              tions whose arguments have internal structure (such as a mixture
              of  literal  and  variable  components).   One could work around
              these limitations with font selection escape sequences,  but  it
              is preferable to use font style alternation macros, which afford
              greater flexibility.

       [1m.PD [22m[[4mvertical‐space[24m]
              Define  the  vertical space between paragraphs or (sub)sections.
              The optional argument [4mvertical‐space[24m specifies the  amount;  the
              default  scaling  unit is “v”.  Without an argument, the spacing
              is reset to its default value; see  subsection  “Horizontal  and
              vertical spacing” above.

              Use  of  this  presentation‐oriented  macro  is  deprecated.  It
              translates poorly to HTML, under which exact control  of  inter‐
              paragraph  spacing  is not readily available.  Thus, information
              or distinctions that you use [1m.PD [22mto express  are  likely  to  be
              lost.

       [1m.UC [22m[[4mversion[24m]
              Alter  the  footer for use with legacy BSD man pages, overriding
              any definition of the [4mfooter‐inside[24m argument to [1m.TH[22m.  This macro
              exists only to render man pages from historical systems.

              [4mversion[24m can be any of the following.

                     3      3rd Berkeley Distribution [4m(default)[0m

                     4      4th Berkeley Distribution

                     5      4.2 Berkeley Distribution

                     6      4.3 Berkeley Distribution

                     7      4.4 Berkeley Distribution

   [1mHistory[0m
       M. Douglas McIlroy ⟨m.douglas.mcilroy@dartmouth.edu⟩  designed,  imple‐
       mented,  and  documented  the AT&T [4mman[24m macros for Unix Version 7 (1979)
       and employed them to edit the first volume of its [4mProgrammer’s[24m  [4mManual[24m,
       a  compilation  of all man pages supplied by the system.  That [4mman[24m sup‐
       ported the macros listed in this page not described as extensions,  ex‐
       cept  [1m.P [22mand the deprecated [1m.AT [22mand [1m.UC[22m.  The only strings defined were
       [1mR [22mand [1mS[22m; no registers were documented.

       [1m.UC [22mappeared in 3BSD (1980).  Unix System III (1980) introduced [1m.P  [22mand
       exposed  the  registers  [1mIN  [22mand [1mLL[22m, which had been internal to Seventh
       Edition Unix [4mman[24m.  PWB/UNIX 2.0  (1980)  added  the  [1mTm  [22mstring.   4BSD
       (1980)  added  [1mlq [22mand [1mrq [22mstrings.  SunOS 2.0 (1985) recognized [1mC[22m, [1mD[22m, [1mP[22m,
       and [1mX [22mregisters.  4.3BSD (1986) added [1m.AT [22mand [1m.P[22m.   Ninth  Edition  Re‐
       search Unix (1986) introduced [1m.EX [22mand [1m.EE[22m.  SunOS 4.0 (1988) added [1m.SB[22m.

       The  foregoing features were what James Clark implemented in early ver‐
       sions of [4mgroff[24m.  Later, [4mgroff[24m  1.20  (2009)  originated  [1m.SY[22m/[1m.YS[22m,  [1m.TQ[22m,
       [1m.MT[22m/[1m.ME[22m, and [1m.UR[22m/[1m.UE[22m.  Plan 9 from User Space’s [4mtroff[24m introduced [1m.MR [22min
       2020.

[1mOptions[0m
       The  following  [4mgroff[24m options set registers (with [1m-r[22m) and strings (with
       [1m-d[22m) recognized and used by the [4mman[24m macro package.  To ensure  rendering
       consistent  with output device capabilities and reader preferences, man
       pages should never manipulate them.

       [1m-dAD=[4m[22madjustment‐mode[0m
              Set line adjustment to [4madjustment‐mode,[24m which is  typically  “[1mb[22m”
              for  adjustment  to  both margins (the default), or “[1ml[22m” for left
              alignment (ragged right margin).  Any valid argument to  [4mgroff[24m’s
              “.ad”  request  may  be  used.   See  [4mgroff[24m(7)  for  less‐common
              choices.

       [1m-rcR=1 [22mEnable continuous rendering.  Output is not paginated;  instead,
              one  (potentially  very long) page is produced.  This is the de‐
              fault for terminal and HTML devices.  Use [1m-rcR=0 [22mto  disable  it
              on terminal devices; on HTML devices, it cannot be disabled.

       [1m-rC1   [22mNumber  output  pages  consecutively, in strictly increasing se‐
              quence, rather than resetting the page number to 1 (or the value
              of register [1mP[22m) with each new [4mman[24m document.

       [1m-rCS=1 [22mSet section headings (the argument(s) to [1m.SH[22m) in full  capitals.
              This  transformation  is off by default because it discards case
              distinction information.

       [1m-rCT=1 [22mSet the man page topic (the first argument to [1m.TH[22m) in full capi‐
              tals in headers and footers.  This transformation is off by  de‐
              fault because it discards case distinction information.

       [1m-rD1   [22mEnable  double‐sided layout, formatting footers for even and odd
              pages differently; see the  description  of  [1m.TH  [22min  subsection
              “Document structure macros” above.

       [1m-rFT=[4m[22mfooter‐distance[0m
              Set distance of the footer relative to the bottom of the page to
              [4mfooter‐distance;[24m  this  amount is always negative.  At one half‐
              inch above this location, the page text is broken before writing
              the footer.  Ignored if continuous rendering  is  enabled.   The
              default is -0.5i.

       [1m-dHF=[4m[22mheading‐font[0m
              Set  the  font used for section and subsection headings; the de‐
              fault is “[1mB[22m” (bold style of the default family).  Any valid  ar‐
              gument to [4mgroff[24m’s “.ft” request may be used.  See [4mgroff[24m(7).

       [1m-rHY=0 [22mDisable  automatic  hyphenation.   Normally,  it is enabled (1).
              The hyphenation mode is determined by the [4mgroff[24m locale; see sec‐
              tion “Localization“ of [4mgroff[24m(7).

       [1m-rIN=[4m[22mstandard‐indentation[0m
              Set the amount of indentation used for ordinary  paragraphs  ([1m.P[0m
              and  its  synonyms)  and  the default indentation amount used by
              [1m.IP[22m, [1m.RS[22m, [1m.TP[22m, and the deprecated [1m.HP[22m.  See subsection “Horizon‐
              tal and vertical spacing” above for the default.   For  terminal
              devices, [4mstandard‐indentation[24m should always be an integer multi‐
              ple of unit “n” to get consistent indentation.

       [1m-rLL=[4m[22mline‐length[0m
              Set  line  length;  the  default is 78n for terminal devices and
              6.5i for typesetting devices.

       [1m-rLT=[4m[22mtitle‐length[0m
              Set the line length for titles.  By default, it is  set  to  the
              line length (see [1m-rLL [22mabove).

       [1m-dMF=[4m[22mman‐page‐topic‐font[0m
              Set  the  font  used  for  man  page topics named in [1m.TH [22mand [1m.MR[0m
              calls; the default is “[1mI[22m” (italic style of the default  family).
              Any valid argument to [4mgroff[24m’s “.ft” request may be used.  If the
              [1mMF  [22mstring ends in “I”, it is assumed to be an oblique typeface,
              and italic corrections are applied before  and  after  man  page
              topics.

       [1m-rP[4m[22mn[24m   Start enumeration of pages at [4mn[24m.  The default is 1.

       [1m-rS[4m[22mtype‐size[0m
              Use  [4mtype‐size[24m  for  the document’s body text; acceptable values
              are 10, 11, or 12 points.  See subsection  “Font  style  macros”
              above for the default.

       [1m-rSN=[4m[22msubsection‐indentation[0m
              Set  indentation  of  subsection headings to [4msubsection‐indenta‐[0m
              [4mtion.[24m  See subsection “Horizontal and  vertical  spacing”  above
              for the default.

       [1m-rU1   [22mEnable  generation  of  URI hyperlinks in the [4mgrohtml[24m and [4mgrotty[0m
              output drivers.  [4mgrohtml[24m enables them by  default;  [4mgrotty[24m  does
              not,  pending more widespread pager support for OSC 8 escape se‐
              quences.  Use [1m-rU0 [22mto disable hyperlinks; this will make the ar‐
              guments to [1mMT [22mand [1mUR [22mcalls visible in the document text produced
              by link‐capable drivers.

       [1m-rX[4m[22mp[24m   Number successors of page [4mp[24m as [4mp[24ma, [4mp[24mb, [4mp[24mc, and  so  forth.   The
              register  tracking the suffixed page letter uses format “a” (see
              the “.af” request in [4mgroff[24m(7)).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/an.tmac[0m
              Most [4mman[24m macros are defined in this file.  It also loads  exten‐
              sions from [4man-ext.tmac[24m (see below).

       [4m/usr/share/groff/1.23.0/tmac/andoc.tmac[0m
              This  brief  [4mgroff[24m program detects whether the [4mman[24m or [4mmdoc[24m macro
              package is being used by a document and loads the correct  macro
              definitions,  taking advantage of the fact that pages using them
              must call [1m.TH [22mor [1m.Dd[22m, respectively, before any other macros.   A
              [4mman[24m program or user typing, for example, “[1mgroff -mandoc page.1[22m”,
              need  not know which package the file [4mpage.1[24m uses.  Multiple man
              pages, in either format, can  be  handled;  [4mandoc[24m  reloads  each
              macro package as necessary.

       [4m/usr/share/groff/1.23.0/tmac/an-ext.tmac[0m
              Except  for [1m.SB[22m, definitions of macros described above as exten‐
              sions are contained in this file; in some cases, they  are  sim‐
              pler  versions  of definitions appearing in [4man.tmac[24m, and are ig‐
              nored if the formatter is GNU [4mtroff[24m.  They  are  written  to  be
              compatible  with  AT&T [4mtroff[24m and permissively licensed—not copy‐
              lefted.  To reduce the risk of name space collisions, string and
              register names begin only with “[1mm[22m”[1m.  [22mWe encourage man  page  au‐
              thors who are concerned about portability to legacy Unix systems
              to  copy  these definitions into their pages, and maintainers of
              [4mtroff[24m implementations or  work‐alike  systems  that  format  man
              pages to re‐use them.

              The  definitions  for  these  macros are read after a page calls
              [1m.TH[22m, so they will replace any macros of the same names preceding
              it in your file.  If you use your own implementations  of  these
              macros, they must be defined after [1m.TH [22mis called to have any ef‐
              fect.   Furthermore, it is wise to define such page‐local macros
              (if at all) after the “Name” section to accommodate timid  [4mmake‐[0m
              [4mwhatis[24m  or [4mmandb[24m implementations that may give up their scan for
              indexing material early.

       [4m/usr/share/groff/1.23.0/tmac/man.tmac[0m
              This is a wrapper that loads [4man.tmac[24m.

       [4m/usr/share/groff/1.23.0/tmac/mandoc.tmac[0m
              This is a wrapper that loads [4mandoc.tmac[24m.

       [4m/usr/share/groff/site-tmac/man.local[0m
              Put site‐local changes and customizations into this file.

[1mAuthors[0m
       The initial GNU implementation of the [4mman[24m macro package was written  by
       James  Clark.   Later,  Werner Lemberg ⟨wl@gnu.org⟩ supplied the [1mS[22m, [1mLT[22m,
       and [1mcR [22mregisters, the last a 4.3BSD‐Reno [4mmdoc[24m(7) feature.  Larry Kollar
       ⟨kollar@alltel.net⟩ added the [1mFT[22m, [1mHY[22m, and [1mSN [22mregisters; the [1mHF  [22mstring;
       and  the  [1mPT  [22mand  [1mBT [22mmacros.  G. Branden Robinson ⟨g.branden.robinson@
       gmail.com⟩ implemented the [1mAD [22mand [1mMF [22mstrings; [1mCS[22m, [1mCT[22m, and [1mU  [22mregisters;
       and the [1mMR [22mmacro.  Except for [1m.SB[22m, the extension macros were written by
       Lemberg, Eric S. Raymond ⟨esr@thyrsus.com⟩, and Robinson.

       This document was originally written for the Debian GNU/Linux system by
       Susan  G.  Kleinmann ⟨sgk@debian.org⟩.  It was corrected and updated by
       Lemberg and Robinson.  The extension macros were documented by  Raymond
       and Robinson.

[1mSee also[0m
       [4mtbl[24m(1),  [4meqn[24m(1),  and  [4mrefer[24m(1)  are preprocessors used with man pages.
       [4mman[24m(1) describes the man page librarian on your system.   [4mgroff_mdoc[24m(7)
       details the [4mgroff[24m version of the BSD‐originated alternative macro pack‐
       age for man pages.

       [4mgroff_man_style[24m(7), [4mgroff[24m(7), [4mgroff_char[24m(7), [4mman[24m(7)

groff 1.23.0                      5 July 2023                     [4mgroff_man[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_man_style[24m(7)     Miscellaneous Information Manual     [4mgroff_man_style[24m(7)

[1mName[0m
       groff_man_style - GNU [4mroff[24m man page tutorial and style guide

[1mSynopsis[0m
       [1mgroff -man [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff -m man [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       The  GNU  implementation  of the [4mman[24m macro package is part of the [4mgroff[0m
       document formatting  system.   It  is  used  to  produce  manual  pages
       (“man pages”) like the one you are reading.

       This  document presents the macros thematically; for those needing only
       a quick reference, the following table lists them alphabetically,  with
       cross references to appropriate subsections below.

       Macro   Meaning                      Subsection
       ───────────────────────────────────────────────────────────────
       [1m.B      [22mBold                         Font style macros
       [1m.BI     [22mBold, italic alternating     Font style macros
       [1m.BR     [22mBold, roman alternating      Font style macros
       [1m.EE     [22mExample end                  Document structure macros
       [1m.EX     [22mExample begin                Document structure macros
       [1m.I      [22mItalic                       Font style macros
       [1m.IB     [22mItalic, bold alternating     Font style macros
       [1m.IP     [22mIndented paragraph           Paragraphing macros
       [1m.IR     [22mItalic, roman alternating    Font style macros
       [1m.LP     [22mBegin paragraph              Paragraphing macros
       [1m.ME     [22mMail‐to end                  Hyperlink macros
       [1m.MR     [22mMan page cross reference     Hyperlink macros
       [1m.MT     [22mMail‐to start                Hyperlink macros
       [1m.P      [22mBegin paragraph              Paragraphing macros
       [1m.PP     [22mBegin paragraph              Paragraphing macros
       [1m.RB     [22mRoman, bold alternating      Font style macros
       [1m.RE     [22mRelative inset end           Document structure macros
       [1m.RI     [22mRoman, italic alternating    Font style macros
       [1m.RS     [22mRelative inset start         Document structure macros
       [1m.SB     [22mSmall bold                   Font style macros
       [1m.SH     [22mSection heading              Document structure macros
       [1m.SM     [22mSmall                        Font style macros
       [1m.SS     [22mSubsection heading           Document structure macros
       [1m.SY     [22mSynopsis start               Command synopsis macros
       [1m.TH     [22mTitle heading                Document structure macros
       [1m.TP     [22mTagged paragraph             Paragraphing macros
       [1m.TQ     [22mSupplemental paragraph tag   Paragraphing macros
       [1m.UE     [22mURI end                      Hyperlink macros
       [1m.UR     [22mURI start                    Hyperlink macros
       [1m.YS     [22mSynopsis end                 Command synopsis macros

       We  discuss  other macros ([1m.AT[22m, [1m.DT[22m, [1m.HP[22m, [1m.OP[22m, [1m.PD[22m, and [1m.UC[22m) in subsec‐
       tion “Deprecated features” below.

       Throughout Unix documentation, a manual entry is referred to simply  as
       a  “man  page”, regardless of its length, without gendered implication,
       and irrespective of the macro package selected for its composition.

       Man pages should be encoded using Unicode basic Latin code  points  ex‐
       clusively, and employ the Unix line‐ending convention (U+000A only).

   [1mFundamental concepts[0m
       [4mgroff[24m  is  a  programming system for typesetting: we thus often use the
       verb “to set” in the sense “to typeset”.  The formatter  [4mtroff[24m(1)  col‐
       lects  words from the input and [4mfills[24m output lines with as many as will
       fit.  [4mWords[24m are separated by spaces and newlines.  A  transition  to  a
       new  output line is called a [4mbreak.[24m  When formatted, a word may be bro‐
       ken at hyphens, at [1m\% [22mor [1m\: [22mescape sequences (see subsection “Portabil‐
       ity” below), or at predetermined locations if automatic hyphenation  is
       enabled  (see  the  [1m-rHY [22moption in section “Options” below).  An output
       line may be supplemented with [4minter‐sentence[24m [4mspace,[24m and then optionally
       [4madjusted[24m with more space to a consistent line length (see the [1m-dAD  [22mop‐
       tion).  [4mroff[24m(7) details these processes.

       An input line that starts with a dot (.) or neutral apostrophe (') is a
       [4mcontrol[24m  [4mline.[24m   To call a macro, put its name after a dot on a control
       line.  We refer to macros in this  document  using  this  leading  dot.
       Some  macros  interpret [4marguments,[24m words that follow the macro name.  A
       newline, unless escaped (see subsection “Portability” below), marks the
       end of the macro call.  An input line consisting of a dot followed by a
       newline is called the [4mempty[24m [4mrequest;[24m it does nothing.  [4mText[24m  [4mlines[24m  are
       input lines that are not control lines.

       We  describe  below several [4mman[24m macros that plant one‐line [4minput[24m [4mtraps:[0m
       the next input line that directly produces formatted output is  treated
       specially.  For [4mman[24m documents that follow the advice in section “Porta‐
       bility”  below,  this  means that control lines using the empty request
       and uncommented input lines ending  with  an  escaped  newline  do  not
       spring  the  trap;  anything  else does (but see the [1m.TP [22mmacro descrip‐
       tion).

   [1mMacro reference preliminaries[0m
       A tagged paragraph describes each macro.  We present coupled pairs  to‐
       gether, as with [1m.EX [22mand [1m.EE[22m.

       Optional  macro arguments are indicated by surrounding them with square
       brackets.  If a macro  accepts  multiple  arguments,  those  containing
       space characters must be double‐quoted to be interpreted correctly.  An
       empty  macro  argument  can  be  specified with a pair of double‐quotes
       (""), but the [4mman[24m package is designed such that this should  seldom  be
       necessary.   See section “Notes” below for examples of cases where bet‐
       ter alternatives to empty arguments in macro calls are available.  Most
       macro arguments will be formatted as text in the output; exceptions are
       noted.

   [1mDocument structure macros[0m
       Document structure macros organize a man page’s content.  All  of  them
       break  the output line.  [1m.TH [22m(title heading) identifies the document as
       a man page and configures the page headers and footers.  Section  head‐
       ings ([1m.SH[22m), one of which is mandatory and many of which are convention‐
       ally  expected,  facilitate  location of material by the reader and aid
       the man page writer to discuss all  essential  aspects  of  the  topic.
       Subsection  headings  ([1m.SS[22m)  are optional and permit sections that grow
       long to develop in a controlled way.  Many technical discussions  bene‐
       fit  from  examples; lengthy ones, especially those reflecting multiple
       lines of input to or output from the system, are usefully bracketed  by
       [1m.EX [22mand [1m.EE[22m.  When none of the foregoing meets a structural demand, use
       [1m.RS[22m/[1m.RE [22mto inset a region within a (sub)section.

       [1m.TH [4m[22mtopic[24m [4msection[24m [[4mfooter‐middle[24m] [[4mfooter‐inside[24m] [[4mheader‐middle[24m]
              Determine the contents of the page header and footer.  [4mroff[24m sys‐
              tems  refer  to  these collectively as “titles”.  The subject of
              the man page is [4mtopic[24m and the section of the manual to which  it
              belongs  is  [4msection.[24m   This  use of “section” has nothing to do
              with the section headings otherwise discussed in this  page;  it
              arises  from the organizational scheme of printed and bound Unix
              manuals.  See [4mman[24m(1) or [4mintro[24m(1) for the manual  sectioning  ap‐
              plicable  to  your system.  [4mtopic[24m and [4msection[24m are positioned to‐
              gether at the left and right in  the  header  (with  [4msection[24m  in
              parentheses  immediately  appended  to [4mtopic[24m).  [4mfooter‐middle[24m is
              centered in the footer.  The arrangement  of  the  rest  of  the
              footer  depends  on  whether double‐sided layout is enabled with
              the option [1m-rD1[22m.  When disabled (the default), [4mfooter‐inside[24m  is
              positioned at the bottom left.  Otherwise, [4mfooter‐inside[24m appears
              at  the  bottom  left  on recto (odd‐numbered) pages, and at the
              bottom right on verso (even‐numbered) pages.  The outside footer
              is the page number, except in the continuous‐rendering mode  en‐
              abled  by  the  option [1m-rcR=1[22m, in which case it is the [4mtopic[24m and
              [4msection,[24m as in the header.  [4mheader‐middle[24m  is  centered  in  the
              header.   If  [4msection[24m is an integer between 1 and 9 (inclusive),
              there is no need to specify [4mheader‐middle;[24m [4man.tmac[24m  will  supply
              text  for  it.   The macro package may also abbreviate [4mtopic[24m and
              [4mfooter‐inside[24m with ellipses ([1m...[22m)  if  they  would  overrun  the
              space  available  in  the  header and footer, respectively.  For
              HTML output, headers and footers are suppressed.

              Additionally, this macro breaks the page, resetting  the  number
              to  1  (unless  the  [1m-rC1 [22moption is given).  This feature is in‐
              tended only for formatting multiple [4mman[24m documents in sequence.

              A valid [4mman[24m document calls [1m.TH [22monce, early in the file, prior to
              any other macro calls.

              By convention, [4mfooter‐middle[24m is the date of the most recent mod‐
              ification to the man page source document, and [4mfooter‐inside[24m  is
              the name and version or release of the project providing it.

       [1m.SH [22m[[4mheading‐text[24m]
              Set [4mheading‐text[24m as a section heading.  If no argument is given,
              a  one‐line input trap is planted; text on the next line becomes
              [4mheading‐text.[24m  The left margin is reset to zero to set the head‐
              ing text in bold (or the font specified by the string [1mHF[22m),  and,
              on typesetting devices, slightly larger than the base type size.
              If  the  heading  font [1m\*[HF] [22mis bold, use of an italic style in
              [4mheading‐text[24m is mapped to the bold‐italic style if available  in
              the  font  family.   The  inset level is reset to 1, setting the
              left margin to the value of the [1mIN [22mregister.  Text  after  [4mhead‐[0m
              [4ming‐text[24m is set as an ordinary paragraph ([1m.P[22m).

              The  content  of [4mheading‐text[24m and ordering of sections follows a
              set of common practices, as has much of the layout  of  material
              within sections.  For example, a section called “Name” or “NAME”
              must  exist,  must  be the first section after the [1m.TH [22mcall, and
              must contain only text of the form
                     [4mtopic[24m[[1m, [4m[22manother‐topic[24m]... \- [4msummary‐description[0m
              for a man page to be properly indexed.  See [4mman[24m(7) for the  con‐
              ventions prevailing on your system.

       [1m.SS [22m[[4msubheading‐text[24m]
              Set  [4msubheading‐text[24m  as a subsection heading indented between a
              section heading and an ordinary paragraph ([1m.P[22m).  If no  argument
              is  given,  a  one‐line  input trap is planted; text on the next
              line becomes [4msubheading‐text.[24m  The left margin is reset  to  the
              value of the [1mSN [22mregister to set the heading text in bold (or the
              font specified by the string [1mHF[22m).  If the heading font [1m\*[HF] [22mis
              bold, use of an italic style in [4msubheading‐text[24m is mapped to the
              bold‐italic  style  if  available in the font family.  The inset
              level is reset to 1, setting the left margin to the value of the
              [1mIN [22mregister.  Text after [4msubheading‐text[24m is set as  an  ordinary
              paragraph ([1m.P[22m).

       [1m.EX[0m
       [1m.EE    [22mBegin  and  end  example.   After [1m.EX[22m, filling is disabled and a
              constant‐width (monospaced) font is selected.  Calling  [1m.EE  [22men‐
              ables filling and restores the previous font.

              Example  regions are useful for formatting code, shell sessions,
              and text file contents.  An example region  is  not  a  “literal
              mode” of any sort: special character escape sequences must still
              be  used to produce correct glyphs for [1m'[22m, [1m-[22m, [1m\[22m, [1m^[22m, [1m`[22m, and [1m~[22m, and
              sentence endings are still detected  and  additional  inter‐sen‐
              tence space applied.  If the amount of additional inter‐sentence
              spacing  is altered, the rendering of, for instance, regular ex‐
              pressions using [1m. [22mor [1m? [22mfollowed by multiple spaces  can  change.
              Use the dummy character escape sequence [1m\& [22mbefore the spaces.

              These macros are extensions introduced in Ninth Edition Research
              Unix.   Systems  running  that [4mtroff[24m, or those from Documenter’s
              Workbench, Heirloom Doctools, or Plan 9 [4mtroff[24m support them.   To
              be  certain  your  page will be portable to systems that do not,
              copy their definitions from the [4man-ext.tmac[24m file of a [4mgroff[24m  in‐
              stallation.

       [1m.RS [22m[[4minset‐amount[24m]
              Start a new relative inset level.  The position of the left mar‐
              gin  is  saved,  then moved right by [4minset‐amount,[24m if specified,
              and by the amount of the [1mIN [22mregister otherwise.   Calls  to  [1m.RS[0m
              can be nested; each increments by 1 the inset level used by [1m.RE[22m.
              The level prior to any [1m.RS [22mcalls is 1.

       [1m.RE [22m[[4mlevel[24m]
              End  a  relative  inset.  The left margin corresponding to inset
              level [4mlevel[24m is restored.  If no argument  is  given,  the  inset
              level is reduced by 1.

   [1mParagraphing macros[0m
       An  ordinary  paragraph  ([1m.P[22m) like this one is set without a first‐line
       indentation at the current left margin.  In man pages and other techni‐
       cal literature, definition lists are frequently encountered; these  can
       be set as “tagged paragraphs”, which have one ([1m.TP[22m) or more ([1m.TQ[22m) lead‐
       ing  tags  followed  by a paragraph that has an additional indentation.
       The indented paragraph ([1m.IP[22m) macro is useful to continue  the  indented
       content  of  a narrative started with [1m.TP[22m, or to present an itemized or
       ordered list.  All of these macros break the output line.   If  another
       paragraph  macro  has occurred since the previous [1m.SH [22mor [1m.SS[22m, they (ex‐
       cept for [1m.TQ[22m) follow the break with a default amount of vertical space,
       which can be changed by the deprecated [1m.PD [22mmacro; see subsection “Hori‐
       zontal and vertical spacing” below.  They also reset the type size  and
       font style to defaults ([1m.TQ [22magain excepted); see subsection “Font style
       macros” below.

       [1m.P[0m
       [1m.LP[0m
       [1m.PP    [22mBegin  a new paragraph; these macros are synonymous.  The inden‐
              tation is reset to the default value; the left  margin,  as  af‐
              fected by [1m.RS [22mand [1m.RE[22m, is not.

       [1m.TP [22m[[4mindentation[24m]
              Set  a  paragraph  with  a leading tag, and the remainder of the
              paragraph indented.  A one‐line input trap is planted;  text  on
              the  next line, which can be formatted with a macro, becomes the
              tag, which is placed at the current left margin.  The tag can be
              extended with the [1m\c [22mescape sequence.  Subsequent  text  is  in‐
              dented by [4mindentation,[24m if specified, and by the amount of the [1mIN[0m
              register  otherwise.   If the tag is not as wide as the indenta‐
              tion, the paragraph starts on the same line as the tag,  at  the
              applicable  indentation,  and  continues on the following lines.
              Otherwise, the descriptive part of the paragraph begins  on  the
              line following the tag.

              The  line  containing  the tag can include a macro call, for in‐
              stance to set the tag in bold with [1m.B[22m.  [1m.TP [22mwas  used  to  write
              the first paragraph of this description of [1m.TP[22m, and [1m.IP [22mthe sub‐
              sequent one.

       [1m.TQ    [22mSet an additional tag for a paragraph tagged with [1m.TP[22m.  An input
              trap is planted as with [1m.TP[22m.

              This  macro  is  a  GNU extension not defined on systems running
              AT&T, Plan 9, or  Solaris  [4mtroff[24m;  see  [4man-ext.tmac[24m  in  section
              “Files” below.

              The  descriptions  of  [1m.P[22m, [1m.LP[22m, and [1m.PP [22mabove were written using
              [1m.TP [22mand [1m.TQ[22m.

       [1m.IP [22m[[4mtag[24m] [[4mindentation[24m]
              Set an indented paragraph with an optional tag.  The [4mtag[24m and [4min‐[0m
              [4mdentation[24m arguments, if present, are handled as with  [1m.TP[22m,  with
              the  exception  that  the  [4mtag[24m  argument to [1m.IP [22mcannot include a
              macro call.

              Two convenient uses for [1m.IP [22mare

                  (1) to start a new paragraph with the same indentation as an
                      immediately preceding [1m.IP [22mor [1m.TP [22mparagraph, if no [4minden‐[0m
                      [4mtation[24m argument is given; and

                  (2) to set a paragraph with a short [4mtag[24m that is not semanti‐
                      cally important, such as a bullet (•)—obtained with  the
                      [1m\(bu  [22mspecial character escape sequence—or list enumera‐
                      tor, as seen in this very paragraph.

   [1mCommand synopsis macros[0m
       [1m.SY [22mand [1m.YS [22maid you to construct a command synopsis that has the  clas‐
       sical Unix appearance.  They break the output line.

       These  macros  are  GNU extensions not defined on systems running AT&T,
       Plan 9, or Solaris [4mtroff[24m; see [4man-ext.tmac[24m in section “Files” below.

       [1m.SY [4m[22mcommand[0m
              Begin synopsis.  A new paragraph begins at the left  margin  (as
              with  [1m.P[22m)  unless  [1m.SY  [22mhas already been called without a corre‐
              sponding [1m.YS[22m, in which case only a break is performed.   Adjust‐
              ment  and automatic hyphenation are disabled.  [4mcommand[24m is set in
              bold.  If a break is required, lines after  the  first  are  in‐
              dented by the width of [4mcommand[24m plus a space.

       [1m.YS    [22mEnd  synopsis.  Indentation, adjustment, and hyphenation are re‐
              stored to their previous states.

       Multiple [1m.SY[22m/[1m.YS [22mblocks can be specified, for instance  to  distinguish
       differing  modes  of  operation  of a complex command like [4mtar[24m(1); each
       will be vertically separated as paragraphs are.

       [1m.SY [22mcan be repeated before [1m.YS [22mto indicate synonymous ways of  invoking
       a particular mode of operation.

       [4mgroff[24m’s  own  command‐line  interface  serves to illustrate most of the
       specimens of synopsis syntax one is likely to encounter.

              .SY groff
              .RB [ \‐abcCeEgGijklNpRsStUVXzZ ]
              .RB [ \‐d\~\c
              .IR cs ]
              .RB [ \‐d\~\c
              .IB name =\c
              .IR string ]
              .RB [ \‐D\~\c
              .IR enc ]
              [4m(and[24m [4mso[24m [4mon[24m [4msimilarly)[0m
              .RI [ file\~ .\|.\|.]
              .YS
              .
              .
              .SY groff
              .B \‐h
              .
              .SY groff
              .B \‐\‐help
              .YS
              .
              .
              .SY groff
              .B \‐v
              .RI [ option\~ .\|.\|.\&]
              .RI [ file\~ .\|.\|.]
              .
              .SY groff
              .B \‐\‐version
              .RI [ option\~ .\|.\|.\&]
              .RI [ file\~ .\|.\|.]
              .YS

       produces the following output.

              [1mgroff [22m[[1m-abcCeEgGijklNpRsStUVXzZ[22m] [[1m-d [4m[22mcs[24m] [[1m-d [4m[22mname[24m[1m=[4m[22mstring[24m]
                    [[1m-D [4m[22menc[24m] [[1m-f [4m[22mfam[24m] [[1m-F [4m[22mdir[24m] [[1m-I [4m[22mdir[24m] [[1m-K [4m[22menc[24m] [[1m-L [4m[22marg[24m]
                    [[1m-m [4m[22mname[24m] [[1m-M [4m[22mdir[24m] [[1m-n [4m[22mnum[24m] [[1m-o [4m[22mlist[24m] [[1m-P [4m[22marg[24m] [[1m-r [4m[22mcn[24m]
                    [[1m-r [4m[22mreg[24m[1m=[4m[22mexpr[24m] [[1m-T [4m[22mdev[24m] [[1m-w [4m[22mname[24m] [[1m-W [4m[22mname[24m] [[4mfile[24m ...]

              [1mgroff -h[0m
              [1mgroff --help[0m

              [1mgroff -v [22m[[4moption[24m ...] [[4mfile[24m ...]
              [1mgroff --version [22m[[4moption[24m ...] [[4mfile[24m ...]

       Several features of the above example are of note.

       • The empty request (.), which does  nothing,  is  used  to  vertically
         space  the input file for readability by the document maintainer.  Do
         not put blank (empty) lines in a man page source document.

       • Command and option names are presented in [1mbold [22mto cue the  user  that
         they should be input literally.

       • Option  dashes  are specified with the [1m\- [22mescape sequence; this is an
         important practice to make them clearly  visible  and  to  facilitate
         copy‐and‐paste  from  the rendered man page to a shell prompt or text
         file.

       • Option arguments and command operands are presented in  [4mitalics[24m  (but
         see  subsection “Font style macros” below regarding terminals) to cue
         the user that they must be replaced with appropriate text.

       • Symbols that are neither to be typed literally nor  replaced  at  the
         user’s  discretion  appear  in the roman style; brackets surround op‐
         tional arguments, and an ellipsis indicates that the previous syntac‐
         tical element may be repeated arbitrarily.

       • The non‐breaking adjustable space escape sequence [1m\~ [22mis used to  pre‐
         vent  the  output  line from being broken within the option brackets;
         see subsection “Portability” below.

       • The output line continuation escape sequence [1m\c  [22mis  used  with  font
         style  alternation  macros  to  allow all three font styles to be set
         without (breakable) space among them;  see  subsection  “Portability”
         below.

       • The dummy character escape sequence [1m\& [22mfollows the ellipsis when fur‐
         ther  text  will  follow  after space on the output line, keeping its
         last period from being interpreted as the end of a sentence and caus‐
         ing additional inter‐sentence space to be placed after it.  See  sub‐
         section “Portability” below.

   [1mHyperlink macros[0m
       Man page cross references like [4mls[24m(1) are best presented with [1m.MR[22m.  Text
       may  be  hyperlinked to email addresses with [1m.MT[22m/[1m.ME [22mor other URIs with
       [1m.UR[22m/[1m.UE[22m.  Hyperlinked text is supported on HTML and terminal output de‐
       vices; terminals and pager programs must support ECMA‐48 OSC  8  escape
       sequences  (see [4mgrotty[24m(1)).  When device support is unavailable or dis‐
       abled with the [1mU [22mregister (see section “Options” below),  [1m.MT  [22mand  [1m.UR[0m
       URIs are rendered between angle brackets after the linked text.

       [1m.MT[22m,  [1m.ME[22m,  [1m.UR[22m, and [1m.UE [22mare GNU extensions not defined on systems run‐
       ning AT&T, Plan 9, or Solaris [4mtroff[24m; see [4man-ext.tmac[24m in section “Files”
       below.  Plan 9 from User Space’s [4mtroff[24m implements [1m.MR[22m.

       The arguments to [1m.MR[22m, [1m.MT[22m, and [1m.UR [22mshould be prepared  for  typesetting
       since  they can appear in the output.  Use special character escape se‐
       quences to encode Unicode basic Latin characters where necessary,  par‐
       ticularly  the  hyphen‐minus.  (See section “Portability” below.)  URIs
       can be lengthy; rendering them can  result  in  jarring  adjustment  or
       variations in line length, or [4mtroff[24m warnings when a hyperlink is longer
       than  an  output line.  The application of non‐printing break point es‐
       cape sequences [1m\: [22mafter each slash (or series thereof), and before each
       dot (or series thereof) is recommended as a rule of thumb.  The  former
       practice  avoids forcing a trailing slash in a URI onto a separate out‐
       put line, and the latter helps the reader to  avoid  mistakenly  inter‐
       preting  a dot at the end of a line as a period (or multiple dots as an
       ellipsis).  Thus,
              .UR http://\:example\:.com/\:fb8afcfbaebc74e\:.cc
       has several potential break points in the URI shown.   Consider  adding
       break  points before or after at signs in email addresses, and question
       marks, ampersands, and number signs in HTTP(S) URIs.  The formatter re‐
       moves [1m\: [22mescape sequences from hyperlinks when supplying device control
       commands to output drivers.

       [1m.MR [4m[22mtopic[24m [4mmanual‐section[24m [[4mtrailing‐text[24m]
              [4m(since[24m groff [4m1.23)[24m Set a man page cross reference as “[4mtopic[24m[1m([4m[22mman‐[0m
              [4mual‐section[24m[1m)[22m”.   If  [4mtrailing‐text[24m  (typically  punctuation)  is
              specified,  it follows the closing parenthesis without interven‐
              ing space.  Hyphenation is disabled while the cross reference is
              set.  [4mtopic[24m is set in the font specified by the [1mMF [22mstring.   The
              cross  reference hyperlinks to a URI of the form “[1mman:[4m[22mtopic[24m([4mman‐[0m
              [4mual‐section[24m)”.

                     The output driver
                     .MR grops 1
                     produces PostScript from
                     .I troff
                     output.
                     .
                     The Ghostscript program (\c
                     .MR gs 1 )
                     interprets PostScript and PDF.

       [1m.MT [4m[22maddress[0m
       [1m.ME [22m[[4mtrailing‐text[24m]
              Identify [4maddress[24m as an RFC 6068 [4maddr‐spec[24m for  a  “mailto:”  URI
              with  the text between the two macro calls as the link text.  An
              argument to [1m.ME [22mis placed after the link text without  interven‐
              ing  space.  [4maddress[24m may not be visible in the rendered document
              if hyperlinks are enabled and supported by  the  output  driver.
              If they are not, [4maddress[24m is set in angle brackets after the link
              text  and  before [4mtrailing‐text.[24m  If hyperlinking is enabled but
              there is no link text,  [4maddress[24m  is  formatted  and  hyperlinked
              [4mwithout[24m angle brackets.

              When rendered by [4mgroff[24m to a PostScript device,

                     Contact
                     .MT fred\:.foonly@\:fubar\:.net
                     Fred Foonly
                     .ME
                     for more information.

              displays  as  “Contact  Fred  Foonly ⟨fred.foonly@fubar.net⟩ for
              more information.”.

       [1m.UR [4m[22muri[0m
       [1m.UE [22m[[4mtrailing‐text[24m]
              Identify [4muri[24m as an RFC 3986 URI hyperlink with the text  between
              the  two  macro  calls  as the link text.  An argument to [1m.UE [22mis
              placed after the link text without intervening space.   [4muri[24m  may
              not  be  visible  in the rendered document if hyperlinks are en‐
              abled and supported by the output driver.  If they are not,  [4muri[0m
              is  set  in angle brackets after the link text and before [4mtrail‐[0m
              [4ming‐text.[24m  If hyperlinking is enabled but there is no link text,
              [4muri[24m is formatted and hyperlinked [4mwithout[24m angle brackets.

              When rendered by [4mgroff[24m to a PostScript device,

                     The GNU Project of the Free Software Foundation
                     hosts the
                     .UR https://\:www\:.gnu\:.org/\:software/\:groff/
                     .I groff
                     home page
                     .UE .

              displays as “The GNU Project of  the  Free  Software  Foundation
              hosts   the   [4mgroff[24m   home  page  ⟨https://www.gnu.org/software/
              groff/⟩.”.

       The hyperlinking of [1m.TP [22mparagraph tags with [1m.UR[22m/[1m.UE [22mand [1m.MT[22m/[1m.ME [22mis  not
       yet  supported;  if attempted, the hyperlink will be typeset at the be‐
       ginning of the indented paragraph even on hyperlink‐supporting devices.

   [1mFont style macros[0m
       The [4mman[24m macro package is limited in its font styling options,  offering
       only [1mbold [22m([1m.B[22m), [4mitalic[24m ([1m.I[22m), and roman.  Italic text is usually set un‐
       derscored instead on terminal devices.  The [1m.SM [22mand [1m.SB [22mmacros set text
       in  roman  or  bold, respectively, at a smaller type size; these differ
       visually from regular‐sized roman or bold text only on typesetting  de‐
       vices.   It  is often necessary to set text in different styles without
       intervening space.  The macros [1m.BI[22m, [1m.BR[22m, [1m.IB[22m, [1m.IR[22m, [1m.RB[22m, and [1m.RI[22m,  where
       “B”,  “I”,  and “R” indicate bold, italic, and roman, respectively, set
       their odd‐ and even‐numbered arguments in alternating styles,  with  no
       space separating them.

       Because  font styles are presentational rather than semantic, conflict‐
       ing traditions have arisen regarding which font styles should  be  used
       to  mark  file or path names, environment variables, and inlined liter‐
       als.

       The default type size and family for typesetting  devices  is  10‐point
       Times,  except on the [1mX75-12 [22mand [1mX100-12 [22mdevices where the type size is
       12 points.  The default style is roman.

       [1m.B [22m[[4mtext[24m]
              Set [4mtext[24m in bold.  If no argument is  given,  a  one‐line  input
              trap  is  planted;  text  on the next line, which can be further
              formatted with a macro, is set in bold.

              Use bold for literal portions of syntax synopses,  for  command‐
              line  options  in  running text, and for literals that are major
              topics of the subject under discussion; for example,  this  page
              uses  bold for macro, string, and register names.  In an [1m.EX[22m/[1m.EE[0m
              example of interactive I/O (such as a shell session),  set  only
              user input in bold.

       [1m.I [22m[[4mtext[24m]
              Set [4mtext[24m in an italic or oblique face.  If no argument is given,
              a  one‐line  input trap is planted; text on the next line, which
              can be further formatted with a macro, is set in  an  italic  or
              oblique face.

              Use  italics for file and path names, for environment variables,
              for C data types, for enumeration or preprocessor  constants  in
              C,  for  variant (user‐replaceable) portions of syntax synopses,
              for the first occurrence (only) of a technical concept being in‐
              troduced, for names of journals and  of  literary  works  longer
              than  an article, and anywhere a parameter requiring replacement
              by the user is encountered.  An exception involves variant  text
              in  a  context  already typeset in italics, such as file or path
              names with replaceable components; in  such  cases,  follow  the
              convention of mathematical typography: set the file or path name
              in  italics as usual but use roman for the variant part (see [1m.IR[0m
              and [1m.RI [22mbelow), and italics again in running roman text when re‐
              ferring to the variant material.

       [1m.SM [22m[[4mtext[24m]
              Set [4mtext[24m one point smaller than the default type size  on  type‐
              setting devices.  If no argument is given, a one‐line input trap
              is  planted; text on the next line, which can be further format‐
              ted with a macro, is set smaller.

              [4mNote:[24m terminals will render [4mtext[24m at normal size instead.  Do not
              rely upon [1m.SM [22mto communicate semantic information distinct  from
              using roman style at normal size; it will be hidden from readers
              using such devices.

       [1m.SB [22m[[4mtext[24m]
              Set  [4mtext[24m in bold and (on typesetting devices) one point smaller
              than the default type size.  If no argument is given, a one‐line
              input trap is planted; text on the next line, which can be  fur‐
              ther  formatted  with a macro, is set smaller and in bold.  This
              macro is an extension introduced in SunOS 4.0.

              [4mNote:[24m terminals will render [4mtext[24m in bold at the normal size  in‐
              stead.  Do not rely upon [1m.SB [22mto communicate semantic information
              distinct from using bold style at normal size; it will be hidden
              from readers using such devices.

       Observe  what  is  [4mnot[24m prescribed for setting in bold or italics above:
       elements of “synopsis language” such as ellipses  and  brackets  around
       options; proper names and adjectives; titles of anything other than ma‐
       jor works of literature; identifiers for standards documents or techni‐
       cal  reports such as CSTR #54, RFC 1918, Unicode 13.0, or POSIX.1‐2017;
       acronyms; and occurrences after the first of a technical term.

       Be frugal with italics for emphasis, and particularly with bold.  Arti‐
       cle titles and brief runs of literal text, such as references to  indi‐
       vidual  characters  or  short strings, including section and subsection
       headings of man pages, are suitable  objects  for  quotation;  see  the
       [1m\(lq[22m, [1m\(rq[22m, [1m\(oq[22m, and [1m\(cq [22mescape sequences in subsection “Portability”
       below.

       Unlike  the  above font style macros, the font style alternation macros
       below set no input traps; they must be given arguments to have  effect.
       Italic  corrections are applied as appropriate.  If a space is required
       within an argument, first consider whether the  same  result  could  be
       achieved  with as much clarity by using single‐style macros on separate
       input lines.  When it cannot, double‐quote an argument  containing  em‐
       bedded  space  characters.  Setting all three different styles within a
       word presents challenges; it is possible with the [1m\c [22mand/or  [1m\f  [22mescape
       sequences.  See subsection “Portability” below for approaches.

       [1m.BI [4m[22mbold‐text[24m [4mitalic‐text[24m ...
              Set each argument in bold and italics, alternately.

                     .BI -r  register = numeric‐expression

       [1m.BR [4m[22mbold‐text[24m [4mroman‐text[24m ...
              Set each argument in bold and roman, alternately.

                     After
                     .B .NH
                     is called,

       [1m.IB [4m[22mitalic‐text[24m [4mbold‐text[24m ...
              Set each argument in italics and bold, alternately.

                     In places where
                     .IB n th
                     is allowed,

       [1m.IR [4m[22mitalic‐text[24m [4mroman‐text[24m ...
              Set each argument in italics and roman, alternately.

                     Use GNU
                     .IR pic 's
                     .B figname
                     command to change the name of the vbox.

       [1m.RB [4m[22mroman‐text[24m [4mbold‐text[24m ...
              Set each argument in roman and bold, alternately.

                     if
                     .I file
                     is
                     .RB \[lq] \- \[rq],
                     the standard input stream is read.

       [1m.RI [4m[22mroman‐text[24m [4mitalic‐text[24m ...
              Set each argument in roman and italics, alternately.

                     .RI ( tpic
                     was a fork of AT&T
                     .I pic
                     by Tim Morgan of the University of California at Irvine

   [1mHorizontal and vertical spacing[0m
       The  [4mindentation[24m  argument accepted by [1m.IP[22m, [1m.TP[22m, and the deprecated [1m.HP[0m
       is a number plus an optional scaling unit, as  is  [1m.RS[22m’s  [4minset‐amount[24m.
       If  no scaling unit is given, the [4mman[24m package assumes “n”; that is, the
       width of a letter “n” in the font current when the macro is called (see
       section “Measurements” in [4mgroff[24m(7)).  An  indentation  specified  in  a
       call  to  [1m.IP[22m, [1m.TP[22m, or the deprecated [1m.HP [22mpersists until (1) another of
       these macros is called with an [4mindentation[24m argument, or (2)  [1m.SH[22m,  [1m.SS[22m,
       or [1m.P [22mor its synonyms is called; these clear the indentation entirely.

       The  left  margin used by ordinary paragraphs set with [1m.P [22m(and its syn‐
       onyms) not within an [1m.RS[22m/[1m.RE [22mrelative inset is 7.2n for typesetting de‐
       vices and 7n for terminal devices (but see the [1m-rIN [22moption).   Headers,
       footers  (both set with [1m.TH[22m), and section headings ([1m.SH[22m) are set at the
       page offset (see [4mgroff[24m(7)) and subsection headings ([1m.SS[22m) indented  from
       it by 3n (but see the [1m-rSN [22moption).

       It  may  be  helpful to think of the left margin and indentation as re‐
       lated but distinct concepts; [4mgroff[24m’s implementation of  the  [4mman[24m  macro
       package  tracks them separately.  The left margin is manipulated by [1m.RS[0m
       and [1m.RE [22m(and by [1m.SH [22mand [1m.SS[22m, which reset it to the default).   Indenta‐
       tion  is  controlled by the paragraphing macros (though, again, [1m.SH [22mand
       [1m.SS [22mreset it); it is imposed  by  the  [1m.TP[22m,  [1m.IP[22m,  and  deprecated  [1m.HP[0m
       macros,  and  cancelled  by  [1m.P [22mand its synonyms.  An extensive example
       follows.

       This ordinary ([1m.P[22m) paragraph is not in a relative  inset  nor  does  it
       possess an indentation.

              Now  we have created a relative inset (in other words, moved the
              left margin) with [1m.RS [22mand  started  another  ordinary  paragraph
              with [1m.P[22m.

              [1mtag    [22mThis  tagged paragraph, set with [1m.TP[22m, is still within the
                     [1m.RS [22mregion, but lines after the first have  a  supplemen‐
                     tary indentation that the tag lacks.

                     A  paragraph  like this one, set with [1m.IP[22m, will appear to
                     the reader as also associated with the tag above, because
                     [1m.IP [22mre‐uses the previous paragraph’s  indentation  unless
                     given  an  argument  to change it.  This paragraph is af‐
                     fected both by the moved left margin ([1m.RS[22m)  and  indenta‐
                     tion ([1m.IP[22m).
                     ┌──────────────────────────────────┐
                     │ This table is affected both by   │
                     │ the left margin and indentation. │
                     └──────────────────────────────────┘

              •      This indented paragraph has a bullet for a tag, making it
                     more  obvious  that  the  left margin and indentation are
                     distinct; only the former affects the tag, but  both  af‐
                     fect the text of the paragraph.

              This  ordinary  ([1m.P[22m)  paragraph  resets the indentation, but the
              left margin is still inset.
              ┌─────────────────────────────┐
              │ This table is affected only │
              │ by the left margin.         │
              └─────────────────────────────┘

       Finally, we have ended the relative inset by using [1m.RE[22m, which  (because
       we  used  only  one  [1m.RS[22m/[1m.RE [22mpair) has reset the left margin to the de‐
       fault.  This is an ordinary [1m.P [22mparagraph.

       Resist the temptation to mock up tabular or  multi‐column  output  with
       tab  characters  or  the indentation arguments to [1m.IP[22m, [1m.TP[22m, [1m.RS[22m, or the
       deprecated [1m.HP[22m; the result may not render comprehensibly on  an  output
       device you fail to check, or which is developed in the future.  The ta‐
       ble preprocessor [4mtbl[24m(1) can likely meet your needs.

       Several  macros  insert vertical space: [1m.SH[22m, [1m.SS[22m, [1m.TP[22m, [1m.P [22m(and its syn‐
       onyms), [1m.IP[22m, and the deprecated [1m.HP[22m.  The default inter‐section and in‐
       ter‐paragraph spacing is is 1v for terminal devices and 0.4v for  type‐
       setting  devices  (“v”  is a unit of vertical distance, where 1v is the
       distance between adjacent text baselines in a single‐spaced  document).
       (The deprecated macro [1m.PD [22mcan change this vertical spacing, but its use
       is  discouraged.)  Between [1m.EX [22mand [1m.EE [22mcalls, the inter‐paragraph spac‐
       ing is 1v regardless of output device.

   [1mRegisters[0m
       Registers are described in section “Options” below.  They  can  be  set
       not  only  on  the command line but in the site [4mman.local[24m file as well;
       see section “Files” below.

   [1mStrings[0m
       The following strings are defined for use in  man  pages.   Others  are
       supported  for  configuration of rendering parameters; see section “Op‐
       tions” below.

       [1m\*R    [22minterpolates a special character escape sequence for the “regis‐
              tered sign” glyph, [1m\(rg[22m, if available, and “(Reg.)” otherwise.

       [1m\*S    [22minterpolates an escape sequence setting the  type  size  to  the
              document default.

       [1m\*(lq[0m
       [1m\*(rq  [22minterpolate  special  character  escape  sequences  for left and
              right double‐quotation marks, [1m\(lq [22mand [1m\(rq[22m, respectively.

       [1m\*(Tm  [22minterpolates a special character escape sequence for the  “trade
              mark sign” glyph, [1m\(tm[22m, if available, and “(TM)” otherwise.

       None  of the above is necessary in a contemporary man page.  [1m\*S [22mis su‐
       perfluous, since type size changes are invisible  on  terminal  devices
       and macros that change it restore its original value afterward.  Better
       alternatives  exist  for the rest; simply use the [1m\(rg[22m, [1m\(lq[22m, [1m\(rq[22m, and
       [1m\(tm [22mspecial character escape sequences directly.  Unless  a  man  page
       author  is  aiming for a pathological level of portability, such as the
       composition of pages for consumption on simulators of 1980s  Unix  sys‐
       tems  (or  Solaris  [4mtroff[24m,  though  even  it  supports [1m\(rg[22m), the above
       strings should be avoided.

   [1mPortability[0m
       It is wise to quote multi‐word section and subsection headings; the [1m.SH[0m
       and [1m.SS [22mmacros of [4mman[24m(7) implementations descended from Seventh Edition
       Unix supported six arguments at most.  A similar restriction applied to
       the [1m.B[22m, [1m.I[22m, [1m.SM[22m, and font style alternation macros.

       The two major syntactical categories for formatting control in the [4mroff[0m
       language are requests and escape sequences.  Since the [4mman[24m  macros  are
       implemented  in  terms of [4mgroff[24m requests and escape sequences, one can,
       in principle, supplement the functionality of  [4mman[24m  with  these  lower‐
       level elements where necessary.

       However, using raw [4mgroff[24m requests (apart from the empty request “[1m.[22m”) is
       likely  to  make your page render poorly when processed by other tools;
       many of these attempt to interpret page sources directly for conversion
       to HTML.  Some requests make implicit  assumptions  about  things  like
       character  and  page  sizes  that  may not hold in an HTML environment;
       also, many of these viewers don’t interpret the full [4mgroff[24m  vocabulary,
       a  problem that can lead to portions of your text being omitted or pre‐
       sented incomprehensibly.

       For portability to modern viewers, it is best to write your page solely
       with the macros described in this page (except for the ones  identified
       as  deprecated, which should be avoided).  The macros we have described
       as extensions ([1m.EX[22m/[1m.EE[22m, [1m.SY[22m/[1m.YS[22m, [1m.TQ[22m, [1m.UR[22m/[1m.UE[22m, [1m.MT[22m/[1m.ME[22m, [1m.MR[22m,  and  [1m.SB[22m)
       should be used with caution, as they may not be built in to some viewer
       that is important to your audience.  See [4man-ext.tmac[24m in section “Files”
       below.

       Similar  caveats  apply to escape sequences.  Some escape sequences are
       however required for correct typesetting even in man pages and  usually
       do not cause portability problems.  Several of these render glyphs cor‐
       responding  to punctuation code points in the Unicode basic Latin range
       (U+0000–U+007F) that are handled specially in [4mroff[24m  input;  the  escape
       sequences below must be used to render them correctly and portably when
       documenting  material  that  uses them syntactically—namely, any of the
       set [1m' - \ ^ ` ~ [22m(apostrophe, dash or minus, backslash, caret, grave ac‐
       cent, tilde).

       [1m\"     [22mComment.  Everything after the double‐quote to the  end  of  the
              input line is ignored.  Whole‐line comments should be placed im‐
              mediately after the empty request (“[1m.[22m”).

       [1m\[4m[22mnewline[0m
              Join the next input line to the current one.  Except for the up‐
              date of the input line counter (used for diagnostic messages and
              related purposes), a series of lines ending in backslash‐newline
              appears  to  [4mgroff[24m  as a single input line.  Use this escape se‐
              quence to split excessively long input lines for document  main‐
              tenance.

       [1m\%     [22mControl  hyphenation.   The  location  of  this  escape sequence
              within a word marks a hyphenation point,  supplementing  [4mgroff[24m’s
              automatic  hyphenation patterns.  At the beginning of a word, it
              suppresses any hyphenation breaks within [4mexcept[24m those  specified
              with [1m\%[22m.

       [1m\:     [22mInsert  a  non‐printing break point.  A word can break at such a
              point, but a hyphen glyph is not written to  the  output  if  it
              does.   This  escape  sequence is an input word boundary, so the
              remainder of the word is subject to hyphenation as normal.   You
              can  use  [1m\: [22mand [1m\% [22min combination to control breaking of a file
              name or URI or to permit hyphenation only after certain explicit
              hyphens within a word.  See subsection “Hyperlink macros”  above
              for an example.

              This  escape  sequence  is  a  [4mgroff[24m extension also supported by
              Heirloom Doctools [4mtroff[24m 050915 (September 2005),  [4mmandoc[24m  1.14.5
              (2019‐03‐10),  and  [4mneatroff[24m  (commit 399a4936, 2014‐02‐17), but
              not by Plan 9, Solaris, or Documenter’s Workbench [4mtroff[24ms.

       [1m\~     [22mAdjustable non‐breaking space.  Use this escape sequence to pre‐
              vent a break inside a short phrase or between a numerical  quan‐
              tity and its corresponding unit(s).

                     Before starting the motor,
                     set the output speed to\~1.
                     There are 1,024\~bytes in 1\~KiB.
                     CSTR\~#8 documents the B\~language.

              This  escape  sequence  is  a  [4mgroff[24m extension also supported by
              Heirloom Doctools [4mtroff[24m 050915 (September  2005),  [4mmandoc[24m  1.9.5
              (2009‐09‐21),   [4mneatroff[24m  (commit  1c6ab0f6e,  2016‐09‐13),  and
              Plan 9 from User Space [4mtroff[24m  (commit  93f8143600,  2022‐08‐12),
              but not by Solaris or Documenter’s Workbench [4mtroff[24ms.

       [1m\&     [22mDummy  character.   Insert  at the beginning of an input line to
              prevent a dot or apostrophe from being interpreted as  beginning
              a  [4mroff[24m  control line.  Append to an end‐of‐sentence punctuation
              sequence to keep it from being recognized as such.

       [1m\|     [22mThin space (one‐sixth em on typesetters,  zero‐width  on  termi‐
              nals);   a  non‐breaking  space.   Used  primarily  in  ellipses
              (“.\|.\|.”)  to space the dots more  pleasantly  on  typesetting
              devices like [1mdvi[22m, [1mpdf[22m, and [1mps[22m.

       [1m\c     [22mEnd  a  text line without inserting space or attempting a break.
              Normally, if filling is enabled, the  end  of  a  text  line  is
              treated  like  a  space;  an output line [4mmay[24m be broken there (if
              not, an adjustable space is inserted); if filling  is  disabled,
              the line [4mwill[24m be broken there, as in [1m.EX[22m/[1m.EE [22mexamples.  The next
              line  is interpreted as usual and can include a macro call (con‐
              trast with [1m\[4m[22mnewline[24m).  [1m\c [22mis useful when three font  styles  are
              needed in a single word, as in a command synopsis.

                     .RB [ \-\-stylesheet=\c
                     .IR name ]

              It  also  helps  when  changing font styles in [1m.EX[22m/[1m.EE [22mexamples,
              since they are not filled.

                     .EX
                     $ \c
                     .B groff \-T utf8 \-Z \c
                     .I file \c
                     .B | grotty \-i
                     .EE

              Alternatively, and perhaps with better portability, the [1m\f  [22mfont
              selection  escape  sequence can be used; see below.  Using [1m\c [22mto
              continue a [1m.TP [22mparagraph tag across multiple  input  lines  will
              render  incorrectly with [4mgroff[24m 1.22.3, [4mmandoc[24m 1.14.1, older ver‐
              sions of these programs, and perhaps with some other formatters.

       [1m\e     [22mFormat the current escape character on the output;  widely  used
              in  man pages to render a backslash glyph.  It works reliably as
              long as the “.ec” request is not used, which should never happen
              in man pages, and it is slightly more portable than the more ex‐
              plicit [1m\(rs [22m(“reverse solidus”)  special  character  escape  se‐
              quence.

       [1m\fB[22m, [1m\fI[22m, [1m\fR[22m, [1m\fP[0m
              Switch  to  bold,  italic, roman, or back to the previous style,
              respectively.  Either [1m\f [22mor [1m\c [22mis needed  when  three  different
              font styles are required in a word.

                     .RB [ \-\-reference\-dictionary=\fI\,name\/\fP ]

                     .RB [ \-\-reference\-dictionary=\c
                     .IR name ]

              Style  escape  sequences may be more portable than [1m\c[22m.  As shown
              above, it is up to you to account for  italic  corrections  with
              “[1m\/[22m”  and  “[1m\,[22m”, which are themselves GNU extensions, if desired
              and if supported by your implementation.

              [1m\fP [22mreliably returns to the style in use  immediately  preceding
              the  previous  [1m\f  [22mescape  sequence only if no sectioning, para‐
              graph, or style macro calls have intervened.

              As long as at most two styles are needed in a word, style macros
              like [1m.B [22mand [1m.BI [22musually result in more readable [4mroff[24m source than
              [1m\f [22mescape sequences do.

       Several special characters are also widely portable.   Except  for  [1m\-[22m,
       [1m\(em[22m,  and  [1m\(ga[22m, AT&T [4mtroff[24m did not consistently define the characters
       listed below, but its descendants, like Plan 9 or Solaris [4mtroff[24m, can be
       made to support them by defining them in font description files, making
       them aliases of existing glyphs if necessary; see [4mgroff_font[24m(5).

       [1m\-     [22mMinus sign or basic Latin hyphen‐minus.   This  escape  sequence
              produces  the  Unix command‐line option dash in the output.  “[1m-[22m”
              is a hyphen in the [4mroff[24m language; some output devices replace it
              with U+2010 (hyphen) or similar.

       [1m\(aq   [22mBasic Latin neutral apostrophe.  Some output devices format  “[1m'[22m”
              as a right single quotation mark.

       [1m\(oq[0m
       [1m\(cq   [22mOpening  (left) and closing (right) single quotation marks.  Use
              these for paired directional single quotes, ‘like this’.

       [1m\(dq   [22mBasic Latin quotation mark (double quote).  Use in  macro  calls
              to  prevent ‘[1m"[22m” from being interpreted as beginning a quoted ar‐
              gument, or simply for readability.

                     .TP
                     .BI "split \(dq" text \(dq

       [1m\(lq[0m
       [1m\(rq   [22mLeft and right double quotation marks.  Use these for paired di‐
              rectional double quotes, “like this”.

       [1m\(em   [22mEm‐dash.  Use for an interruption—such as  this  one—in  a  sen‐
              tence.

       [1m\(en   [22mEn‐dash.   Use to separate the ends of a range, particularly be‐
              tween numbers; for example, “the digits 1–9”.

       [1m\(ga   [22mBasic Latin grave accent.  Some output devices format “[1m`[22m”  as  a
              left single quotation mark.

       [1m\(ha   [22mBasic Latin circumflex accent (“hat”).  Some output devices for‐
              mat  “[1m^[22m”  as U+02C6 (modifier letter circumflex accent) or simi‐
              lar.

       [1m\(rs   [22mReverse solidus (backslash).  The backslash is the  default  es‐
              cape  character  in  the [4mroff[24m language, so it does not represent
              itself in output.  Also see [1m\e [22mabove.

       [1m\(ti   [22mBasic Latin tilde.  Some output devices  format  “[1m~[22m”  as  U+02DC
              (small tilde) or similar.

       For  maximum  portability,  escape sequences and special characters not
       listed above are better avoided in man pages.

   [1mHooks[0m
       Two macros, both GNU extensions, are called internally by the [4mgroff[24m [4mman[0m
       package to format page headers and footers and can be redefined by  the
       administrator  in  a site’s [4mman.local[24m file (see section “Files” below).
       The presentation of [1m.TH [22mabove describes the default headers  and  foot‐
       ers.  Because these macros are hooks for [4mgroff[24m [4mman[24m internals, man pages
       have no reason to call them.  Such hook definitions will likely consist
       of  “.sp”  and “.tl” requests.  They must also increase the page length
       with “.pl” requests in continuous rendering mode; [1m.PT  [22mfurthermore  has
       the  responsibility  of emitting a PDF bookmark after writing the first
       page header in a document.  Consult  the  existing  implementations  in
       [4man.tmac[24m when drafting replacements.

       [1m.BT    [22mSet the page footer text (“bottom trap”).

       [1m.PT    [22mSet the page header text (“page trap”).

       To  remove  a  page  header  or footer entirely, define the appropriate
       macro as empty rather than deleting it.

   [1mDeprecated features[0m
       Use of the following in man pages for public distribution  is  discour‐
       aged.

       [1m.AT [22m[[4msystem[24m [[4mrelease[24m]]
              Alter  the footer for use with legacy AT&T man pages, overriding
              any definition of the [4mfooter‐inside[24m argument to [1m.TH[22m.  This macro
              exists only to render man pages from historical systems.

              [4msystem[24m can be any of the following.

                     3      7th edition [4m(default)[0m

                     4      System III

                     5      System V

              The optional [4mrelease[24m argument specifies the release  number,  as
              in “System V Release 3”.

       [1m.DT    [22mReset tab stops to the default (every 0.5i [inches]).

              Use  of  this  presentation‐oriented  macro  is  deprecated.  It
              translates poorly to HTML, under which exact space  control  and
              tabulation are not readily available.  Thus, information or dis‐
              tinctions  that  you  use  tab stops to express are likely to be
              lost.  If you feel tempted to change the  tab  stops  such  that
              calling  this  macro  later  is  desirable  to restore them, you
              should probably be composing a table using [4mtbl[24m(1) instead.

       [1m.HP [22m[[4mindentation[24m]
              Set up a paragraph with a hanging left indentation.  The  [4minden‐[0m
              [4mtation[24m argument, if present, is handled as with [1m.TP[22m.

              Use  of this presentation‐oriented macro is deprecated.  A hang‐
              ing indentation cannot be expressed naturally  under  HTML,  and
              non‐[4mroff[24m‐based  man  page interpreters may treat [1m.HP [22mas an ordi‐
              nary paragraph.  Thus, information or distinctions you  mean  to
              express with indentation may be lost.

       [1m.OP [4m[22moption‐name[24m [[4moption‐argument[24m]
              Indicate an optional command parameter called [4moption‐name[24m, which
              is  set  in  bold.  If the option takes an argument, specify [4mop‐[0m
              [4mtion‐argument[24m using a noun,  abbreviation,  or  hyphenated  noun
              phrase.   If present, [4moption‐argument[24m is preceded by a space and
              set in italics.  Square brackets in roman  surround  both  argu‐
              ments.

              Use  of  this  quasi‐semantic macro, an extension originating in
              Documenter’s Workbench [4mtroff[24m, is deprecated.  It  cannot  easily
              be  used to annotate options that take optional arguments or op‐
              tions whose arguments have internal structure (such as a mixture
              of literal and variable  components).   One  could  work  around
              these  limitations  with font selection escape sequences, but it
              is preferable to use font style alternation macros, which afford
              greater flexibility.

       [1m.PD [22m[[4mvertical‐space[24m]
              Define the vertical space between paragraphs  or  (sub)sections.
              The  optional  argument [4mvertical‐space[24m specifies the amount; the
              default scaling unit is “v”.  Without an argument,  the  spacing
              is  reset  to  its default value; see subsection “Horizontal and
              vertical spacing” above.

              Use of  this  presentation‐oriented  macro  is  deprecated.   It
              translates  poorly  to HTML, under which exact control of inter‐
              paragraph spacing is not readily available.   Thus,  information
              or  distinctions  that  you  use [1m.PD [22mto express are likely to be
              lost.

       [1m.UC [22m[[4mversion[24m]
              Alter the footer for use with legacy BSD man  pages,  overriding
              any definition of the [4mfooter‐inside[24m argument to [1m.TH[22m.  This macro
              exists only to render man pages from historical systems.

              [4mversion[24m can be any of the following.

                     3      3rd Berkeley Distribution [4m(default)[0m

                     4      4th Berkeley Distribution

                     5      4.2 Berkeley Distribution

                     6      4.3 Berkeley Distribution

                     7      4.4 Berkeley Distribution

   [1mHistory[0m
       M.  Douglas  McIlroy ⟨m.douglas.mcilroy@dartmouth.edu⟩ designed, imple‐
       mented, and documented the AT&T [4mman[24m macros for Unix  Version  7  (1979)
       and  employed them to edit the first volume of its [4mProgrammer’s[24m [4mManual[24m,
       a compilation of all man pages supplied by the system.  That  [4mman[24m  sup‐
       ported  the macros listed in this page not described as extensions, ex‐
       cept [1m.P [22mand the deprecated [1m.AT [22mand [1m.UC[22m.  The only strings defined  were
       [1mR [22mand [1mS[22m; no registers were documented.

       [1m.UC  [22mappeared in 3BSD (1980).  Unix System III (1980) introduced [1m.P [22mand
       exposed the registers [1mIN [22mand [1mLL[22m, which had  been  internal  to  Seventh
       Edition  Unix  [4mman[24m.   PWB/UNIX  2.0  (1980)  added the [1mTm [22mstring.  4BSD
       (1980) added [1mlq [22mand [1mrq [22mstrings.  SunOS 2.0 (1985) recognized [1mC[22m,  [1mD[22m,  [1mP[22m,
       and  [1mX  [22mregisters.   4.3BSD (1986) added [1m.AT [22mand [1m.P[22m.  Ninth Edition Re‐
       search Unix (1986) introduced [1m.EX [22mand [1m.EE[22m.  SunOS 4.0 (1988) added [1m.SB[22m.

       The foregoing features were what James Clark implemented in early  ver‐
       sions  of  [4mgroff[24m.   Later,  [4mgroff[24m  1.20 (2009) originated [1m.SY[22m/[1m.YS[22m, [1m.TQ[22m,
       [1m.MT[22m/[1m.ME[22m, and [1m.UR[22m/[1m.UE[22m.  Plan 9 from User Space’s [4mtroff[24m introduced [1m.MR [22min
       2020.

[1mOptions[0m
       The following [4mgroff[24m options set registers (with [1m-r[22m) and  strings  (with
       [1m-d[22m)  recognized and used by the [4mman[24m macro package.  To ensure rendering
       consistent with output device capabilities and reader preferences,  man
       pages should never manipulate them.

       [1m-dAD=[4m[22madjustment‐mode[0m
              Set  line  adjustment to [4madjustment‐mode,[24m which is typically “[1mb[22m”
              for adjustment to both margins (the default), or  “[1ml[22m”  for  left
              alignment  (ragged right margin).  Any valid argument to [4mgroff[24m’s
              “.ad”  request  may  be  used.   See  [4mgroff[24m(7)  for  less‐common
              choices.

       [1m-rcR=1 [22mEnable  continuous rendering.  Output is not paginated; instead,
              one (potentially very long) page is produced.  This is  the  de‐
              fault  for  terminal and HTML devices.  Use [1m-rcR=0 [22mto disable it
              on terminal devices; on HTML devices, it cannot be disabled.

       [1m-rC1   [22mNumber output pages consecutively, in  strictly  increasing  se‐
              quence, rather than resetting the page number to 1 (or the value
              of register [1mP[22m) with each new [4mman[24m document.

       [1m-rCS=1 [22mSet  section headings (the argument(s) to [1m.SH[22m) in full capitals.
              This transformation is off by default because it  discards  case
              distinction information.

       [1m-rCT=1 [22mSet the man page topic (the first argument to [1m.TH[22m) in full capi‐
              tals  in headers and footers.  This transformation is off by de‐
              fault because it discards case distinction information.

       [1m-rD1   [22mEnable double‐sided layout, formatting footers for even and  odd
              pages  differently;  see  the  description  of [1m.TH [22min subsection
              “Document structure macros” above.

       [1m-rFT=[4m[22mfooter‐distance[0m
              Set distance of the footer relative to the bottom of the page to
              [4mfooter‐distance;[24m this amount is always negative.  At  one  half‐
              inch above this location, the page text is broken before writing
              the  footer.   Ignored  if continuous rendering is enabled.  The
              default is -0.5i.

       [1m-dHF=[4m[22mheading‐font[0m
              Set the font used for section and subsection headings;  the  de‐
              fault  is “[1mB[22m” (bold style of the default family).  Any valid ar‐
              gument to [4mgroff[24m’s “.ft” request may be used.  See [4mgroff[24m(7).

       [1m-rHY=0 [22mDisable automatic hyphenation.  Normally,  it  is  enabled  (1).
              The hyphenation mode is determined by the [4mgroff[24m locale; see sec‐
              tion “Localization“ of [4mgroff[24m(7).

       [1m-rIN=[4m[22mstandard‐indentation[0m
              Set  the  amount of indentation used for ordinary paragraphs ([1m.P[0m
              and its synonyms) and the default  indentation  amount  used  by
              [1m.IP[22m, [1m.RS[22m, [1m.TP[22m, and the deprecated [1m.HP[22m.  See subsection “Horizon‐
              tal  and  vertical spacing” above for the default.  For terminal
              devices, [4mstandard‐indentation[24m should always be an integer multi‐
              ple of unit “n” to get consistent indentation.

       [1m-rLL=[4m[22mline‐length[0m
              Set line length; the default is 78n  for  terminal  devices  and
              6.5i for typesetting devices.

       [1m-rLT=[4m[22mtitle‐length[0m
              Set  the line length for titles.  (“Titles” is the [4mroff[24m term for
              headers and footers.)  By default, it is set to the line  length
              (see [1m-rLL [22mabove).

       [1m-dMF=[4m[22mman‐page‐topic‐font[0m
              Set  the  font  used  for  man  page topics named in [1m.TH [22mand [1m.MR[0m
              calls; the default is “[1mI[22m” (italic style of the default  family).
              Any valid argument to [4mgroff[24m’s “.ft” request may be used.  If the
              [1mMF  [22mstring ends in “I”, it is assumed to be an oblique typeface,
              and italic corrections are applied before  and  after  man  page
              topics.

       [1m-rP[4m[22mn[24m   Start enumeration of pages at [4mn[24m.  The default is 1.

       [1m-rS[4m[22mtype‐size[0m
              Use  [4mtype‐size[24m  for  the document’s body text; acceptable values
              are 10, 11, or 12 points.  See subsection  “Font  style  macros”
              above for the default.

       [1m-rSN=[4m[22msubsection‐indentation[0m
              Set  indentation  of  subsection headings to [4msubsection‐indenta‐[0m
              [4mtion.[24m  See subsection “Horizontal and  vertical  spacing”  above
              for the default.

       [1m-rU1   [22mEnable  generation  of  URI hyperlinks in the [4mgrohtml[24m and [4mgrotty[0m
              output drivers.  [4mgrohtml[24m enables them by  default;  [4mgrotty[24m  does
              not,  pending more widespread pager support for OSC 8 escape se‐
              quences.  Use [1m-rU0 [22mto disable hyperlinks; this will make the ar‐
              guments to [1mMT [22mand [1mUR [22mcalls visible in the document text produced
              by link‐capable drivers.

       [1m-rX[4m[22mp[24m   Number successors of page [4mp[24m as [4mp[24ma, [4mp[24mb, [4mp[24mc, and  so  forth.   The
              register  tracking the suffixed page letter uses format “a” (see
              the “.af” request in [4mgroff[24m(7)).  For example,  the  option  [1m-rX2[0m
              produces  the  following  page  numbers: 1, 2, 2a, 2b, ..., 2aa,
              2ab, and so on.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/an.tmac[0m
              Most [4mman[24m macros are defined in this file.  It also loads  exten‐
              sions from [4man-ext.tmac[24m (see below).

       [4m/usr/share/groff/1.23.0/tmac/andoc.tmac[0m
              This  brief  [4mgroff[24m program detects whether the [4mman[24m or [4mmdoc[24m macro
              package is being used by a document and loads the correct  macro
              definitions,  taking advantage of the fact that pages using them
              must call [1m.TH [22mor [1m.Dd[22m, respectively, before any other macros.   A
              [4mman[24m program or user typing, for example, “[1mgroff -mandoc page.1[22m”,
              need  not know which package the file [4mpage.1[24m uses.  Multiple man
              pages, in either format, can  be  handled;  [4mandoc[24m  reloads  each
              macro package as necessary.

       [4m/usr/share/groff/1.23.0/tmac/an-ext.tmac[0m
              Except  for [1m.SB[22m, definitions of macros described above as exten‐
              sions are contained in this file; in some cases, they  are  sim‐
              pler  versions  of definitions appearing in [4man.tmac[24m, and are ig‐
              nored if the formatter is GNU [4mtroff[24m.  They  are  written  to  be
              compatible  with  AT&T [4mtroff[24m and permissively licensed—not copy‐
              lefted.  To reduce the risk of name space collisions, string and
              register names begin only with “[1mm[22m”[1m.  [22mWe encourage man  page  au‐
              thors who are concerned about portability to legacy Unix systems
              to  copy  these definitions into their pages, and maintainers of
              [4mtroff[24m implementations or  work‐alike  systems  that  format  man
              pages to re‐use them.

              The  definitions  for  these  macros are read after a page calls
              [1m.TH[22m, so they will replace any macros of the same names preceding
              it in your file.  If you use your own implementations  of  these
              macros, they must be defined after [1m.TH [22mis called to have any ef‐
              fect.   Furthermore, it is wise to define such page‐local macros
              (if at all) after the “Name” section to accommodate timid  [4mmake‐[0m
              [4mwhatis[24m  or [4mmandb[24m implementations that may give up their scan for
              indexing material early.

       [4m/usr/share/groff/1.23.0/tmac/man.tmac[0m
              This is a wrapper that loads [4man.tmac[24m.

       [4m/usr/share/groff/1.23.0/tmac/mandoc.tmac[0m
              This is a wrapper that loads [4mandoc.tmac[24m.

       [4m/usr/share/groff/site-tmac/man.local[0m
              Put site‐local changes and customizations into this file.

                     .\" Use narrower indentation on terminals and similar.
                     .if n .nr IN 4n
                     .\" Put only one space after the end of a sentence.
                     .ss 12 0 \" See groff(7).
                     .\" Keep pages narrow even on wide terminals.
                     .if n .if \n[LL]>78n .nr LL 78n
                     .\" Ensure hyperlinks are enabled for terminals.
                     .nr U 1

              On multi‐user systems, it is more  considerate  to  users  whose
              preferences  may  differ from the administrator’s to be less ag‐
              gressive with such settings, or to permit their override with  a
              user‐specific  [4mman.local[24m  file.  Place the requests below at the
              end of the site‐local file to manifest courtesy.
                     .soquiet \V[XDG_CONFIG_HOME]/man.local
                     .soquiet \V[HOME]/.man.local
              However, a security‐sandboxed [4mman[24m(1) program may lack permission
              to open such files.

[1mNotes[0m
       Some tips on troubleshooting your man pages follow.

       • Some ASCII characters look funny or copy and paste wrong.
              On devices with large glyph repertoires, like UTF‐8‐capable ter‐
              minals and PDF, several  keyboard  glyphs  are  mapped  to  code
              points  outside  the Unicode basic Latin range because that usu‐
              ally results in better typography in  the  general  case.   When
              documenting  GNU/Linux  command  or  C language syntax, however,
              this translation is sometimes not desirable.

              To get a “literal”...   ...should be input.
              ────────────────────────────────────────────
                                  [1m'   \(aq[0m
                                  [1m-   \-[0m
                                  [1m\   \(rs[0m
                                  [1m^   \(ha[0m
                                  [1m`   \(ga[0m
                                  [1m~   \(ti[0m
              ────────────────────────────────────────────

              Additionally, if a neutral double quote (") is needed in a macro
              argument, you can use [1m\(dq [22mto get it.  You should [4mnot[24m  use  [1m\(aq[0m
              for an ordinary apostrophe (as in “can’t”) or [1m\- [22mfor an ordinary
              hyphen  (as in “word‐aligned”).  Review subsection “Portability”
              above.

       • Do I ever need to use an empty macro argument ("")?
              Probably not.  When this seems necessary,  often  a  shorter  or
              clearer alternative is available.

                     Instead of...               ...should be considered.
              ────────────────────────────────────────────────────────────────
              [1m.TP ""                         .TP[0m
              ────────────────────────────────────────────────────────────────
              [1m.BI "" [4m[22mitalic‐text[24m [4mbold‐text[24m   [1m.IB [4m[22mitalic‐text[24m [4mbold‐text[0m
              ────────────────────────────────────────────────────────────────
              [1m.TH foo 1 "" "foo 1.2.3"       .TH foo 1 [4m[22myyyy[24m[1m‐[4m[22mmm[24m[1m‐[4m[22mdd[24m [1m"foo 1.2.3"[0m
              ────────────────────────────────────────────────────────────────
              [1m.IP "" 4n                      .IP[0m
              ────────────────────────────────────────────────────────────────
              [1m.IP "" 4n                      .RS 4n[0m
              [4mparagraph[24m                      [1m.P[0m
              ...                            [4mparagraph[0m
              ...                            [1m.RE[0m
              ────────────────────────────────────────────────────────────────
              [1m.B one two "" three            .B one two three[0m

              In the title heading ([1m.TH[22m), the date of the page’s last revision
              is  more  important than packaging information; it should not be
              omitted.  Ideally, a page maintainer will keep both up to date.

              [1m.IP [22mis sometimes ill‐understood and misused, especially when  no
              marker  argument  is supplied—an indentation argument is not re‐
              quired.  By setting an explicit indentation, you may be overrid‐
              ing the reader’s preference as set with  the  [1m-rIN  [22moption.   If
              your  page renders adequately without one, use the simpler form.
              If you need to indent multiple (unmarked)  paragraphs,  consider
              setting an inset region with [1m.RS [22mand [1m.RE [22minstead.

              In  the last example, the empty argument does have a subtly dif‐
              ferent effect than its suggested replacement: the empty argument
              causes an additional space character to be interpolated  between
              the  arguments  “two”  and  “three”—but it is a regular breaking
              space, so it can be discarded at the end of an output line.   It
              is  better  not to be subtle, particularly with space, which can
              be overlooked in source and rendered forms.

       • [1m.RS [22mdoesn’t indent relative to my indented paragraph.
              The [1m.RS [22mmacro sets the left margin; that  is,  the  position  at
              which  an  [4mordinary[24m paragraph ([1m.P [22mand its synonyms) will be set.
              [1m.IP[22m, [1m.TP[22m, and the deprecated [1m.HP [22muse the same  default  indenta‐
              tion.   If  not  given an argument, [1m.RS [22mmoves the left margin by
              this same amount.  To create an inset relative  to  an  indented
              paragraph,  call  [1m.RS [22mrepeatedly until an acceptable indentation
              is achieved, or give [1m.RS [22man  indentation  argument  that  is  at
              least  as much as the paragraph’s indentation amount relative to
              an adjacent [1m.P [22mparagraph.  See subsection “Horizontal and verti‐
              cal spacing” above for the values.

              Another approach you can use with tagged paragraphs is to  place
              an  [1m.RS [22mcall immediately after the paragraph tag; this will also
              force a break regardless of the width of the tag, which some au‐
              thors prefer.  Follow‐up paragraphs under the tag  can  then  be
              set  with [1m.P [22minstead of [1m.IP[22m.  Remember to use [1m.RE [22mto end the in‐
              dented region before starting the next tagged paragraph (at  the
              appropriate nesting level).

       • [1m.RE [22mdoesn’t move the inset back to the expected level.
       • warning: scaling unit invalid in context
       • warning: register 'an-saved-margin[4mn[24m' not defined
       • warning: register 'an-saved-prevailing-indent[4mn[24m' not defined
              The  [1m.RS  [22mmacro  takes an [4mindentation[24m [4mamount[24m as an argument; the
              [1m.RE [22mmacro’s argument is a specific [4minset[24m [4mlevel.[24m  [1m.RE 1  [22mgoes  to
              the  level  before any [1m.RS [22mmacros were called, [1m.RE 2 [22mgoes to the
              level of the first [1m.RS [22mcall you made, and so forth.  If you  de‐
              sire  symmetry in your macro calls, simply issue one [1m.RE [22mwithout
              an argument for each [1m.RS [22mthat precedes it.

              After calls to the [1m.SH [22mand [1m.SS [22msectioning macros,  all  relative
              insets  are cleared and calls to [1m.RE [22mhave no effect until [1m.RS [22mis
              used again.

       • Do I need to keep typing the indentation in a series of [1m.IP [22mcalls?
              Not if you don’t want to change it.  Review subsection “Horizon‐
              tal and vertical spacing” above.

                Instead of...     ...should be considered.
              ─────────────────────────────────────────────
              [1m.IP \(bu 4n         .IP \(bu 4n[0m
              [4mparagraph[24m           [4mparagraph[0m
              [1m.IP \(bu 4n         .IP \(bu[0m
              [4manother‐paragraph[24m   [4manother‐paragraph[0m
              ─────────────────────────────────────────────

       • Why doesn’t the package provide a string to insert an ellipsis?
              Examples of ellipsis usage are shown above, in subsection  “Com‐
              mand  synopsis  macros”.   The  idiomatic [4mroff[24m ellipsis is three
              dots (periods) with thin space escape  sequences  [1m\|  [22minternally
              separating  them.   Since  dots both begin control lines and are
              candidate end‐of‐sentence characters, however, it  is  sometimes
              necessary  to  prefix  and/or  suffix an ellipsis with the dummy
              character escape sequence [1m\&[22m.  That fact stands even if a string
              is defined to contain the sequence; further, if the string  ends
              with  [1m\&[22m, end‐of‐sentence detection is defeated when you use the
              string at the end of an actual  sentence.   (Ending  a  sentence
              with  an ellipsis is often poor style, but not always.)  A hypo‐
              thetical string [1mEL [22mthat  contained  an  ellipsis,  but  not  the
              trailing dummy character [1m\&[22m, would then need to be suffixed with
              the latter when not ending a sentence.

                  Instead of...              ...do this.
              ──────────────────────────────────────────────────
              [1m.ds EL \&.\|.\|.         Arguments are[0m
              [1mArguments are            .IR src‐file\~ .\|.\|.\&[0m
              [1m.IR src‐file\~ \*(EL\&   .IR dest‐dir .[0m
              [1m.IR dest‐dir .[0m
              ──────────────────────────────────────────────────

              The  first column practices a false economy; the savings in typ‐
              ing is offset by the cost of obscuring even the suggestion of an
              ellipsis to a casual reader of the source document, and  reduced
              portability  to  non‐[4mroff[24m man page formatters that cannot handle
              string definitions.

              There is an ellipsis code point in Unicode, and some fonts  have
              an  ellipsis glyph, which some man pages have accessed in a non‐
              portable way with the font‐dependent  [1m\N  [22mescape  sequence.   We
              discourage  the  use  of these; on terminals, they may crowd the
              dots into a half‐width character cell, and will  not  render  at
              all if the output device doesn’t have the glyph.  In syntax syn‐
              opses,  missing  ellipses  can  cause great confusion.  Dots and
              space are universally supported.

[1mAuthors[0m
       The initial GNU implementation of the [4mman[24m macro package was written  by
       James  Clark.   Later,  Werner Lemberg ⟨wl@gnu.org⟩ supplied the [1mS[22m, [1mLT[22m,
       and [1mcR [22mregisters, the last a 4.3BSD‐Reno [4mmdoc[24m(7) feature.  Larry Kollar
       ⟨kollar@alltel.net⟩ added the [1mFT[22m, [1mHY[22m, and [1mSN [22mregisters; the [1mHF  [22mstring;
       and  the  [1mPT  [22mand  [1mBT [22mmacros.  G. Branden Robinson ⟨g.branden.robinson@
       gmail.com⟩ implemented the [1mAD [22mand [1mMF [22mstrings; [1mCS[22m, [1mCT[22m, and [1mU  [22mregisters;
       and the [1mMR [22mmacro.  Except for [1m.SB[22m, the extension macros were written by
       Lemberg, Eric S. Raymond ⟨esr@thyrsus.com⟩, and Robinson.

       This document was originally written for the Debian GNU/Linux system by
       Susan  G.  Kleinmann ⟨sgk@debian.org⟩.  It was corrected and updated by
       Lemberg and Robinson.  The extension macros were documented by  Raymond
       and  Robinson.   Raymond  also  originated  the portability section, to
       which Ingo Schwarze ⟨schwarze@usta.de⟩ contributed most of the material
       on escape sequences.

[1mSee also[0m
       [4mtbl[24m(1), [4meqn[24m(1), and [4mrefer[24m(1) are preprocessors  used  with  man  pages.
       [4mman[24m(1)  describes the man page librarian on your system.  [4mgroff_mdoc[24m(7)
       details the [4mgroff[24m version of the BSD‐originated alternative macro pack‐
       age for man pages.

       [4mgroff_man[24m(7), [4mgroff[24m(7), [4mgroff_char[24m(7), [4mman[24m(7)

groff 1.23.0                      5 July 2023               [4mgroff_man_style[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_mdoc[24m(7)           Miscellaneous Information Manual         [4mgroff_mdoc[24m(7)

[1mName[0m
       groff_mdoc — compose BSD‐style manual (man) pages with GNU [4mroff[0m

[1mSynopsis[0m
       [1mgroff -mdoc [4m[22mfile[24m ...

[1mDescription[0m
       The GNU implementation of  the  [4mmdoc[24m  macro  package  is  part  of  the
       [4mgroff[24m(1)  document  formatting system.  [4mmdoc[24m is a structurally‐ and se‐
       mantically‐oriented  package  for  writing  Unix  manual   pages   with
       [4mtroff[24m(1).   Its  predecessor,  the  [4mman[24m(7) package, primarily addressed
       page layout and presentational concerns, leaving the selection of fonts
       and other typesetting details to the individual author.   This  discre‐
       tion has led to divergent styling practices among authors using it.

       [4mmdoc[24m organizes its macros into [4mdomains[24m.  The [4mpage[24m [4mstructure[24m [4mdomain[24m lays
       out  the  page  and  comprises  titles, section headings, displays, and
       lists.  The [4mgeneral[24m [4mtext[24m [4mdomain[24m supplies macros to quote or style text,
       or to interpolate common noun phrases.  The [4mmanual[24m [4mdomain[24m offers seman‐
       tic macros corresponding to the terminology used  by  practitioners  in
       discussion of Unix commands, routines, and files.  Manual domain macros
       distinguish  command‐line  arguments and options, function names, func‐
       tion parameters, pathnames, variables, cross references to other manual
       pages, and so on.  These terms are meaningful both to  the  author  and
       the readers of a manual page.  It is hoped that the resulting increased
       consistency  of  the  man page corpus will enable easier translation to
       future documentation tools.

       Throughout Unix documentation, a manual entry is referred to simply  as
       a  “man  page”, regardless of its length, without gendered implication,
       and irrespective of the macro package selected for its composition.

[1mGetting started[0m
       The [4mmdoc[24m package attempts to simplify man page authorship  and  mainte‐
       nance  without  requiring  mastery of the [4mroff[24m language.  This document
       presents only essential facts about [4mroff.[24m For further  background,  in‐
       cluding  a  discussion of basic typographical concepts like “breaking”,
       “filling”, and “adjustment”, see [4mroff[24m(7).  Specialized  units  of  mea‐
       surement  also arise, namely ens, vees, inches, and points, abbreviated
       “n”, “v”, “i”, and “p”, respectively;  see  section  “Measurements”  of
       [4mgroff[24m(7).

       For  brief  examples, we employ an arrow notation illustrating a trans‐
       formation of input on the left to rendered output on the  right.   Con‐
       sider the .[1mDq [22mmacro, which double‐quotes its arguments.
             [1m.Dq man page  [22m→ “man page”

   [1mUsage[0m
       An  [4mmdoc[24m  [4mmacro[24m  is  [4mcalled[24m  by placing the [4mroff[24m control character, ‘.’
       (dot) at the beginning of a line followed by its name.  In  this  docu‐
       ment,  we  often discuss a macro name with this leading dot to identify
       it clearly, but the dot is [4mnot[24m part of its name.  Space or tab  charac‐
       ters  can  separate the dot from the macro name.  Arguments may follow,
       separated from the macro name and each other by spaces, but  [4mnot[24m  tabs.
       The dot at the beginning of the line prepares the formatter to expect a
       macro  name.   A dot followed immediately by a newline is ignored; this
       is called the [4mempty[24m [4mrequest[24m.  To begin an input line with a dot  (or  a
       neutral  apostrophe  ‘'’) in some context other than a macro call, pre‐
       cede it with the ‘\&’ escape sequence; this is a dummy  character,  not
       formatted  for  output.  The backslash is the [4mroff[24m escape character; it
       can appear anywhere and it always followed by at least one more charac‐
       ter.  If followed by a newline, the backslash escapes  the  input  line
       break; you can thus keep input lines to a reasonable length without af‐
       fecting their interpretation.

       Macros  in  GNU  [4mtroff[24m accept an unlimited number of arguments, in con‐
       trast to other [4mtroff[24ms that often can’t handle more than nine.  In  lim‐
       ited  cases,  arguments  may be continued or extended on the next input
       line without resort to the ‘\[4mnewline[24m’ escape sequence;  see  subsection
       “Extended  arguments”  below.   Neutral  double quotes [1m" [22mcan be used to
       group multiple words into an argument; see  subsection  “Passing  space
       characters in an argument” below.

       Most  of [4mmdoc[24m’s general text and manual domain macros [4mparse[24m their argu‐
       ment lists for [4mcallable[24m macro names.  This means that  an  argument  in
       the  list  matching a general text or manual domain macro name (and de‐
       fined to be callable) will be called with the remaining arguments  when
       it is encountered.  In such cases, the argument, although the name of a
       macro, is not preceded by a dot.  Macro calls can thus be nested.  This
       approach to macro argument processing is a unique characteristic of the
       [4mmdoc[24m package, not a general feature of [4mroff[24m syntax.

       For  example,  the  option  macro,  .[1mOp[22m, may call the flag and argument
       macros, .[1mFl [22mand .[1mAr[22m, to specify an optional flag with an argument.
             [1m.Op Fl s Ar bytes      [22m→ [[1m-s [4m[22mbytes[24m]
       To prevent a word from being interpreted as a macro  name,  precede  it
       with the dummy character.
             [1m.Op \&Fl s \&Ar bytes  [22m→ [Fl s Ar bytes]

       In  this  document, macros whose argument lists are parsed for callable
       arguments are referred to as [4mparsed[24m, and those that may be called  from
       an  argument list are referred to as [4mcallable[24m.  This usage is a techni‐
       cal [4mfaux[24m [4mpas[24m, since all [4mmdoc[24m macros are  in  fact  interpreted  (unless
       prevented  with  ‘\&’),  but as it is cumbersome to constantly refer to
       macros as “being able  to  call  other  macros”,  we  employ  the  term
       “parsed”  instead.  Except where explicitly stated, all [4mmdoc[24m macros are
       parsed and callable.

       In the following, we term an [4mmdoc[24m macro that  starts  a  line  (with  a
       leading  dot)  a [4mcommand[24m if a distinction from those appearing as argu‐
       ments of other macros is necessary.

   [1mPassing space characters in an argument[0m
       Sometimes it is desirable to give a macro an argument containing one or
       more space characters, for instance to specify a particular arrangement
       of arguments demanded by the macro.  Additionally,  quoting  multi‐word
       arguments  that  are  to  be  treated  the same makes [4mmdoc[24m work faster;
       macros that parse arguments do so once (at most) for each.   For  exam‐
       ple, the function command .[1mFn [22mexpects its first argument to be the name
       of  a  function  and any remaining arguments to be function parameters.
       Because C language standards mandate the inclusion of types [4mand[24m identi‐
       fiers in the parameter lists of function definitions, each ‘Fn’ parame‐
       ter after the first will be at least two words in length,  as  in  “[4mint[0m
       [4mfoo[24m”.

       There  are  a few ways to embed a space in a macro argument.  One is to
       use the unadjustable  space  escape  sequence  [1m\[4m[22mspace[24m.   The  formatter
       treats  this  escape sequence as if it were any other printable charac‐
       ter, and will not break a line there as it would a word space when  the
       output  line  is  full.  This method is useful for macro arguments that
       are not expected to straddle an output line boundary, but has  a  draw‐
       back:  this  space does not adjust as others do when the output line is
       formatted.  An alternative is to use the unbreakable space  escape  se‐
       quence, ‘\~’, which cannot break but does adjust.  This [4mgroff[24m extension
       is widely but not perfectly portable.  Another method is to enclose the
       string in double quotes.
             [1m.Fn fetch char\ *str   [22m→ [1mfetch[22m([4mchar[24m [4m*str[24m)
             [1m.Fn fetch char\~*str   [22m→ [1mfetch[22m([4mchar[24m [4m*str[24m)
             [1m.Fn fetch "char *str"  [22m→ [1mfetch[22m([4mchar[24m [4m*str[24m)
       If  the  ‘\’ before the space in the first example or the double quotes
       in the third example were omitted, ‘.Fn’ would see three arguments, and
       the result would contain an undesired comma.
             [1m.Fn fetch char *str    [22m→ [1mfetch[22m([4mchar[24m, [4m*str[24m)

   [1mTrailing space characters[0m
       It is wise to remove trailing spaces from  the  ends  of  input  lines.
       Should  the need arise to put a formattable space at the end of a line,
       do so with the unadjustable or unbreakable space escape sequences.

   [1mFormatting the backslash glyph[0m
       When you need the [4mroff[24m escape character ‘\’ to appear  in  the  output,
       use  ‘\e’ or ‘\(rs’ instead.  Technically, ‘\e’ formats the current es‐
       cape character; it works reliably as long as no [4mroff[24m request is used to
       change it, which should never happen in man pages.  ‘\(rs’ is  a  [4mgroff[0m
       special  character escape sequence that explicitly formats the “reverse
       solidus” (backslash) glyph.

   [1mOther possible pitfalls[0m
       [4mgroff[24m [4mmdoc[24m warns when an  empty  input  line  is  found  outside  of  a
       [4mdisplay[24m, a topic presented in subsection “Examples and displays” below.
       Use empty requests to space the source document for maintenance.

       Leading  spaces  cause a break and are formatted.  Avoid this behaviour
       if possible.  Similarly, do not put more than one space  between  words
       in  an  ordinary text line; they are not “normalized” to a single space
       as other text formatters might do.

       Don’t try to use the neutral double quote character  ‘"’  to  represent
       itself  in  an  argument.   Use  the  special character escape sequence
       ‘\(dq’ to format it.  Further, this glyph should not be used  for  con‐
       ventional quotation; [4mmdoc[24m offers several quotation macros.  See subsec‐
       tion “Enclosure and quoting macros” below.

       The  formatter  attempts to detect the ends of sentences and by default
       puts the equivalent of two spaces between sentences on the same  output
       line;  see [4mroff[24m(7).  To defeat this detection in a parsed list of macro
       arguments, put ‘\&’ before the punctuation mark.  Thus,
             The
             .Ql .
             character.
             .Pp
             The
             .Ql \&.
             character.
             .Pp
             .No test .
             test
             .Pp
             .No test.
             test
       gives
             The ‘’.  character

             The ‘.’ character.

             test.  test

             test. test
       as output.  As can be seen in the first and third  output  lines,  [4mmdoc[0m
       handles punctuation characters specially in macro arguments.  This will
       be explained in section “General syntax” below.

       A  comment in the source file of a man page can begin with ‘[1m.\"[22m’ at the
       start of an input line, ‘[1m\"[22m’ after other input, or ‘[1m\#[22m’  anywhere  (the
       last is a [4mgroff[24m extension); the remainder of any such line is ignored.

[1mA man page template[0m
       Use [4mmdoc[24m to construct a man page from the following template.

             .\" The following three macro calls are required.
             .Dd date
             .Dt topic [section‐identifier [section‐keyword‐or‐title]]
             .Os [package‐or‐operating system [version‐or‐release]]
             .Sh Name
             .Nm topic
             .Nd summary‐description
             .\" The next heading is used in sections 2 and 3.
             .\" .Sh Library
             .\" The next heading is used in sections 1‐4, 6, 8, and 9.
             .Sh Synopsis
             .Sh Description
             .\" Uncomment and populate the following sections as needed.
             .\" .Sh "Implementation notes"
             .\" The next heading is used in sections 2, 3, and 9.
             .\" .Sh "Return values"
             .\" The next heading is used in sections 1, 3, 6, and 8.
             .\" .Sh Environment
             .\" .Sh Files
             .\" The next heading is used in sections 1, 6, and 8.
             .\" .Sh "Exit status"
             .\" .Sh Examples
             .\" The next heading is used in sections 1, 4, 6, 8, and 9.
             .\" .Sh Diagnostics
             .\" .Sh Compatibility
             .\" The next heading is used in sections 2, 3, 4, and 9.
             .\" .Sh Errors
             .\" .Sh "See also"
             .\" .Sh Standards
             .\" .Sh History
             .\" .Sh Authors
             .\" .Sh Caveats
             .\" .Sh Bugs

       The  first  items  in  the template are the commands .[1mDd[22m, .[1mDt[22m, and .[1mOs[22m.
       They identify the page  and  are  discussed  below  in  section  “Title
       macros”.

       The  remaining  items  in  the  template are section headings (.[1mSh[22m); of
       which “Name” and “Description” are mandatory.  These headings are  dis‐
       cussed  in  section  “Page  structure  domain”,  which  follows section
       “Manual domain”.  Familiarize yourself with manual domain macros first;
       we use them to illustrate the use of page structure domain macros.

[1mConventions[0m
       In the descriptions of macros below, square brackets surround  optional
       arguments.   An ellipsis (‘...’) represents repetition of the preceding
       argument zero or more times.  Alternative values  of  a  parameter  are
       separated  with  ‘|’.  If a mandatory parameter can take one of several
       alternative values, use braces to enclose the set, with spaces and  ‘|’
       separating the items.
             [1mztar [22m{[1mc [22m| [1mx[22m} [[1m-w [22m[[1m-y [22m| [1m-z[22m]] [[1m-f [4m[22marchive[24m] [4mmember[24m ...
       An  alternative to using braces is to separately synopsize distinct op‐
       eration modes, particularly if the list of valid optional arguments  is
       dependent on the user’s choice of a mandatory parameter.
             [1mztar c [22m[[1m-w [22m[[1m-y [22m| [1m-z[22m]] [[1m-f [4m[22marchive[24m] [4mmember[24m ...
             [1mztar x [22m[[1m-w [22m[[1m-y [22m| [1m-z[22m]] [[1m-f [4m[22marchive[24m] [4mmember[24m ...

       Most  macros  affect subsequent arguments until another macro or a new‐
       line is encountered.  For example, ‘[1m.Li ls Bq Ar file[22m’ doesn’t  produce
       ‘[1mls [file][22m’, but ‘[1mls [22m[[4mfile[24m]’.  Consequently, a warning message is emit‐
       ted for many commands if the first argument is itself a macro, since it
       cancels  the effect of the preceding one.  On rare occasions, you might
       want to format a word along with surrounding brackets as a literal.
             [1m.Li "ls [file]"  [22m→ [1mls [file] [4m[22m#[24m [4mlist[24m [4many[24m [4mfiles[24m [4mnamed[24m [4me,[24m [4mf,[24m [4mi,[24m [4mor[24m [4ml[0m

       Many macros possess an implicit width, used when they are contained  in
       lists  and  displays.   If  you avoid relying on these default measure‐
       ments, you escape potential conflicts with site‐local modifications  of
       the [4mmdoc[24m package.  Explicit [1m-width [22mand [1m-offset [22marguments to the .[1mBl [22mand
       .[1mBd [22mmacros are preferable.

[1mTitle macros[0m
       We  present  the  [1mmandatory  [22mtitle macros first due to their importance
       even though they formally belong to the page structure  domain  macros.
       They designate the topic, date of last revision, and the operating sys‐
       tem  or  software  project associated with the page.  Call each once at
       the beginning of the document.  They  populate  the  page  headers  and
       footers, which are in [4mroff[24m parlance termed “titles”.

       [1m.Dd [4m[22mdate[0m
               This  first macro of any [4mmdoc[24m manual records the last modifica‐
               tion date of the document source.  Arguments  are  concatenated
               and separated with space characters.

               Historically,  [4mdate[24m  was  written  in  U.S. traditional format,
               “[4mMonth[24m [4mday[24m , [4myear[24m” where [4mMonth[24m is the full month name  in  Eng‐
               lish, [4mday[24m an integer without a leading zero, and [4myear[24m the four‐
               digit  year.   This localism is not enforced, however.  You may
               prefer  ISO  8601  format,  [4mYYYY‐MM‐DD.[24m  A  [4mdate[24m  of  the  form
               ‘[1m$Mdocdate:  [4m[22mMonth[24m  [4mday[24m [4myear[24m [1m$[22m’ is also recognized.  It is used
               in OpenBSD manuals to automatically  insert  the  current  date
               when committing.

               This macro is neither callable nor parsed.

       [1m.Dt [4m[22mtopic[24m [[4msection‐identifier[24m [[4msection‐keyword‐or‐title[24m]]
               [4mtopic[24m  is  the  subject  of the man page.  A [4msection‐identifier[0m
               that begins with an integer in the range 1–9 or is one  of  the
               words ‘unass’, ‘draft’, or ‘paper’ selects a predefined section
               title.   This  use of “section” has nothing to do with the sec‐
               tion headings otherwise discussed in this page; it arises  from
               the organizational scheme of printed and bound Unix manuals.

               In  this  implementation,  the following titles are defined for
               integral section numbers.

                     1   General Commands Manual
                     2   System Calls Manual
                     3   Library Functions Manual
                     4   Kernel Interfaces Manual
                     5   File Formats Manual
                     6   Games Manual
                     7   Miscellaneous Information Manual
                     8   System Manager’s Manual
                     9   Kernel Developer’s Manual

               A section title may be arbitrary or one of the following abbre‐
               viations.

                     USD     User’s Supplementary Documents
                     PS1     Programmer’s Supplementary Documents
                     AMD     Ancestral Manual Documents
                     SMM     System Manager’s Manual
                     URM     User’s Reference Manual
                     PRM     Programmer’s Manual
                     KM      Kernel Manual
                     IND     Manual Master Index
                     LOCAL   Local Manual
                     CON     Contributed Software Manual

               For compatibility, ‘MMI’ can be used for ‘IND’, and  ‘LOC’  for
               ‘LOCAL’.   Values  from  the  previous table will specify a new
               section title.  If [4msection‐keyword‐or‐title[24m designates  a  com‐
               puter  architecture  recognized  by  [4mgroff[24m  [4mmdoc[24m,  its value is
               prepended to the default section title as specified by the sec‐
               ond parameter.  By default, the following architecture keywords
               are defined.

                   acorn26, acorn32, algor, alpha, amd64, amiga, amigappc,
                   arc, arm, arm26, arm32, armish, atari, aviion, beagle,
                   bebox, cats, cesfic, cobalt, dreamcast, emips, evbarm,
                   evbmips, evbppc, evbsh3, ews4800mips, hp300, hp700, hpcarm,
                   hpcmips, hpcsh, hppa, hppa64, i386, ia64, ibmnws, iyonix,
                   landisk, loongson, luna68k, luna88k, m68k, mac68k, macppc,
                   mips, mips64, mipsco, mmeye, mvme68k, mvme88k, mvmeppc,
                   netwinder, news68k, newsmips, next68k, ofppc, palm, pc532,
                   playstation2, pmax, pmppc, powerpc, prep, rs6000,
                   sandpoint, sbmips, sgi, sgimips, sh3, shark, socppc,
                   solbourne, sparc, sparc64, sun2, sun3, tahoe, vax, x68k,
                   x86_64, xen, zaurus

               If a section title is not determined after  the  above  matches
               have been attempted, [4msection‐keyword‐or‐title[24m is used.

               The  effects of varying ‘.Dt’ arguments on the page header con‐
               tent are shown below.  Observe how ‘\&’ prevents the numeral  2
               from being used to look up a predefined section title.

                 .Dt foo 2       →  foo(2)     System Calls Manual      foo(2)
                 .Dt foo 2 m68k  →  foo(2)   m68k System Calls Manual   foo(2)
                 .Dt foo 2 baz   →  foo(2)     System Calls Manual      foo(2)
                 .Dt foo \&2 baz →  foo(2)             baz              foo(2)
                 .Dt foo "" baz  →  foo                baz                 foo
                 .Dt foo M Z80   →  foo(M)             Z80              foo(M)

               [4mroff[24m  strings  define  section  titles and architecture identi‐
               fiers.  Site‐specific additions might  be  found  in  the  file
               [4mmdoc.local[24m; see section “Files” below.

               This macro is neither callable nor parsed.

       [1m.Os [22m[[4moperating‐system‐or‐package‐name[24m [[4mversion‐or‐release[24m]]
               This  macro  associates  the document with a software distribu‐
               tion.  When composing a man page to be included in the base in‐
               stallation of an operating system, do not provide an  argument;
               [4mmdoc[24m  will  supply it.  In this implementation, that default is
               “GNU”.  It may be overridden in the  site  configuration  file,
               [4mmdoc.local[24m;  see  section  “Files”  below.  A portable software
               package maintaining its own man pages can supply its  name  and
               version  number or release identifier as optional arguments.  A
               [4mversion‐or‐release[24m argument should use the  standard  nomencla‐
               ture  for the software specified.  In the following table, rec‐
               ognized [4mversion‐or‐release[24m arguments for some predefined  oper‐
               ating systems are listed.  As with .[1mDt[22m, site additions might be
               defined in [4mmdoc.local[24m.

                     ATT        7th, 7, III, 3, V, V.2, V.3, V.4

                     BSD        3, 4, 4.1, 4.2, 4.3, 4.3t, 4.3T, 4.3r, 4.3R,
                                4.4

                     NetBSD     0.8, 0.8a, 0.9, 0.9a, 1.0, 1.0a, 1.1, 1.2,
                                1.2a, 1.2b, 1.2c, 1.2d, 1.2e, 1.3, 1.3a, 1.4,
                                1.4.1, 1.4.2, 1.4.3, 1.5, 1.5.1, 1.5.2, 1.5.3,
                                1.6, 1.6.1, 1.6.2, 1.6.3, 2.0, 2.0.1, 2.0.2,
                                2.0.3, 2.1, 3.0, 3.0.1, 3.0.2, 3.0.3, 3.1,
                                3.1.1, 4.0, 4.0.1, 5.0, 5.0.1, 5.0.2, 5.1,
                                5.1.2, 5.1.3, 5.1.4, 5.2, 5.2.1, 5.2.2, 6.0,
                                6.0.1, 6.0.2, 6.0.3, 6.0.4, 6.0.5, 6.0.6, 6.1,
                                6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 7.0, 7.0.1,
                                7.0.2, 7.1, 7.1.1, 7.1.2, 7.2, 8.0, 8.1

                     FreeBSD    1.0, 1.1, 1.1.5, 1.1.5.1, 2.0, 2.0.5, 2.1,
                                2.1.5, 2.1.6, 2.1.7, 2.2, 2.2.1, 2.2.2, 2.2.5,
                                2.2.6, 2.2.7, 2.2.8, 2.2.9, 3.0, 3.1, 3.2,
                                3.3, 3.4, 3.5, 4.0, 4.1, 4.1.1, 4.2, 4.3, 4.4,
                                4.5, 4.6, 4.6.2, 4.7, 4.8, 4.9, 4.10, 4.11,
                                5.0, 5.1, 5.2, 5.2.1, 5.3, 5.4, 5.5, 6.0, 6.1,
                                6.2, 6.3, 6.4, 7.0, 7.1, 7.2, 7.3, 7.4, 8.0,
                                8.1, 8.2, 8.3, 8.4, 9.0, 9.1, 9.2, 9.3, 10.0,
                                10.1, 10.2, 10.3, 10.4, 11.0, 11.1, 11.2,
                                11.3, 12.0, 12.1

                     OpenBSD    2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8,
                                2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7,
                                3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6,
                                4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5,
                                5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4,
                                6.5, 6.6

                     DragonFly  1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8,
                                1.8.1, 1.9, 1.10, 1.11, 1.12, 1.12.2, 1.13,
                                2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8,
                                2.9, 2.9.1, 2.10, 2.10.1, 2.11, 2.12, 2.13,
                                3.0, 3.0.1, 3.0.2, 3.1, 3.2, 3.2.1, 3.2.2,
                                3.3, 3.4, 3.4.1, 3.4.2, 3.4.3, 3.5, 3.6,
                                3.6.1, 3.6.2, 3.7, 3.8, 3.8.1, 3.8.2, 4.0,
                                4.0.1, 4.0.2, 4.0.3, 4.0.4, 4.0.5, 4.0.6, 4.1,
                                4.2, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.3, 4.4,
                                4.4.1, 4.4.2, 4.4.3, 4.5, 4.6, 4.6.1, 4.6.2,
                                4.7, 4.8, 4.8.1, 4.9, 5.0, 5.0.1, 5.0.2, 5.1,
                                5.2, 5.2.1, 5.2.2, 5.3, 5.4, 5.4.1, 5.4.2,
                                5.4.3, 5.5, 5.6, 5.6.1, 5.6.2

                     Darwin     8.0.0, 8.1.0, 8.2.0, 8.3.0, 8.4.0, 8.5.0,
                                8.6.0, 8.7.0, 8.8.0, 8.9.0, 8.10.0, 8.11.0,
                                9.0.0, 9.1.0, 9.2.0, 9.3.0, 9.4.0, 9.5.0,
                                9.6.0, 9.7.0, 9.8.0, 10.0.0, 10.1.0, 10.2.0,
                                10.3.0, 10.4.0, 10.5.0, 10.6.0, 10.7.0,
                                10.8.0, 11.0.0, 11.1.0, 11.2.0, 11.3.0,
                                11.4.0, 11.5.0, 12.0.0, 12.1.0, 12.2.0,
                                13.0.0, 13.1.0, 13.2.0, 13.3.0, 13.4.0,
                                14.0.0, 14.1.0, 14.2.0, 14.3.0, 14.4.0,
                                14.5.0, 15.0.0, 15.1.0, 15.2.0, 15.3.0,
                                15.4.0, 15.5.0, 15.6.0, 16.0.0, 16.1.0,
                                16.2.0, 16.3.0, 16.4.0, 16.5.0, 16.6.0,
                                17.0.0, 17.1.0, 17.2.0, 17.3.0, 17.4.0,
                                17.5.0, 17.6.0, 17.7.0, 18.0.0, 18.1.0,
                                18.2.0, 18.3.0, 18.4.0, 18.5.0, 18.6.0,
                                18.7.0, 19.0.0, 19.1.0, 19.2.0

               Historically,  the first argument used with .[1mDt [22mwas [1mBSD [22mor [1mATT[22m.
               An unrecognized version argument after  [1mATT  [22mis  replaced  with
               “Unix”; for other predefined abbreviations, it is ignored and a
               warning  diagnostic emitted.  Otherwise, unrecognized arguments
               are displayed verbatim in the page footer.  For instance,  this
               page  uses  “[1m.Os  groff 1.23.0[22m” whereas a locally produced page
               might employ “[1m.Os "UXYZ CS Department"[22m”, omitting versioning.

               This macro is neither callable nor parsed.

[1mIntroduction to manual and general text domains[0m
   [1mWhat’s in a Name[22m...
       The manual domain macro names are derived from the day to day  informal
       language  used  to  describe  commands,  subroutines and related files.
       Slightly different variations of this language are used to describe the
       three different aspects of writing a man page.  First, there is the de‐
       scription of [4mmdoc[24m macro command usage.  Second is the description of  a
       Unix  command [4mwith[24m [4mmdoc[24m macros, and third, the description of a command
       to a user in the verbal sense; that is, discussion of a command in  the
       text of a man page.

       In  the  first case, [4mtroff[24m macros are themselves a type of command; the
       general syntax for a [4mtroff[24m command is:

             [1m.Xx argument1 argument2 ...[0m

       ‘.Xx’ is a macro command, and anything following it are arguments to be
       processed.  In the second case, the description of a Unix command using
       the manual domain macros is a bit more involved; a  typical  “Synopsis”
       command line might be displayed as:

             [1mfilter [22m[[1m-flag[22m] ⟨[4minfile[24m⟩ ⟨[4moutfile[24m⟩

       Here,  [1mfilter  [22mis  the command name and the bracketed string [1m-flag [22mis a
       [4mflag[24m argument designated as optional by the option brackets.   In  [4mmdoc[0m
       terms,  ⟨[4minfile[24m⟩ and ⟨[4moutfile[24m⟩ are called [4mmeta[24m [4marguments[24m; in this exam‐
       ple, the user has to replace the meta expressions given in angle brack‐
       ets with real file names.  Note that in this  document  meta  arguments
       are  used  to describe [4mmdoc[24m commands; in most man pages, meta variables
       are not specifically written with angle brackets.  The macros that for‐
       matted the above example:

             .Nm filter
             .Op Fl flag
             .Ao Ar infile Ac Ao Ar outfile Ac

       In the third case, discussion of commands and command  syntax  includes
       both  examples  above, but may add more detail.  The arguments ⟨[4minfile[24m⟩
       and ⟨[4moutfile[24m⟩ from the example above might be referred to  as  [4moperands[0m
       or [4mfile[24m [4marguments[24m.  Some command‐line argument lists are quite long:

             [1mmake  [22m[[1m-eiknqrstv[22m] [[1m-D [4m[22mvariable[24m] [[1m-d [4m[22mflags[24m] [[1m-f [4m[22mmakefile[24m] [[1m-I[0m
                   [4mdirectory[24m] [[1m-j [4m[22mmax_jobs[24m] [[4mvariable[24m=[4mvalue[24m] [[4mtarget[24m ...]

       Here  one  might  talk about the command [4mmake[24m and qualify the argument,
       [4mmakefile[24m, as an argument to the flag, [1m-f[22m, or discuss the optional  file
       operand  [4mtarget[24m.  In the verbal context, such detail can prevent confu‐
       sion, however the [4mmdoc[24m package does not have a macro for an argument [4mto[0m
       a flag.  Instead the ‘Ar’ argument macro is used for an operand or file
       argument like [4mtarget[24m as well as an argument to a  flag  like  [4mvariable[24m.
       The make command line was produced from:

             .Nm make
             .Op Fl eiknqrstv
             .Op Fl D Ar variable
             .Op Fl d Ar flags
             .Op Fl f Ar makefile
             .Op Fl I Ar directory
             .Op Fl j Ar max_jobs
             .Op Ar variable Ns = Ns Ar value
             .Bk
             .Op Ar target ...
             .Ek

       The ‘.Bk’ and ‘.Ek’ macros are explained in “Keeps”.

   [1mGeneral Syntax[0m
       The manual domain and general text domain macros share a similar syntax
       with  a  few  minor  deviations; most notably, ‘.Ar’, ‘.Fl’, ‘.Nm’, and
       ‘.Pa’ differ only when called without arguments; and  ‘.Fn’  and  ‘.Xr’
       impose  an order on their argument lists.  All manual domain macros are
       capable of recognizing and properly handling punctuation, provided each
       punctuation character is separated by a leading space.  If a command is
       given:

             [1m.Ar sptr, ptr),[0m

       The result is:

             [4msptr,[24m [4mptr),[0m

       The punctuation is not recognized and all is output in the font used by
       ‘.Ar’.  If the punctuation is separated by a leading white space:

             [1m.Ar sptr , ptr ) ,[0m

       The result is:

             [4msptr[24m, [4mptr[24m),

       The punctuation is now recognized and output in the default  font  dis‐
       tinguishing  it from the argument strings.  To remove the special mean‐
       ing from a punctuation character, escape it with ‘\&’.

       The following punctuation characters are recognized by [4mmdoc[24m:

                 [1m.         ,         :         ;         ([0m
                 [1m)         [         ]         ?         ![0m

       [4mtroff[24m is limited as a macro language, and has difficulty when presented
       with a string containing certain mathematical,  logical,  or  quotation
       character sequences:

                   {+,-,/,*,%,<,>,<=,>=,=,==,&,`,',"}

       The problem is that [4mtroff[24m may assume it is supposed to actually perform
       the  operation  or  evaluation suggested by the characters.  To prevent
       the accidental evaluation of these characters, escape them  with  ‘\&’.
       Typical  syntax is shown in the first manual domain macro displayed be‐
       low, ‘.Ad’.

[1mManual domain[0m
   [1mAddresses[0m
       The address macro identifies an address construct.

             [1mUsage: .Ad [22m⟨address⟩ ...

                      [1m.Ad addr1           [4m[22maddr1[0m
                      [1m.Ad addr1 .         [4m[22maddr1[24m.
                      [1m.Ad addr1 , file2   [4m[22maddr1[24m, [4mfile2[0m
                      [1m.Ad f1 , f2 , f3 :  [4m[22mf1[24m, [4mf2[24m, [4mf3[24m:
                      [1m.Ad addr ) ) ,      [4m[22maddr[24m)),

       The default width is 12n.

   [1mAuthor Name[0m
       The ‘.An’ macro is used to specify the name of the author of  the  item
       being documented, or the name of the author of the actual manual page.

             [1mUsage: .An [22m⟨author name⟩ ...

                      [1m.An "Joe Author"        [22mJoe Author

                      [1m.An "Joe Author" ,      [22mJoe Author,

                      [1m.An "Joe Author" Aq nobody@FreeBSD.org[0m
                                              Joe Author <nobody@FreeBSD.org>

                      [1m.An "Joe Author" ) ) ,  [22mJoe Author)),

       The default width is 12n.

       In  a  section titled “Authors”, ‘An’ causes a break, allowing each new
       name to appear on its own line.  If this is not desirable,

             .An -nosplit

       call will turn this off.  To turn splitting back on, write

             .An -split

   [1mArguments[0m
       The [1m.Ar [22margument macro may be used whenever an argument is  referenced.
       If called without arguments, ‘[4mfile[24m [4m...[24m’ is output.  This places the el‐
       lipsis  in italics, which is ugly and incorrect, and will be noticed on
       terminals that underline text instead of using an oblique typeface.  We
       recommend using ‘.Ar file No ...’ instead.

             [1mUsage: .Ar [22m[⟨argument⟩] ...

                      [1m.Ar              [4m[22mfile[24m [4m...[0m
                      [1m.Ar file No ...  [4m[22mfile[24m ...
                      [1m.Ar file1        [4m[22mfile1[0m
                      [1m.Ar file1 .      [4m[22mfile1[24m.
                      [1m.Ar file1 file2  [4m[22mfile1[24m [4mfile2[0m
                      [1m.Ar f1 f2 f3 :   [4m[22mf1[24m [4mf2[24m [4mf3[24m:
                      [1m.Ar file ) ) ,   [4m[22mfile[24m)),

       The default width is 12n.

   [1mConfiguration Declaration (Section Four Only)[0m
       The ‘.Cd’ macro is used to demonstrate a [4mconfig[24m(8)  declaration  for  a
       device interface in a section four manual.

             [1mUsage: .Cd [22m⟨argument⟩ ...

                      [1m.Cd "device le0 at scode?"  device le0 at scode?[0m

       In  a  section  titled “Synopsis”, ‘Cd’ causes a break before and after
       its arguments.

       The default width is 12n.

   [1mCommand Modifiers[0m
       The command modifier is identical to the ‘.Fl’ (flag) command with  the
       exception that the ‘.Cm’ macro does not assert a dash in front of every
       argument.   Traditionally  flags are marked by the preceding dash, how‐
       ever, some commands or subsets of commands do not  use  them.   Command
       modifiers  may  also  be specified in conjunction with interactive com‐
       mands such as editor commands.  See “Flags”.

       The default width is 10n.

   [1mDefined Variables[0m
       A variable (or constant) that is defined in an include file  is  speci‐
       fied by the macro ‘.Dv’.

             [1mUsage: .Dv [22m⟨defined‐variable⟩ ...

                      [1m.Dv MAXHOSTNAMELEN  [22mMAXHOSTNAMELEN
                      [1m.Dv TIOCGPGRP )     [22mTIOCGPGRP)

       The default width is 12n.

   [1mErrnos[0m
       The  ‘.Er’  errno macro specifies the error return value for section 2,
       3, and 9 library routines.  The second example below shows  ‘.Er’  used
       with the ‘.Bq’ general text domain macro, as it would be used in a sec‐
       tion two manual page.

             [1mUsage: .Er [22m⟨errno type⟩ ...

                      [1m.Er ENOENT      [22mENOENT
                      [1m.Er ENOENT ) ;  [22mENOENT);
                      [1m.Bq Er ENOTDIR  [22m[ENOTDIR]

       The default width is 17n.

   [1mEnvironment Variables[0m
       The ‘.Ev’ macro specifies an environment variable.

             [1mUsage: .Ev [22m⟨argument⟩ ...

                      [1m.Ev DISPLAY        [22mDISPLAY
                      [1m.Ev PATH .         [22mPATH.
                      [1m.Ev PRINTER ) ) ,  [22mPRINTER)),

       The default width is 15n.

   [1mFlags[0m
       The  ‘.Fl’  macro handles command‐line flags.  It prepends a dash, ‘-’,
       to the flag.  For interactive command flags that are not prepended with
       a dash, the ‘.Cm’ (command modifier) macro is  identical,  but  without
       the dash.

             [1mUsage: .Fl [22m⟨argument⟩ ...

                      [1m.Fl          -[0m
                      [1m.Fl cfv      -cfv[0m
                      [1m.Fl cfv .    -cfv[22m.
                      [1m.Cm cfv .    cfv[22m.
                      [1m.Fl s v t    -s -v -t[0m
                      [1m.Fl - ,      --[22m,
                      [1m.Fl xyz ) ,  -xyz[22m),
                      [1m.Fl |        - [22m|

       The  ‘.Fl’  macro  without any arguments results in a dash representing
       stdin/stdout.  Note that giving ‘.Fl’ a single dash will result in  two
       dashes.

       The default width is 12n.

   [1mFunction Declarations[0m
       The  ‘.Fd’  macro is used in the “Synopsis” section with section two or
       three functions.  It is neither callable nor parsed.

             [1mUsage: .Fd [22m⟨argument⟩ ...

                      [1m.Fd "#include <sys/types.h>"  #include <sys/types.h>[0m

       In a section titled “Synopsis”, ‘Fd’ causes a break if a  function  has
       already  been  presented and a break has not occurred, leaving vertical
       space between one function declaration and the next.

       In a section titled “Synopsis”, the ‘In’ macro represents the  [1m#include[0m
       statement,  and  is  the short form of the above example.  It specifies
       the C header file as being included in a C program.  It also  causes  a
       break.

       While  not in the “Synopsis” section, it represents the header file en‐
       closed in angle brackets.

             [1mUsage: .In [22m⟨header file⟩

                      [1m.In stdio.h  [22m<[4mstdio.h[24m>
                      [1m.In stdio.h  [22m<[4mstdio.h[24m>

   [1mFunction Types[0m
       This macro is intended for the “Synopsis” section.  It may be used any‐
       where else in the man page without problems, but its main purpose is to
       present  the  function  type  (in  BSD  kernel  normal  form)  for  the
       “Synopsis” of sections two and three.  (It causes a break, allowing the
       function name to appear on the next line.)

             [1mUsage: .Ft [22m⟨type⟩ ...

                      [1m.Ft struct stat  [4m[22mstruct[24m [4mstat[0m

   [1mFunctions (Library Routines)[0m
       The ‘.Fn’ macro is modeled on ANSI C conventions.

             [1mUsage: .Fn [22m⟨function⟩ [⟨parameter⟩] ...

                      [1m.Fn getchar              getchar[22m()
                      [1m.Fn strlen ) ,           strlen[22m()),
                      [1m.Fn align "char *ptr" ,  align[22m([4mchar[24m [4m*ptr[24m),

       Note  that  any call to another macro signals the end of the ‘.Fn’ call
       (it will insert a closing parenthesis at that point).

       For functions with many parameters (which is rare),  the  macros  ‘.Fo’
       (function  open)  and  ‘.Fc’  (function  close)  may be used with ‘.Fa’
       (function argument).

       Example:

             .Ft int
             .Fo res_mkquery
             .Fa "int op"
             .Fa "char *dname"
             .Fa "int class"
             .Fa "int type"
             .Fa "char *data"
             .Fa "int datalen"
             .Fa "struct rrec *newrr"
             .Fa "char *buf"
             .Fa "int buflen"
             .Fc

       Produces:

             [4mint[24m [1mres_mkquery[22m([4mint[24m [4mop[24m, [4mchar[24m [4m*dname[24m, [4mint[24m [4mclass[24m, [4mint[24m [4mtype[24m,
             [4mchar[24m [4m*data[24m, [4mint[24m [4mdatalen[24m, [4mstruct[24m [4mrrec[24m [4m*newrr[24m, [4mchar[24m [4m*buf[24m,
             [4mint[24m [4mbuflen[24m)

       Typically, in a “Synopsis” section, the function delcaration will begin
       the line.  If more than one function is  presented  in  the  “Synopsis”
       section  and  a  function  type has not been given, a break will occur,
       leaving vertical space between the current and prior function names.

       The default width values of ‘.Fn’ and ‘.Fo’ are 12n  and  16n,  respec‐
       tively.

   [1mFunction Arguments[0m
       The  ‘.Fa’  macro  is  used to refer to function arguments (parameters)
       outside  of  the  “Synopsis”  section  of  the  manual  or  inside  the
       “Synopsis”  section  if the enclosure macros ‘.Fo’ and ‘.Fc’ instead of
       ‘.Fn’ are used.  ‘.Fa’ may also be used to refer to structure members.

             [1mUsage: .Fa [22m⟨function argument⟩ ...

                      [1m.Fa d_namlen ) ) ,  [4m[22md_namlen[24m)),
                      [1m.Fa iov_len         [4m[22miov_len[0m

       The default width is 12n.

   [1mReturn Values[0m
       The ‘.Rv’ macro generates text for use in the “Return values” section.

             [1mUsage: .Rv [22m[-std] [⟨function⟩ ...]

       For example, ‘.Rv -std atexit’ produces:

             The [1matexit[22m() function returns the value 0 if successful; other‐
             wise the value -1 is returned and the global variable [4merrno[24m is
             set to indicate the error.

       The [1m-std [22moption is valid only for manual page sections 2 and  3.   Cur‐
       rently, this macro does nothing if used without the [1m-std [22mflag.

   [1mExit Status[0m
       The ‘.Ex’ macro generates text for use in the “Diagnostics” section.

             [1mUsage: .Ex [22m[-std] [⟨utility⟩ ...]

       For example, ‘.Ex -std cat’ produces:

             The [1mcat [22mutility exits 0 on success, and >0 if an error occurs.

       The  [1m-std  [22moption  is  valid  only for manual page sections 1, 6 and 8.
       Currently, this macro does nothing if used without the [1m-std [22mflag.

   [1mInteractive Commands[0m
       The ‘.Ic’ macro designates an interactive or internal command.

             [1mUsage: .Ic [22m⟨argument⟩ ...

                      [1m.Ic :wq                :wq[0m
                      [1m.Ic "do while {...}"   do while {...}[0m
                      [1m.Ic setenv , unsetenv  setenv[22m, [1munsetenv[0m

       The default width is 12n.

   [1mLibrary Names[0m
       The ‘.Lb’ macro is used to specify the library where a particular func‐
       tion is compiled in.

             [1mUsage: .Lb [22m⟨argument⟩ ...

       Available arguments to ‘.Lb’ and their results are:

             [1mlibarchive     [22mReading and  Writing  Streaming  Archives  Library
                            (libarchive, -larchive)
             [1mlibarm         [22mARM Architecture Library (libarm, -larm)
             [1mlibarm32       [22mARM32 Architecture Library (libarm32, -larm32)
             [1mlibbluetooth   [22mBluetooth Library (libbluetooth, -lbluetooth)
             [1mlibbsm         [22mBasic Security Module Library (libbsm, -lbsm)
             [1mlibc           [22mStandard C Library (libc, -lc)
             [1mlibc_r         [22mReentrant C Library (libc_r, -lc_r)
             [1mlibcalendar    [22mCalendar    Arithmetic    Library    (libcalendar,
                            -lcalendar)
             [1mlibcam         [22mCommon Access Method User Library (libcam, -lcam)
             [1mlibcdk         [22mCurses Development Kit Library (libcdk, -lcdk)
             [1mlibcipher      [22mFreeSec Crypt Library (libcipher, -lcipher)
             [1mlibcompat      [22mCompatibility Library (libcompat, -lcompat)
             [1mlibcrypt       [22mCrypt Library (libcrypt, -lcrypt)
             [1mlibcurses      [22mCurses Library (libcurses, -lcurses)
             [1mlibdevinfo     [22mDevice and Resource  Information  Utility  Library
                            (libdevinfo, -ldevinfo)
             [1mlibdevstat     [22mDevice Statistics Library (libdevstat, -ldevstat)
             [1mlibdisk        [22mInterface  to  Slice  and Partition Labels Library
                            (libdisk, -ldisk)
             [1mlibdwarf       [22mDWARF Access Library (libdwarf, -ldwarf)
             [1mlibedit        [22mCommand Line Editor Library (libedit, -ledit)
             [1mlibelf         [22mELF Access Library (libelf, -lelf)
             [1mlibevent       [22mEvent Notification Library (libevent, -levent)
             [1mlibfetch       [22mFile Transfer Library for URLs (libfetch, -lfetch)
             [1mlibform        [22mCurses Form Library (libform, -lform)
             [1mlibgeom        [22mUserland API Library  for  kernel  GEOM  subsystem
                            (libgeom, -lgeom)
             [1mlibgpib        [22mGeneral‐Purpose   Instrument  Bus  (GPIB)  library
                            (libgpib, -lgpib)
             [1mlibi386        [22mi386 Architecture Library (libi386, -li386)
             [1mlibintl        [22mInternationalized   Message    Handling    Library
                            (libintl, -lintl)
             [1mlibipsec       [22mIPsec Policy Control Library (libipsec, -lipsec)
             [1mlibipx         [22mIPX  Address  Conversion  Support Library (libipx,
                            -lipx)
             [1mlibiscsi       [22miSCSI protocol library (libiscsi, -liscsi)
             [1mlibjail        [22mJail Library (libjail, -ljail)
             [1mlibkiconv      [22mKernel side iconv library (libkiconv, -lkiconv)
             [1mlibkse         [22mN:M Threading Library (libkse, -lkse)
             [1mlibkvm         [22mKernel Data Access Library (libkvm, -lkvm)
             [1mlibm           [22mMath Library (libm, -lm)
             [1mlibm68k        [22mm68k Architecture Library (libm68k, -lm68k)
             [1mlibmagic       [22mMagic  Number   Recognition   Library   (libmagic,
                            -lmagic)
             [1mlibmd          [22mMessage  Digest  (MD4,  MD5, etc.) Support Library
                            (libmd, -lmd)
             [1mlibmemstat     [22mKernel   Memory   Allocator   Statistics   Library
                            (libmemstat, -lmemstat)
             [1mlibmenu        [22mCurses Menu Library (libmenu, -lmenu)
             [1mlibnetgraph    [22mNetgraph User Library (libnetgraph, -lnetgraph)
             [1mlibnetpgp      [22mNetpgp   signing,   verification,  encryption  and
                            decryption (libnetpgp, -lnetpgp)
             [1mlibossaudio    [22mOSS   Audio   Emulation   Library    (libossaudio,
                            -lossaudio)
             [1mlibpam         [22mPluggable  Authentication  Module Library (libpam,
                            -lpam)
             [1mlibpcap        [22mPacket Capture Library (libpcap, -lpcap)
             [1mlibpci         [22mPCI Bus Access Library (libpci, -lpci)
             [1mlibpmc         [22mPerformance Counters Library (libpmc, -lpmc)
             [1mlibposix       [22mPOSIX Compatibility Library (libposix, -lposix)
             [1mlibprop        [22mProperty  Container   Object   Library   (libprop,
                            -lprop)
             [1mlibpthread     [22mPOSIX Threads Library (libpthread, -lpthread)
             [1mlibpuffs       [22mpuffs Convenience Library (libpuffs, -lpuffs)
             [1mlibrefuse      [22mFile   System  in  Userspace  Convenience  Library
                            (librefuse, -lrefuse)
             [1mlibresolv      [22mDNS Resolver Library (libresolv, -lresolv)
             [1mlibrpcsec_gss  [22mRPC GSS‐API Authentication Library (librpcsec_gss,
                            -lrpcsec_gss)
             [1mlibrpcsvc      [22mRPC Service Library (librpcsvc, -lrpcsvc)
             [1mlibrt          [22mPOSIX Real‐time Library (librt, -lrt)
             [1mlibsdp         [22mBluetooth Service Discovery Protocol User  Library
                            (libsdp, -lsdp)
             [1mlibssp         [22mBuffer Overflow Protection Library (libssp, -lssp)
             [1mlibSystem      [22mSystem Library (libSystem, -lSystem)
             [1mlibtermcap     [22mTermcap Access Library (libtermcap, -ltermcap)
             [1mlibterminfo    [22mTerminal    Information    Library   (libterminfo,
                            -lterminfo)
             [1mlibthr         [22m1:1 Threading Library (libthr, -lthr)
             [1mlibufs         [22mUFS File System Access Library (libufs, -lufs)
             [1mlibugidfw      [22mFile System Firewall Interface Library (libugidfw,
                            -lugidfw)
             [1mlibulog        [22mUser Login Record Library (libulog, -lulog)
             [1mlibusbhid      [22mUSB Human Interface  Devices  Library  (libusbhid,
                            -lusbhid)
             [1mlibutil        [22mSystem Utilities Library (libutil, -lutil)
             [1mlibvgl         [22mVideo Graphics Library (libvgl, -lvgl)
             [1mlibx86_64      [22mx86_64 Architecture Library (libx86_64, -lx86_64)
             [1mlibz           [22mCompression Library (libz, -lz)

       Site‐specific additions might be found in the file [4mmdoc.local[24m; see sec‐
       tion “Files” below.

       In a section titled “Library”, ‘Lb’ causes a break before and after its
       arguments.

   [1mLiterals[0m
       The  ‘Li’  literal  macro  may be used for special characters, symbolic
       constants, and other syntactical items that should be typed exactly  as
       displayed.

             [1mUsage: .Li [22m⟨argument⟩ ...

                      [1m.Li \en          \n[0m
                      [1m.Li M1 M2 M3 ;   M1 M2 M3[22m;
                      [1m.Li cntrl-D ) ,  cntrl‐D[22m),
                      [1m.Li 1024 ...     1024 ...[0m

       The default width is 16n.

   [1mNames[0m
       The  ‘Nm’ macro is used for the document title or page topic.  Upon its
       first call, it has the peculiarity of remembering its  argument,  which
       should  always  be the topic of the man page.  When subsequently called
       without arguments, ‘Nm’ regurgitates this initial  name  for  the  sole
       purpose of making less work for the author.  Use of ‘Nm’ is also appro‐
       priate  when  presenting a command synopsis for the topic of a man page
       in section 1, 6, or 8.  Its behavior changes when presented with  argu‐
       ments of various forms.

                      [1m.Nm groff_mdoc  groff_mdoc[0m
                      [1m.Nm             groff_mdoc[0m
                      [1m.Nm \-mdoc      -mdoc[0m
                      [1m.Nm foo ) ) ,   foo[22m)),
                      [1m.Nm :           groff_mdoc[22m:

       By  default,  the  topic is set in boldface to reflect its prime impor‐
       tance in the discussion.  Cross references to  other  man  page  topics
       should use ‘Xr’; including a second argument for the section number en‐
       ables  them to be hyperlinked.  By default, cross‐referenced topics are
       set in italics to avoid cluttering the page with boldface.

       The default width is 10n.

   [1mOptions[0m
       The ‘.Op’ macro places option brackets around any  remaining  arguments
       on  the  command  line, and places any trailing punctuation outside the
       brackets.  The macros ‘.Oo’ and ‘.Oc’ (which produce an opening  and  a
       closing  option  bracket,  respectively) may be used across one or more
       lines or to specify the exact position of the closing parenthesis.

             [1mUsage: .Op [22m[⟨option⟩] ...

                      [1m.Op                                [22m[]
                      [1m.Op Fl k                           [22m[[1m-k[22m]
                      [1m.Op Fl k ) .                       [22m[[1m-k[22m]).
                      [1m.Op Fl k Ar kookfile               [22m[[1m-k [4m[22mkookfile[24m]
                      [1m.Op Fl k Ar kookfile ,             [22m[[1m-k [4m[22mkookfile[24m],
                      [1m.Op Ar objfil Op Ar corfil         [22m[[4mobjfil[24m [[4mcorfil[24m]]
                      [1m.Op Fl c Ar objfil Op Ar corfil ,  [22m[[1m-c [4m[22mobjfil[24m [[4mcorfil[24m]],
                      [1m.Op word1 word2                    [22m[word1 word2]
                      [1m.Li .Op Oo Ao option Ac Oc ...     .Op [22m[⟨option⟩] ...

       Here a typical example of the ‘.Oo’ and ‘.Oc’ macros:

             .Oo
             .Op Fl k Ar kilobytes
             .Op Fl i Ar interval
             .Op Fl c Ar count
             .Oc

       Produces:

             [[[1m-k [4m[22mkilobytes[24m] [[1m-i [4m[22minterval[24m] [[1m-c [4m[22mcount[24m]]

       The default width values of ‘.Op’ and ‘.Oo’ are 14n  and  10n,  respec‐
       tively.

   [1mPathnames[0m
       The  ‘.Pa’  macro formats file specifications.  If called without argu‐
       ments, ‘[4m~[24m’ (recognized by many  shells)  is  output,  representing  the
       user’s home directory.

             [1mUsage: .Pa [22m[⟨pathname⟩] ...

                      [1m.Pa                    [4m[22m~[0m
                      [1m.Pa /usr/share         [4m[22m/usr/share[0m
                      [1m.Pa /tmp/fooXXXXX ) .  [4m[22m/tmp/fooXXXXX[24m).

       The default width is 32n.

   [1mStandards[0m
       The  ‘.St’  macro  replaces  standard  abbreviations  with their formal
       names.

             [1mUsage: .St [22m⟨abbreviation⟩ ...

       Available pairs for “Abbreviation/Formal Name” are:

       ANSI/ISO C

             [1m-ansiC          [22mANSI X3.159‐1989 (“ANSI C89”)
             [1m-ansiC-89       [22mANSI X3.159‐1989 (“ANSI C89”)
             [1m-isoC           [22mISO/IEC 9899:1990 (“ISO C90”)
             [1m-isoC-90        [22mISO/IEC 9899:1990 (“ISO C90”)
             [1m-isoC-99        [22mISO/IEC 9899:1999 (“ISO C99”)
             [1m-isoC-2011      [22mISO/IEC 9899:2011 (“ISO C11”)

       POSIX Part 1: System API

             [1m-iso9945-1-90   [22mISO/IEC 9945‐1:1990 (“POSIX.1”)
             [1m-iso9945-1-96   [22mISO/IEC 9945‐1:1996 (“POSIX.1”)
             [1m-p1003.1        [22mIEEE Std 1003.1 (“POSIX.1”)
             [1m-p1003.1-88     [22mIEEE Std 1003.1‐1988 (“POSIX.1”)
             [1m-p1003.1-90     [22mISO/IEC 9945‐1:1990 (“POSIX.1”)
             [1m-p1003.1-96     [22mISO/IEC 9945‐1:1996 (“POSIX.1”)
             [1m-p1003.1b-93    [22mIEEE Std 1003.1b‐1993 (“POSIX.1”)
             [1m-p1003.1c-95    [22mIEEE Std 1003.1c‐1995 (“POSIX.1”)
             [1m-p1003.1g-2000  [22mIEEE Std 1003.1g‐2000 (“POSIX.1”)
             [1m-p1003.1i-95    [22mIEEE Std 1003.1i‐1995 (“POSIX.1”)
             [1m-p1003.1-2001   [22mIEEE Std 1003.1‐2001 (“POSIX.1”)
             [1m-p1003.1-2004   [22mIEEE Std 1003.1‐2004 (“POSIX.1”)
             [1m-p1003.1-2008   [22mIEEE Std 1003.1‐2008 (“POSIX.1”)

       POSIX Part 2: Shell and Utilities

             [1m-iso9945-2-93   [22mISO/IEC 9945‐2:1993 (“POSIX.2”)
             [1m-p1003.2        [22mIEEE Std 1003.2 (“POSIX.2”)
             [1m-p1003.2-92     [22mIEEE Std 1003.2‐1992 (“POSIX.2”)
             [1m-p1003.2a-92    [22mIEEE Std 1003.2a‐1992 (“POSIX.2”)

       X/Open

             [1m-susv1          [22mVersion  1  of  the  Single  UNIX   Specification
                             (“SUSv1”)
             [1m-susv2          [22mVersion   2  of  the  Single  UNIX  Specification
                             (“SUSv2”)
             [1m-susv3          [22mVersion  3  of  the  Single  UNIX   Specification
                             (“SUSv3”)
             [1m-susv4          [22mVersion   4  of  the  Single  UNIX  Specification
                             (“SUSv4”)
             [1m-svid4          [22mSystem V  Interface  Definition,  Fourth  Edition
                             (“SVID4”)
             [1m-xbd5           [22mX/Open Base Definitions Issue 5 (“XBD5”)
             [1m-xcu5           [22mX/Open Commands and Utilities Issue 5 (“XCU5”)
             [1m-xcurses4.2     [22mX/Open Curses Issue 4, Version 2 (“XCURSES4.2”)
             [1m-xns5           [22mX/Open Networking Services Issue 5 (“XNS5”)
             [1m-xns5.2         [22mX/Open Networking Services Issue 5.2 (“XNS5.2”)
             [1m-xpg3           [22mX/Open Portability Guide Issue 3 (“XPG3”)
             [1m-xpg4           [22mX/Open Portability Guide Issue 4 (“XPG4”)
             [1m-xpg4.2         [22mX/Open  Portability  Guide  Issue  4,  Version  2
                             (“XPG4.2”)
             [1m-xsh5           [22mX/Open System  Interfaces  and  Headers  Issue  5
                             (“XSH5”)

       Miscellaneous

             [1m-ieee754        [22mIEEE Std 754‐1985
             [1m-iso8601        [22mISO 8601
             [1m-iso8802-3      [22mISO/IEC 8802‐3:1989

   [1mVariable Types[0m
       The  ‘.Vt’  macro may be used whenever a type is referenced.  In a sec‐
       tion titled “Synopsis”, ‘Vt’ causes a break  (useful  for  old‐style  C
       variable declarations).

             [1mUsage: .Vt [22m⟨type⟩ ...

                      [1m.Vt extern char *optarg ;  [4m[22mextern[24m [4mchar[24m [4m*optarg[24m;
                      [1m.Vt FILE *                 [4m[22mFILE[24m [4m*[0m

   [1mVariables[0m
       Generic variable reference.

             [1mUsage: .Va [22m⟨variable⟩ ...

                      [1m.Va count             [4m[22mcount[0m
                      [1m.Va settimer ,        [4m[22msettimer[24m,
                      [1m.Va "int *prt" ) :    [4m[22mint[24m [4m*prt[24m):
                      [1m.Va "char s" ] ) ) ,  [4m[22mchar[24m [4ms[24m])),

       The default width is 12n.

   [1mManual Page Cross References[0m
       The  ‘.Xr’  macro  expects the first argument to be a manual page name.
       The optional second argument, if a string  (defining  the  manual  sec‐
       tion), is put into parentheses.

             [1mUsage: .Xr [22m⟨man page name⟩ [⟨section⟩] ...

                      [1m.Xr mdoc        [4m[22mmdoc[0m
                      [1m.Xr mdoc ,      [4m[22mmdoc[24m,
                      [1m.Xr mdoc 7      [4m[22mmdoc[24m(7)
                      [1m.Xr xinit 1x ;  [4m[22mxinit[24m(1x);

       The default width is 10n.

[1mGeneral text domain[0m
   [1mAT&T Macro[0m
             [1mUsage: .At [22m[⟨version⟩] ...

                      [1m.At       [22mAT&T UNIX
                      [1m.At v6 .  [22mVersion 6 AT&T UNIX.

       The following values for ⟨version⟩ are possible:

             [1m32v, v1, v2, v3, v4, v5, v6, v7, III, V, V.1, V.2, V.3, V.4[0m

   [1mBSD Macro[0m
             [1mUsage: .Bx [22m{-alpha | -beta | -devel} ...
                    [1m.Bx [22m[⟨version⟩ [⟨release⟩]] ...

                      [1m.Bx         [22mBSD
                      [1m.Bx 4.3 .   [22m4.3BSD.
                      [1m.Bx -devel  [22mBSD (currently under development)

       ⟨version⟩  will be prepended to the string ‘BSD’.  The following values
       for ⟨release⟩ are possible:

             [1mReno, reno, Tahoe, tahoe, Lite, lite, Lite2, lite2[0m

   [1mNetBSD Macro[0m
             [1mUsage: .Nx [22m[⟨version⟩] ...

                      [1m.Nx        [22mNetBSD
                      [1m.Nx 1.4 .  [22mNetBSD 1.4.

       For possible values of ⟨version⟩ see the description of the ‘.Os’  com‐
       mand above in section “Title macros”.

   [1mFreeBSD Macro[0m
             [1mUsage: .Fx [22m[⟨version⟩] ...

                      [1m.Fx        [22mFreeBSD
                      [1m.Fx 2.2 .  [22mFreeBSD 2.2.

       For  possible values of ⟨version⟩ see the description of the ‘.Os’ com‐
       mand above in section “Title macros”.

   [1mDragonFly Macro[0m
             [1mUsage: .Dx [22m[⟨version⟩] ...

                      [1m.Dx        [22mDragonFly
                      [1m.Dx 1.4 .  [22mDragonFly 1.4.

       For possible values of ⟨version⟩ see the description of the ‘.Os’  com‐
       mand above in section “Title macros”.

   [1mOpenBSD Macro[0m
             [1mUsage: .Ox [22m[⟨version⟩] ...

                      [1m.Ox 1.0  [22mOpenBSD 1.0

   [1mBSD/OS Macro[0m
             [1mUsage: .Bsx [22m[⟨version⟩] ...

                      [1m.Bsx 1.0  [22mBSD/OS 1.0

   [1mUnix Macro[0m
             [1mUsage: .Ux ...[0m

                      [1m.Ux  [22mUnix

   [1mEmphasis Macro[0m
       Text  may  be  stressed  or emphasized with the ‘.Em’ macro.  The usual
       font for emphasis is italic.

             [1mUsage: .Em [22m⟨argument⟩ ...

                      [1m.Em does not          [4m[22mdoes[24m [4mnot[0m
                      [1m.Em exceed 1024 .     [4m[22mexceed[24m [4m1024[24m.
                      [1m.Em vide infra ) ) ,  [4m[22mvide[24m [4minfra[24m)),

       The default width is 10n.

   [1mFont Mode[0m
       The ‘.Bf’ font mode must be ended with  the  ‘.Ef’  macro  (the  latter
       takes no arguments).  Font modes may be nested within other font modes.

       ‘.Bf’ has the following syntax:

             [1m.Bf [22m⟨font mode⟩

       ⟨font mode⟩ must be one of the following three types:

             [1mEm [22m| [1m-emphasis  [22mSame  as  if the ‘.Em’ macro was used for the en‐
                             tire block of text.
             [1mLi [22m| [1m-literal   [22mSame as if the ‘.Li’ macro was used for  the  en‐
                             tire block of text.
             [1mSy [22m| [1m-symbolic  [22mSame  as  if the ‘.Sy’ macro was used for the en‐
                             tire block of text.

       Both macros are neither callable nor parsed.

   [1mEnclosure and Quoting Macros[0m
       The concept of enclosure is similar to quoting.  The  object  being  to
       enclose one or more strings between a pair of characters like quotes or
       parentheses.   The terms quoting and enclosure are used interchangeably
       throughout this document.  Most of the one‐line enclosure macros end in
       small letter ‘q’ to give a hint of quoting, but there are a few irregu‐
       larities.  For each enclosure macro, there is a  pair  of  opening  and
       closing  macros that end with the lowercase letters ‘o’ and ‘c’ respec‐
       tively.

       [1mQuote   Open   Close   Function                  Result[0m
       .Aq     .Ao    .Ac     Angle Bracket Enclosure   <string>
       .Bq     .Bo    .Bc     Bracket Enclosure         [string]
       .Brq    .Bro   .Brc    Brace Enclosure           {string}
       .Dq     .Do    .Dc     Double Quote              “string”
       .Eq     .Eo    .Ec     Enclose String (in XY)    XstringY
       .Pq     .Po    .Pc     Parenthesis Enclosure     (string)
       .Ql                    Quoted Literal            “string” or string
       .Qq     .Qo    .Qc     Straight Double Quote     "string"
       .Sq     .So    .Sc     Single Quote              ‘string’

       All macros ending with ‘q’ and ‘o’ have a default width value of 12n.

       [1m.Eo[22m, [1m.Ec  [22mThese macros expect the first argument to be the opening  and
                 closing strings, respectively.

       [1m.Es[22m, [1m.En  [22mTo  work around the nine‐argument limit in the original [4mtroff[0m
                 program, [4mmdoc[24m supports two other macros that  are  now  obso‐
                 lete.   ‘.Es’ uses its first and second parameters as opening
                 and closing marks which are then used to  enclose  the  argu‐
                 ments  of  ‘.En’.   The  default  width value is 12n for both
                 macros.

       [1m.Eq       [22mThe first and second arguments of this macro are the  opening
                 and  closing  strings respectively, followed by the arguments
                 to be enclosed.

       [1m.Ql       [22mThe quoted literal macro behaves  differently  in  [4mtroff[24m  and
                 [4mnroff[24m modes.  If formatted with [4mnroff[24m(1), a quoted literal is
                 always  quoted.   If  formatted  with  [4mtroff[24m, an item is only
                 quoted if the width of the item is less than three  constant‐
                 width characters.  This is to make short strings more visible
                 where the font change to literal (constant‐width) is less no‐
                 ticeable.

                 The default width is 16n.

       [1m.Pf       [22mThe  prefix macro suppresses the whitespace between its first
                 and second argument:

                       [1m.Pf ( Fa name2  [22m([4mname2[0m

                 The default width is 12n.

                 The ‘.Ns’ macro (see below)  performs  the  analogous  suffix
                 function.

       [1m.Ap       [22mThe  ‘.Ap’  macro inserts an apostrophe and exits any special
                 text modes, continuing in ‘.No’ mode.

       Examples of quoting:

             [1m.Aq                      [22m⟨⟩
             [1m.Aq Pa ctype.h ) ,       [22m⟨[4mctype.h[24m⟩),
             [1m.Bq                      [22m[]
             [1m.Bq Em Greek , French .  [22m[[4mGreek[24m, [4mFrench[24m].
             [1m.Dq                      [22m“”
             [1m.Dq string abc .         [22m“string abc”.
             [1m.Dq '\[ha][A-Z]'         [22m“’^[A‐Z]’”
             [1m.Ql man mdoc             [22m‘man mdoc’
             [1m.Qq                      [22m""
             [1m.Qq string ) ,           [22m"string"),
             [1m.Qq string Ns ),         [22m"string),"
             [1m.Sq                      [22m‘’
             [1m.Sq string               [22m‘string’
             [1m.Em or Ap ing            [4m[22mor[24m’ing

       For a good example of nested enclosure macros,  see  the  ‘.Op’  option
       macro.   It  was  created  from the same underlying enclosure macros as
       those presented in the list above.  The ‘.Xo’ and ‘.Xc’ extended  argu‐
       ment list macros are discussed below.

   [1mNormal text macro[0m
       ‘No’ formats subsequent argument(s) normally, ending the effect of ‘Em’
       and  similar.  Parsing is [4mnot[24m suppressed, so you must prefix words like
       ‘No’ with ‘\&’ to avoid their interpretation as [4mmdoc[24m macros.

             [1mUsage: .No [4m[22margument[24m ...

                      [1m.Em Use caution No here .  [22m→ [4mUse[24m [4mcaution[24m here.
                      [1m.Em No dogs allowed .      [22m→ [4mNo[24m dogs allowed.
                      [1m.Em \&No dogs allowed .    [22m→ [4mNo[24m [4mdogs[24m [4mallowed[24m.

       The default width is 12n.

   [1mNo‐Space Macro[0m
       The ‘.Ns’ macro suppresses insertion of a space between the current po‐
       sition and its first parameter.  For example,  it  is  useful  for  old
       style argument lists where there is no space between the flag and argu‐
       ment:

             [1mUsage: ... [22m⟨argument⟩ Ns [⟨argument⟩] ...
                    [1m.Ns [22m⟨argument⟩ ...

                      [1m.Op Fl I Ns Ar directory  [22m[[1m-I[4m[22mdirectory[24m]

       Note:  The ‘.Ns’ macro always invokes the ‘.No’ macro after eliminating
       the space unless another macro name follows it.  If used as  a  command
       (i.e.,  the  second form above in the ‘Usage’ line), ‘.Ns’ is identical
       to ‘.No’.

   [1m(Sub)section cross references[0m
       Use the ‘.Sx’ macro to cite a (sub)section  heading  within  the  given
       document.

             [1mUsage: .Sx [22m⟨section‐reference⟩ ...

                      [1m.Sx Files  [22m→ “Files”

       The default width is 16n.

   [1mSymbolics[0m
       The symbolic emphasis macro is generally a boldface macro in either the
       symbolic sense or the traditional English usage.

             [1mUsage: .Sy [22m⟨symbol⟩ ...

                      [1m.Sy Important Notice  [22m→ [1mImportant Notice[0m

       The default width is 6n.

   [1mMathematical Symbols[0m
       Use this macro for mathematical symbols and similar things.

             [1mUsage: .Ms [22m⟨math symbol⟩ ...

                      [1m.Ms sigma  [22m→ [1msigma[0m

       The default width is 6n.

   [1mReferences and Citations[0m
       The  following  macros  make a modest attempt to handle references.  At
       best, the macros make it convenient to manually drop  in  a  subset  of
       [4mrefer[24m(1) style references.

             [1m.Rs     [22mReference  start (does not take arguments).  In a section
                     titled “See also”, it causes a break and  begins  collec‐
                     tion  of  reference  information  until the reference end
                     macro is read.
             [1m.Re     [22mReference end (does not take arguments).   The  reference
                     is printed.
             [1m.%A     [22mReference author name; one name per invocation.
             [1m.%B     [22mBook title.
             [1m.%C     [22mCity/place.
             [1m.%D     [22mDate.
             [1m.%I     [22mIssuer/publisher name.
             [1m.%J     [22mJournal name.
             [1m.%N     [22mIssue number.
             [1m.%O     [22mOptional information.
             [1m.%P     [22mPage number.
             [1m.%Q     [22mCorporate or foreign author.
             [1m.%R     [22mReport name.
             [1m.%T     [22mTitle of article.
             [1m.%U     [22mOptional hypertext reference.
             [1m.%V     [22mVolume.

       Macros  beginning  with  ‘%’ are not callable but accept multiple argu‐
       ments in the usual way.  Only the ‘.Tn’ macro is handled properly as  a
       parameter; other macros will cause strange output.  ‘.%B’ and ‘.%T’ can
       be used outside of the ‘.Rs/.Re’ environment.

       Example:

             .Rs
             .%A "Matthew Bar"
             .%A "John Foo"
             .%T "Implementation Notes on foobar(1)"
             .%R "Technical Report ABC-DE-12-345"
             .%Q "Drofnats College"
             .%C "Nowhere"
             .%D "April 1991"
             .Re

       produces

             Matthew Bar and John Foo, [4mImplementation[24m [4mNotes[24m [4mon[24m [4mfoobar(1)[24m,
             Technical Report ABC‐DE‐12‐345, Drofnats College, Nowhere, April
             1991.

   [1mTrade Names or Acronyms[0m
       The  trade  name macro prints its arguments at a smaller type size.  It
       is intended to  imitate  a  small  caps  fonts  for  fully  capitalized
       acronyms.

             [1mUsage: .Tn [22m⟨symbol⟩ ...

                      [1m.Tn DEC    [22mDEC
                      [1m.Tn ASCII  [22mASCII

       The default width is 10n.

   [1mExtended Arguments[0m
       The  [1m.Xo [22mand [1m.Xc [22mmacros allow one to extend an argument list on a macro
       boundary for the ‘.It’ macro (see below).  Note that [1m.Xo  [22mand  [1m.Xc  [22mare
       implemented similarly to all other macros opening and closing an enclo‐
       sure  (without  inserting  characters, of course).  This means that the
       following is true for those macros also.

       Here is an example of ‘.Xo’ using the space mode macro to turn  spacing
       off:

             .Bd -literal -offset indent
             .Sm off
             .It Xo Sy I Ar operation
             .No \en Ar count No \en
             .Xc
             .Sm on
             .Ed

       produces

             [1mI[4m[22moperation[24m\n[4mcount[24m\n

       Another one:

             .Bd -literal -offset indent
             .Sm off
             .It Cm S No / Ar old_pattern Xo
             .No / Ar new_pattern
             .No / Op Cm g
             .Xc
             .Sm on
             .Ed

       produces

             [1mS[22m/[4mold_pattern[24m/[4mnew_pattern[24m/[[1mg[22m]

       Another  example  of  ‘.Xo’  and  enclosure macros: Test the value of a
       variable.

             .Bd -literal -offset indent
             .It Xo
             .Ic .ifndef
             .Oo \&! Oc Ns Ar variable Oo
             .Ar operator variable No ...
             .Oc Xc
             .Ed

       produces

             [1m.ifndef [22m[!][4mvariable[24m [[4moperator[24m [4mvariable[24m ...]

[1mPage structure domain[0m
   [1mSection headings[0m
       The following ‘.Sh’ section heading macros are required  in  every  man
       page.  The remaining section headings are recommended at the discretion
       of  the  author writing the manual page.  The ‘.Sh’ macro is parsed but
       not generally callable.  It can be used as an argument  in  a  call  to
       ‘.Sh’ only; it then reactivates the default font for ‘.Sh’.

       The default width is 8n.

       [1m.Sh Name           [22mThe  ‘.Sh  Name’  macro is mandatory.  If not speci‐
                          fied, headers, footers,  and  page  layout  defaults
                          will  not  be set and things will be rather unpleas‐
                          ant.  The [4mName[24m section consists of  at  least  three
                          items.  The first is the ‘.Nm’ name macro naming the
                          subject of the man page.  The second is the name de‐
                          scription  macro, ‘.Nd’, which separates the subject
                          name from the third item, which is the  description.
                          The  description  should be the most terse and lucid
                          possible, as the space available is small.

                          ‘.Nd’ first prints ‘-’, then all its arguments.

       [1m.Sh Library        [22mThis section is for section two and  three  function
                          calls.   It  should  consist of a single ‘.Lb’ macro
                          call; see “Library Names”.

       [1m.Sh Synopsis       [22mThe “Synopsis” section describes the  typical  usage
                          of  the  subject of a man page.  The macros required
                          are either ‘.Nm’,  ‘.Cd’,  or  ‘.Fn’  (and  possibly
                          ‘.Fo’,  ‘.Fc’, ‘.Fd’, and ‘.Ft’).  The function name
                          macro ‘.Fn’ is required for manual page  sections  2
                          and  3;  the command and general name macro ‘.Nm’ is
                          required for sections 1, 5, 6, 7, and 8.  Section  4
                          manuals require a ‘.Nm’, ‘.Fd’ or a ‘.Cd’ configura‐
                          tion  device  usage macro.  Several other macros may
                          be necessary to produce the synopsis line  as  shown
                          below:

                                [1mcat [22m[[1m-benstuv[22m] [[1m-[22m] [4mfile[24m ...

                          The following macros were used:

                                [1m.Nm cat[0m
                                [1m.Op Fl benstuv[0m
                                [1m.Op Fl[0m
                                [1m.Ar file No ...[0m

       [1m.Sh Description    [22mIn  most  cases  the first text in the “Description”
                          section is a brief paragraph on the  command,  func‐
                          tion  or file, followed by a lexical list of options
                          and respective explanations.  To create such a list,
                          the ‘.Bl’ (begin list), ‘.It’ (list item) and  ‘.El’
                          (end  list) macros are used (see “Lists and Columns”
                          below).

       [1m.Sh Implementation notes[0m
                          Implementation specific information should be placed
                          here.

       [1m.Sh Return values  [22mSections 2, 3 and 9 function return values should go
                          here.  The ‘.Rv’ macro may be used to generate  text
                          for use in the “Return values” section for most sec‐
                          tion 2 and 3 library functions; see “Return Values”.

       The  following  ‘.Sh’ section headings are part of the preferred manual
       page layout and must be used  appropriately  to  maintain  consistency.
       They are listed in the order in which they would be used.

       [1m.Sh Environment    [22mThe  [4mEnvironment[24m  section  should reveal any related
                          environment variables and clues  to  their  behavior
                          and/or usage.

       [1m.Sh Files          [22mFiles which are used or created by the man page sub‐
                          ject  should  be  listed  via the ‘.Pa’ macro in the
                          “Files” section.

       [1m.Sh Examples       [22mThere are several ways to create examples.  See sub‐
                          section “Examples and Displays” below for details.

       [1m.Sh Diagnostics    [22mDiagnostic messages from a command should be  placed
                          in  this  section.   The  ‘.Ex’ macro may be used to
                          generate text for use in the  “Diagnostics”  section
                          for  most  section  1,  6  and 8 commands; see “Exit
                          Status”.

       [1m.Sh Compatibility  [22mKnown compatibility issues (e.g. deprecated  options
                          or parameters) should be listed here.

       [1m.Sh Errors         [22mSpecific  error  handling,  especially  from library
                          functions (man page sections 2, 3, and 9) should  go
                          here.   The  ‘.Er’ macro is used to specify an error
                          (errno).

       [1m.Sh See also       [22mReferences to other material on the man  page  topic
                          and  cross  references  to  other relevant man pages
                          should be placed in the “See also”  section.   Cross
                          references  are  specified  using  the  ‘.Xr’ macro.
                          Currently [4mrefer[24m(1) style references are not accommo‐
                          dated.

                          It is  recommended  that  the  cross  references  be
                          sorted  by  section  number,  then alphabetically by
                          name within each section, then separated by  commas.
                          Example:

                          [4mls[24m(1), [4mps[24m(1), [4mgroup[24m(5), [4mpasswd[24m(5)

       [1m.Sh Standards      [22mIf the command, library function, or file adheres to
                          a  specific  implementation  such as IEEE Std 1003.2
                          (“POSIX.2”) or ANSI X3.159‐1989  (“ANSI  C89”)  this
                          should  be  noted here.  If the command does not ad‐
                          here to any standard, its history should be noted in
                          the [4mHistory[24m section.

       [1m.Sh History        [22mAny command which does not adhere  to  any  specific
                          standards  should  be  outlined historically in this
                          section.

       [1m.Sh Authors        [22mCredits should be placed here.  Use the ‘.An’  macro
                          for  names  and  the ‘.Aq’ macro for email addresses
                          within optional contact information.  Explicitly in‐
                          dicate whether the person authored the initial  man‐
                          ual  page  or the software or whatever the person is
                          being credited for.

       [1m.Sh Bugs           [22mBlatant problems with the topic go here.

       User‐specified ‘.Sh’ sections may be added; for example,  this  section
       was set with:

                      .Sh "Page structure domain"

   [1mSubsection headings[0m
       Subsection  headings  have exactly the same syntax as section headings:
       ‘.Ss’ is parsed but not generally callable.  It can be used as an argu‐
       ment in a call to ‘.Ss’ only; it then reactivates the default font  for
       ‘.Ss’.

       The default width is 8n.

   [1mParagraphs and Line Spacing[0m
       [1m.Pp  [22mThe  ‘.Pp’  paragraph  command may be used to specify a line space
            where necessary.  The macro is not  necessary  after  a  ‘.Sh’  or
            ‘.Ss’  macro or before a ‘.Bl’ or ‘.Bd’ macro (which both assert a
            vertical distance unless the [1m-compact [22mflag is given).

            The macro is neither callable nor parsed and takes  no  arguments;
            an alternative name is ‘.Lp’.

   [1mKeeps[0m
       The  only  keep  that  is  implemented  at this time is for words.  The
       macros are ‘.Bk’ (begin keep) and ‘.Ek’ (end keep).   The  only  option
       that  ‘.Bk’  currently  accepts is [1m-words [22m(also the default); this pre‐
       vents breaks in the middle of options.  In the example  for  [1mmake  [22mcom‐
       mand‐line  arguments  (see “What’s in a Name”), the keep prevents [4mnroff[0m
       from placing the flag and the argument on separate lines.

       Neither macro is callable or parsed.

       More work needs to be done on the keep macros;  specifically,  a  [1m-line[0m
       option should be added.

   [1mExamples and Displays[0m
       There are seven types of displays.

       [1m.D1  [22m(This  is  D‐one.)  Display one line of indented text.  This macro
            is parsed but not callable.

                  [1m-ldghfstru[0m

            The above was produced by: [1m.D1 Fl ldghfstru[22m.

       [1m.Dl  [22m(This is D‐ell.)  Display one line of indented [4mliteral[24m text.   The
            ‘.Dl’ example macro has been used throughout this file.  It allows
            the  indentation  (display) of one line of text.  Its default font
            is set to constant width  (literal).   ‘.Dl’  is  parsed  but  not
            callable.

                  [1m% ls -ldg /usr/local/bin[0m

            The above was produced by: [1m.Dl % ls \-ldg /usr/local/bin[22m.

       [1m.Bd  [22mBegin  display.   The  ‘.Bd’  display must be ended with the ‘.Ed’
            macro.  It has the following syntax:

                  [1m.Bd [22m{-literal | -filled | -unfilled | -ragged | -centered}
                       [-offset ⟨string⟩] [-file ⟨file name⟩] [-compact]

            [1m-ragged            [22mFill, but do not adjust the right margin  (only
                               left‐justify).
            [1m-centered          [22mCenter lines between the current left and right
                               margin.   Note  that  each  single line is cen‐
                               tered.
            [1m-unfilled          [22mDo not fill;  break  lines  where  their  input
                               lines  are  broken.   This can produce overlong
                               lines without warning messages.
            [1m-filled            [22mDisplay a filled block.  The block of  text  is
                               formatted  (i.e., the text is justified on both
                               the left and right side).
            [1m-literal           [22mDisplay block with literal font (usually fixed‐
                               width).   Useful  for  source  code  or  simple
                               tabbed or spaced text.
            [1m-file [22m⟨[4mfile[24m [4mname[24m⟩  The  file  whose name follows the [1m-file [22mflag is
                               read and displayed  before  any  data  enclosed
                               with  ‘.Bd’  and ‘.Ed’, using the selected dis‐
                               play type.  Any [4mtroff/mdoc[24m commands in the file
                               will be processed.
            [1m-offset [22m⟨[4mstring[24m⟩   If [1m-offset [22mis specified with one of the follow‐
                               ing strings, the string is interpreted to indi‐
                               cate the level of indentation for the forthcom‐
                               ing block of text:

                               [4mleft[24m        Align block  on  the  current  left
                                           margin; this is the default mode of
                                           ‘.Bd’.
                               [4mcenter[24m      Supposedly  center  the  block.  At
                                           this time unfortunately, the  block
                                           merely  gets  left aligned about an
                                           imaginary center margin.
                               [4mindent[24m      Indent by one default indent  value
                                           or  tab.   The default indent value
                                           is also  used  for  the  ‘.D1’  and
                                           ‘.Dl’  macros, so one is guaranteed
                                           the two types of displays will line
                                           up.  The indentation value is  nor‐
                                           mally set to 6n or about two thirds
                                           of  an  inch  (six  constant  width
                                           characters).
                               [4mindent-two[24m  Indent two times the default indent
                                           value.
                               [4mright[24m       This [4mleft[24m aligns  the  block  about
                                           two  inches  from the right side of
                                           the page.  This  macro  needs  work
                                           and  perhaps may never do the right
                                           thing within [4mtroff[24m.

                               If ⟨string⟩ is a valid numeric  expression  in‐
                               stead  ([4mwith[24m  [4ma[24m  [4mscaling[24m  [4mindicator[24m  [4mother[24m [4mthan[0m
                               ‘[4mu[24m’), use that value for indentation.  The most
                               useful scaling  indicators  are  ‘m’  and  ‘n’,
                               specifying  the  so‐called  [4mEm[24m  and  [4mEn[24m [4msquare[24m.
                               This is approximately the width of the  letters
                               ‘m’  and  ‘n’  respectively of the current font
                               (for [4mnroff[24m output, both scaling indicators give
                               the same values).  If ⟨string⟩ isn’t a  numeric
                               expression,  it is tested whether it is an [4mmdoc[0m
                               macro name, and the default offset value  asso‐
                               ciated  with  this  macro is used.  Finally, if
                               all tests fail, the width of ⟨string⟩  (typeset
                               with  a  fixed‐width font) is taken as the off‐
                               set.
            [1m-compact           [22mSuppress insertion of vertical space before be‐
                               gin of display.

       [1m.Ed  [22mEnd display (takes no arguments).

   [1mLists and Columns[0m
       There are several types of lists which may be initiated with the  ‘.Bl’
       begin‐list  macro.   Items within the list are specified with the ‘.It’
       item macro, and each list must end with the ‘.El’ macro.  Lists may  be
       nested  within  themselves and within displays.  The use of columns in‐
       side of lists or lists inside of columns is untested.

       In addition, several list attributes may be specified such as the width
       of a tag, the list offset, and compactness (blank lines  between  items
       allowed  or disallowed).  Most of this document has been formatted with
       a tag style list ([1m-tag[22m).

       It has the following syntax forms:

             [1m.Bl [22m{-hang | -ohang | -tag | -diag | -inset} [-width ⟨string⟩]
                  [-offset ⟨string⟩] [-compact]
             [1m.Bl [22m-column [-offset ⟨string⟩] ⟨string1⟩ ⟨string2⟩ ...
             [1m.Bl [22m{-item | -enum [-nested] | -bullet | -hyphen | -dash}
                  [-offset ⟨string⟩] [-compact]

       And now a detailed description of the list types.

       [1m-bullet  [22mA bullet list.

                      .Bl -bullet -offset indent -compact
                      .It
                      Bullet one goes here.
                      .It
                      Bullet two here.
                      .El

                Produces:

                      [1m•   [22mBullet one goes here.
                      [1m•   [22mBullet two here.

       [1m-dash [22m(or [1m-hyphen[22m)
                A dash list.

                      .Bl -dash -offset indent -compact
                      .It
                      Dash one goes here.
                      .It
                      Dash two here.
                      .El

                Produces:

                      [1m-   [22mDash one goes here.
                      [1m-   [22mDash two here.

       [1m-enum    [22mAn enumerated list.

                      .Bl -enum -offset indent -compact
                      .It
                      Item one goes here.
                      .It
                      And item two here.
                      .El

                The result:

                      1.   Item one goes here.
                      2.   And item two here.

                If you want to nest enumerated lists,  use  the  [1m-nested  [22mflag
                (starting with the second‐level list):

                      .Bl -enum -offset indent -compact
                      .It
                      Item one goes here
                      .Bl -enum -nested -compact
                      .It
                      Item two goes here.
                      .It
                      And item three here.
                      .El
                      .It
                      And item four here.
                      .El

                Result:

                      1.   Item one goes here.
                           1.1.   Item two goes here.
                           1.2.   And item three here.
                      2.   And item four here.

       [1m-item    [22mA list of type [1m-item [22mwithout list markers.

                      .Bl -item -offset indent
                      .It
                      Item one goes here.
                      Item one goes here.
                      Item one goes here.
                      .It
                      Item two here.
                      Item two here.
                      Item two here.
                      .El

                Produces:

                      Item  one goes here.  Item one goes here.  Item one goes
                      here.

                      Item two here.  Item two here.  Item two here.

       [1m-tag     [22mA list with tags.  Use [1m-width [22mto specify the tag width.

                      SL    sleep time of the process (seconds blocked)
                      PAGEIN
                            number of disk I/O operations resulting from  ref‐
                            erences  by  the  process  to  pages not loaded in
                            core.
                      UID   numerical user‐id of process owner
                      PPID  numerical id of parent of process  priority  (non‐
                            positive when in non‐interruptible wait)

                The raw text:

                      .Bl -tag -width "PPID" -compact -offset indent
                      .It SL
                      sleep time of the process (seconds blocked)
                      .It PAGEIN
                      number of disk I/O operations resulting from references
                      by the process to pages not loaded in core.
                      .It UID
                      numerical user-id of process owner
                      .It PPID
                      numerical id of parent of process priority
                      (non-positive when in non-interruptible wait)
                      .El

       [1m-diag    [22mDiag  lists create section four diagnostic lists and are simi‐
                lar to inset lists except callable macros  are  ignored.   The
                [1m-width [22mflag is not meaningful in this context.

                Example:

                      .Bl -diag
                      .It You can’t use Sy here.
                      The message says all.
                      .El

                produces

                [1mYou can’t use Sy here.  [22mThe message says all.

       [1m-hang    [22mA list with hanging tags.

                      [4mHanged[24m  labels  appear  similar to tagged lists when the
                              label is smaller than the label width.

                      [4mLonger[24m [4mhanged[24m [4mlist[24m [4mlabels[24m blend into the  paragraph  un‐
                              like tagged paragraph labels.

                And the unformatted text which created it:

                      .Bl -hang -offset indent
                      .It Em Hanged
                      labels appear similar to tagged lists when the
                      label is smaller than the label width.
                      .It Em Longer hanged list labels
                      blend into the paragraph unlike
                      tagged paragraph labels.
                      .El

       [1m-ohang   [22mLists  with  overhanging  tags  do not use indentation for the
                items; tags are written to a separate line.

                      [1mSL[0m
                      sleep time of the process (seconds blocked)

                      [1mPAGEIN[0m
                      number of disk I/O operations resulting from  references
                      by the process to pages not loaded in core.

                      [1mUID[0m
                      numerical user‐id of process owner

                      [1mPPID[0m
                      numerical id of parent of process priority (non‐positive
                      when in non‐interruptible wait)

                The raw text:

                      .Bl -ohang -offset indent
                      .It Sy SL
                      sleep time of the process (seconds blocked)
                      .It Sy PAGEIN
                      number of disk I/O operations resulting from references
                      by the process to pages not loaded in core.
                      .It Sy UID
                      numerical user-id of process owner
                      .It Sy PPID
                      numerical id of parent of process priority
                      (non-positive when in non-interruptible wait)
                      .El

       [1m-inset   [22mHere is an example of inset labels:

                      [4mTag[24m  The tagged list (also called a tagged paragraph) is
                      the most common type of list used in the Berkeley  manu‐
                      als.  Use a [1m-width [22mattribute as described below.

                      [4mDiag[24m Diag lists create section four diagnostic lists and
                      are  similar  to  inset lists except callable macros are
                      ignored.

                      [4mHang[24m Hanged labels are a matter of taste.

                      [4mOhang[24m Overhanging labels are nice  when  space  is  con‐
                      strained.

                      [4mInset[24m  Inset labels are useful for controlling blocks of
                      paragraphs and are valuable for converting [4mmdoc[24m  manuals
                      to other formats.

                Here is the source text which produced the above example:

                      .Bl -inset -offset indent
                      .It Em Tag
                      The tagged list (also called a tagged paragraph)
                      is the most common type of list used in the
                      Berkeley manuals.
                      .It Em Diag
                      Diag lists create section four diagnostic lists
                      and are similar to inset lists except callable
                      macros are ignored.
                      .It Em Hang
                      Hanged labels are a matter of taste.
                      .It Em Ohang
                      Overhanging labels are nice when space is constrained.
                      .It Em Inset
                      Inset labels are useful for controlling blocks of
                      paragraphs and are valuable for converting
                      .Xr mdoc
                      manuals to other formats.
                      .El

       [1m-column  [22mThis  list  type  generates  multiple  columns.  The number of
                columns and the width of each column is determined by the  ar‐
                guments  to  the  [1m-column [22mlist, ⟨[4mstring1[24m⟩, ⟨[4mstring2[24m⟩, etc.  If
                ⟨[4mstringN[24m⟩ starts with a ‘.’ (dot) immediately  followed  by  a
                valid  [4mmdoc[24m  macro name, interpret ⟨[4mstringN[24m⟩ and use the width
                of the result.  Otherwise, the  width  of  ⟨[4mstringN[24m⟩  (typeset
                with a fixed‐width font) is taken as the [4mN[24mth column width.

                Each  ‘.It’  argument  is  parsed  to  make a row, each column
                within the row is a separate argument separated by  a  tab  or
                the ‘.Ta’ macro.

                The table:

                      [1mString    Nroff    Troff[0m
                      [1m<=        [22m<=       ≤
                      [1m>=        [22m>=       ≥

                was produced by:

                .Bl -column -offset indent ".Sy String" ".Sy Nroff" ".Sy Troff"
                .It Sy String Ta Sy Nroff Ta Sy Troff
                .It Li <= Ta <= Ta \*(<=
                .It Li >= Ta >= Ta \*(>=
                .El

                Don’t  abuse  this  list  type!  For more complicated cases it
                might be far better and easier to use [4mtbl[24m(1), the  table  pre‐
                processor.

       Other keywords:

       [1m-width [22m⟨[4mstring[24m⟩   If  ⟨[4mstring[24m⟩ starts with a ‘.’ (dot) immediately fol‐
                         lowed by a valid [4mmdoc[24m macro name, interpret  ⟨[4mstring[24m⟩
                         and use the width of the result.  Almost all lists in
                         this document use this option.

                         Example:

                               .Bl -tag -width ".Fl test Ao Ar string Ac"
                               .It Fl test Ao Ar string Ac
                               This is a longer sentence to show how the
                               .Fl width
                               flag works in combination with a tag list.
                               .El

                         gives:

                         [1m-test [22m⟨[4mstring[24m⟩  This is a longer sentence to show how
                                         the  [1m-width [22mflag works in combination
                                         with a tag list.

                         (Note that the current state of [4mmdoc[24m is saved  before
                         ⟨[4mstring[24m⟩  is  interpreted;  afterwards, all variables
                         are restored again.  However, boxes (used for  enclo‐
                         sures)  can’t  be  saved in GNU [4mtroff[24m(1); as a conse‐
                         quence, arguments must always be  [4mbalanced[24m  to  avoid
                         nasty  errors.   For  example,  do  not write ‘.Ao Ar
                         string’ but ‘.Ao Ar string Xc’ instead if you  really
                         need only an opening angle bracket.)

                         Otherwise,  if ⟨[4mstring[24m⟩ is a valid numeric expression
                         ([4mwith[24m [4ma[24m [4mscaling[24m [4mindicator[24m [4mother[24m [4mthan[24m ‘[4mu[24m’),  use  that
                         value for indentation.  The most useful scaling indi‐
                         cators  are  ‘m’ and ‘n’, specifying the so‐called [4mEm[0m
                         and [4mEn[24m [4msquare[24m.  This is approximately  the  width  of
                         the  letters  ‘m’ and ‘n’ respectively of the current
                         font (for [4mnroff[24m output, both scaling indicators  give
                         the  same  values).   If ⟨[4mstring[24m⟩ isn’t a numeric ex‐
                         pression, it is tested whether it is  an  [4mmdoc[24m  macro
                         name,  and  the  default  width value associated with
                         this macro is used.  Finally, if all tests fail,  the
                         width  of  ⟨[4mstring[24m⟩ (typeset with a fixed‐width font)
                         is taken as the width.

                         If a width is not specified for the  tag  list  type,
                         ‘6n’ is used.

       [1m-offset [22m⟨[4mstring[24m⟩  If  ⟨[4mstring[24m⟩  is [4mindent[24m, a default indent value (nor‐
                         mally set to 6n, similar to the value used  in  ‘.Dl’
                         or  ‘.Bd’)  is  used.  If ⟨[4mstring[24m⟩ is a valid numeric
                         expression instead ([4mwith[24m [4ma[24m  [4mscaling[24m  [4mindicator[24m  [4mother[0m
                         [4mthan[24m  ‘[4mu[24m’), use that value for indentation.  The most
                         useful scaling indicators are ‘m’ and ‘n’, specifying
                         the so‐called [4mEm[24m and [4mEn[24m  [4msquare[24m.   This  is  approxi‐
                         mately  the  width of the letters ‘m’ and ‘n’ respec‐
                         tively of the current font (for  [4mnroff[24m  output,  both
                         scaling   indicators   give  the  same  values).   If
                         ⟨[4mstring[24m⟩ isn’t a numeric  expression,  it  is  tested
                         whether  it  is  an  [4mmdoc[24m macro name, and the default
                         offset value associated with this macro is used.  Fi‐
                         nally, if all  tests  fail,  the  width  of  ⟨[4mstring[24m⟩
                         (typeset  with  a  fixed‐width  font) is taken as the
                         offset.

       [1m-compact          [22mSuppress insertion of vertical space before the  list
                         and between list items.

[1mMiscellaneous macros[0m
       A double handful of macros fit only uncomfortably into one of the above
       sections.   Of  these,  we  couldn’t find attested examples for ‘Me’ or
       ‘Ot’.  They are documented here  for  completeness—if  you  know  their
       proper  usage, please send a mail to [4mgroff@gnu.org[24m and include a speci‐
       men with its provenance.

       [1m.Bt  [22mformats boilerplate text.

                  [1m.Bt  [22m→ is currently in beta test.

            It is neither callable nor parsed and takes no arguments.  Its de‐
            fault width is 6n.

       [1m.Fr  [22mis an obsolete means of specifying a function return value.

                  Usage: .[1mFr [4m[22mreturn‐value[24m ...

            ‘Fr’ allows a break right before the return value (usually a  sin‐
            gle digit) which is bad typographical behaviour.  Instead, set the
            return  value with the rest of the code, using ‘\~’ to tie the re‐
            turn value to the previous word.

            Its default width is 12n.

       [1m.Hf  [22mInlines the contents of a (header) file into the document.

                  Usage: .[1mHf [4m[22mfile[0m

            It first prints ‘File:’ followed by the file name, then  the  con‐
            tents of [4mfile[24m.  It is neither callable nor parsed.

       [1m.Lk  [22mEmbed hyperlink.

                  Usage: .[1mLk [4m[22muri[24m [[4mlink‐text[24m]

            Its default width is 6n.

       [1m.Me  [22mUsage  unknown.  The [4mmdoc[24m sources describe it as a macro for “menu
            entries”.

            Its default width is 6n.

       [1m.Mt  [22mEmbed email address.

                  Usage: .[1mMt [4m[22memail‐address[0m

            Its default width is 6n.

       [1m.Ot  [22mUsage unknown.  The [4mmdoc[24m sources describe it as “old function type
            (fortran)”.

       [1m.Sm  [22mManipulate or toggle argument‐spacing mode.

                  Usage: .[1mSm [22m[[1mon [22m| [1moff[22m] ...

            If argument‐spacing mode is off, no spaces between macro arguments
            are inserted.  If called without a parameter (or if the next para‐
            meter is neither ‘on’ nor ‘off’),  ‘Sm’  toggles  argument‐spacing
            mode.

            Its default width is 8n.

       [1m.Ud  [22mformats boilerplate text.

                  [1m.Ud  [22m→ currently under development.

            It is neither callable nor parsed and takes no arguments.  Its de‐
            fault width is 8n.

[1mPredefined strings[0m
       The following strings are predefined for compatibility with legacy [4mmdoc[0m
       documents.   Contemporary ones should use the alternatives shown in the
       “Prefer” column below.  See [4mgroff_char[24m(7)  for  a  full  discussion  of
       these special character escape sequences.

       [1mString   7‐bit     8‐bit     UCS   Prefer   Meaning[0m
       \*(<=    <=        <=        ≤     \(<=     less than or equal to
       \*(>=    >=        >=        ≥     \(>=     greater than or equal to
       \*(Rq    "         "         ”     \(rq     right double quote
       \*(Lq    "         "         “     \(lq     left double quote
       \*(ua    ^         ^         ↑     \(ua     vertical arrow up
       \*(aa    '         ´         ´     \(aa     acute accent
       \*(ga    `         `         `     \(ga     grave accent
       \*(q     "         "         "     \(dq     neutral double quote
       \*(Pi    pi        pi        π     \(*p     lowercase pi
       \*(Ne    !=        !=        ≠     \(!=     not equals
       \*(Le    <=        <=        ≤     \(<=     less than or equal to
       \*(Ge    >=        >=        ≥     \(>=     greater than or equal to
       \*(Lt    <         <         <     <        less than
       \*(Gt    >         >         >     >        greater than
       \*(Pm    +-        ±         ±     \(+-     plus or minus
       \*(If    infinity  infinity  ∞     \(if     infinity
       \*(Am    &         &         &     &        ampersand
       \*(Na    [4mNaN[24m       [4mNaN[24m       [4mNaN[24m   NaN      not a number
       \*(Ba    |         |         |     |        bar

       Some  column  headings  are shorthand for standardized character encod‐
       ings; “7‐bit” for ISO 646:1991 IRV (US‐ASCII), “8‐bit” for  ISO  8859‐1
       (Latin‐1)  and  IBM  code  page  1047, and “UCS” for ISO 10646 (Unicode
       character set).  Historically, [4mmdoc[24m configured the  string  definitions
       to fit the capabilities expected of the output device.  Old typesetters
       lacked directional double quotes, producing repeated directional single
       quotes  ‘‘like  this’’; early versions of [4mmdoc[24m in fact defined the ‘Lq’
       and ‘Rq’ strings this way.  Nowadays, output drivers take  on  the  re‐
       sponsibility  of glyph substitution, as they possess relevant knowledge
       of their available repertoires.

[1mDiagnostics[0m
       The debugging macro ‘.Db’ offered by previous versions of [4mmdoc[24m  is  un‐
       available  in  GNU [4mtroff[24m(1) since the latter provides better facilities
       to check parameters; additionally, [4mgroff[24m [4mmdoc[24m implements many error and
       warning messages, making the package more robust and more verbose.

       The remaining debugging macro  is  ‘.Rd’,  which  dumps  the  package’s
       global  register  and  string contents to the standard error stream.  A
       normal user will never need it.

[1mOptions[0m
       The following [4mgroff[24m options set registers (with [1m-r[22m) and  strings  (with
       [1m-d[22m) recognized and used by the [4mmdoc[24m macro package.  To ensure rendering
       consistent  with output device capabilities and reader preferences, man
       pages should never manipulate them.

       Setting string ‘AD’ configures the adjustment mode for  most  formatted
       text.   Typical  values are ‘b’ for adjustment to both margins (the de‐
       fault), or ‘l’ for left alignment (ragged right margin).  Any valid ar‐
       gument to [4mgroff[24m’s ‘ad’ request may be used.  See [4mgroff[24m(7) for less‐com‐
       mon choices.
             [1mgroff -Tutf8 -dAD=l -mdoc groff_mdoc.7 [22m| [1mless -R[0m

       Setting register ‘C’ to 1 numbers output  pages  consecutively,  rather
       than resetting the page number to 1 (or the value of register ‘P’) with
       each new [4mmdoc[24m document.

       By  default,  the package inhibits page breaks, headers, and footers in
       the midst of the document text if it is being displayed with a terminal
       device such as ‘latin1’ or ‘utf8’, to enable more efficient viewing  of
       the  page.   This  behavior can be changed to format the page as if for
       66‐line Teletype output by setting the  continuous  rendering  register
       ‘cR’ to zero while calling [4mgroff[24m(1).
             [1mgroff -Tlatin1 -rcR=0 -mdoc foo.man > foo.txt[0m
       On HTML devices, it cannot be disabled.

       Section  headings  (defined with ‘.Sh’) and page titles in headers (de‐
       fined with ‘.Dt’) can be presented in full capitals by setting the reg‐
       isters ‘CS’ and ‘CT’, respectively, to 1.   These  transformations  are
       off by default because they discard case distinction information.

       Setting  register  ‘D’  to 1 enables double‐sided page layout, which is
       only distinct when not continuously rendering.  It places the page num‐
       ber at the bottom right on odd‐numbered (recto) pages, and at the  bot‐
       tom left on even‐numbered (verso) pages, swapping places with the argu‐
       ments to ‘.Os’.
             [1mgroff -Tps -rD1 -mdoc foo.man > foo.ps[0m

       The  value  of  the ‘FT’ register determines the footer’s distance from
       the page bottom; this amount is always negative and  should  specify  a
       scaling  unit.   At one half‐inch above this location, the page text is
       broken before writing the footer.  It is ignored if continuous  render‐
       ing is enabled.  The default is -0.5i.

       The ‘HF’ string sets the font used for section and subsection headings;
       the default is ‘B’ (bold style of the default family).  Any valid argu‐
       ment to [4mgroff[24m’s ‘ft’ request may be used.

       Normally,  automatic hyphenation is enabled using a mode appropriate to
       the [4mgroff[24m locale; see section “Localization“ of [4mgroff[24m(7).   It  can  be
       disabled by setting the ‘HY’ register to zero.
             [1mgroff -Tutf8 -rHY=0 -mdoc foo.man [22m| [1mless -R[0m

       The paragraph and subsection heading indentation amounts can be changed
       by setting the registers ‘IN’ and ‘SN’.
             [1mgroff -Tutf8 -rIN=5n -rSN=2n -mdoc foo.man [22m| [1mless -R[0m
       The default paragraph indentation is 7.2n on typesetters and 7n on ter‐
       minals.   The default subsection heading indentation amount is 3n; sec‐
       tion headings are set with an indentation of zero.

       The line and title lengths can be changed by setting the registers ‘LL’
       and ‘LT’, respectively:
             [1mgroff -Tutf8 -rLL=100n -rLT=100n -mdoc foo.man [22m| [1mless -R[0m
       If not set, both registers default to 78n for terminal devices and 6.5i
       otherwise.

       Setting the ‘P’ register starts enumeration of pages at its value.  The
       default is 1.

       To change the document font size to 11p or 12p, set  register  ‘S’  ac‐
       cordingly:
             [1mgroff -Tdvi -rS11 -mdoc foo.man > foo.dvi[0m
       Register ‘S’ is ignored when formatting for terminal devices.

       Setting  the  ‘X’ register to a page number [4mp[24m numbers its successors as
       [4mp[24m[1ma[22m, [4mp[24m[1mb[22m, [4mp[24m[1mc[22m, and so forth.  The register tracking the suffixed page let‐
       ter uses format ‘a’ (see the ‘af’ request in [4mgroff[24m(7)).

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/andoc.tmac[0m
               This brief [4mgroff[24m program detects whether the [4mman[24m or [4mmdoc[24m  macro
               package is being used by a document and loads the correct macro
               definitions, taking advantage of the fact that pages using them
               must  call  [1mTH [22mor [1mDd[22m, respectively, before any other macros.  A
               user typing, for example,
                     [1mgroff -mandoc page.1[0m
               need not know which package the file [4mpage.1[24m uses.  Multiple man
               pages, in either format, can  be  handled;  [4mandoc.tmac[24m  reloads
               each macro package as necessary.

       [4m/usr/share/groff/1.23.0/tmac/doc.tmac[0m
               implements the bulk of the [4mgroff[24m [4mmdoc[24m package and loads further
               components as needed from the [4mmdoc[24m subdirectory.

       [4m/usr/share/groff/1.23.0/tmac/mdoc.tmac[0m
               is a wrapper that loads [4mdoc.tmac[24m.

       [4m/usr/share/groff/1.23.0/tmac/mdoc/doc-common[0m
               defines  macros, registers, and strings concerned with the pro‐
               duction of formatted output.  It includes strings of  the  form
               ‘doc-volume-ds-[4mX[24m’  and ‘doc-volume-as-[4mX[24m’ for manual section ti‐
               tles and architecture identifiers, respectively, where [4mX[24m is  an
               argument recognized by .[1mDt[22m.

       [4m/usr/share/groff/1.23.0/tmac/mdoc/doc-nroff[0m
               defines  parameters  appropriate  for rendering to terminal de‐
               vices.

       [4m/usr/share/groff/1.23.0/tmac/mdoc/doc-ditroff[0m
               defines parameters appropriate for rendering to typesetter  de‐
               vices.

       [4m/usr/share/groff/1.23.0/tmac/mdoc/doc-syms[0m
               defines  many  strings  and  macros  that interpolate formatted
               text, such as names of  operating  system  releases,  *BSD  li‐
               braries,  and standards documents.  The string names are of the
               form  ‘doc-str-[4mO[24m[1m-[4m[22mV[24m’,  ‘doc-str-St[1m--[4m[22mS[24m[1m-[4m[22mI[24m’  (observe  the   double
               dashes),  or  ‘doc-str-Lb-[4mL[24m’,  where  [4mO[24m is one of the operating
               system macros from section “General text domain” above, [4mV[24m is an
               encoding of an  operating  system  release  (sometimes  omitted
               along  with  the ‘-’ preceding it), [4mS[24m an identifier for a stan‐
               dards body or committee, [4mI[24m one for an issue of a standard  pro‐
               mulgated by [4mS[24m, and [4mL[24m a keyword identifying a *BSD library.

       [4m/usr/share/groff/site-tmac/mdoc.local[0m
               This  file  houses  local  additions  and customizations to the
               package.  It can be empty.

[1mSee also[0m
       The [4mmandoc[24m: https://mandoc.bsd.lv/ project maintains an independent im‐
       plementation of the [4mmdoc[24m language and a renderer that  directly  parses
       its markup as well as that of [4mman[24m.

       [4mgroff[24m(1), [4mman[24m(1), [4mtroff[24m(1), [4mgroff_man[24m(7), [4mmdoc[24m(7)

[1mBugs[0m
       Section 3f has not been added to the header routines.

       ‘.Fn’  needs  to  have  a check to prevent splitting up the line if its
       length is too short.  Occasionally it separates the  last  parenthesis,
       and sometimes looks ridiculous if output lines are being filled.

       The list and display macros do not do any keeps and certainly should be
       able to.

       As  of [4mgroff[24m 1.23, ‘Tn’ no longer changes the type size; this function‐
       ality may return in the next release.

groff 1.23.0                      5 July 2023                    [4mgroff_mdoc[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_me[24m(7)            Miscellaneous Information Manual            [4mgroff_me[24m(7)

[1mName[0m
       groff_me - “me” macro package for formatting [4mroff[24m documents

[1mSynopsis[0m
       [1mgroff -me [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff -m me [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       The GNU implementation of the [4mme[24m macro package is  part  of  the  [4mgroff[0m
       document  formatting  system.   The [4mme[24m package of macro definitions for
       the [4mroff[24m language provides a convenient facility for preparing  techni‐
       cal  papers  in  various formats.  This version is based on the [4mme[24m dis‐
       tributed with 4.4BSD and can be used with the GNU  [4mtroff[24m  formatter  as
       well as those descended from AT&T [4mtroff[24m.

       Some  formatter  requests affect page layout unpredictably when used in
       conjunction with this package; however, the following may be used  with
       impunity  after  the  first call to a paragraphing macro like [1mlp [22mor [1mpp[22m.
       Some arguments are optional; see [4mgroff[24m(7) for details, particularly  of
       requests whose argument list is designated with an ellipsis.  An aster‐
       isk [1m* [22mmarks [4mgroff[24m extensions.

       [1mad [4m[22mc[24m       set text adjustment mode to [4mc[0m
       [1maf [4m[22mr[24m [4mf[24m     assign format [4mf[24m to register [4mr[0m
       [1mam [4m[22mm[24m [4me[24m     append to macro [4mm[24m until [4me[24m called
       [1mas [4m[22ms[24m [4mt[24m     append rest of line [4mt[24m to string [4ms[0m
       [1mbp [4m[22mn[24m       begin new page numbered [4mn[0m
       [1mbr         [22mbreak output line
       [1mce [4m[22mn[24m       center next [4mn[24m output lines
       [1mcp [4m[22mn[24m       en‐/disable AT&T [4mtroff[24m compatibility mode[1m*[0m
       [1mde [4m[22mm[24m [4me[24m     define macro [4mm[24m until [4me[24m called
       [1mdo [4m[22mt[24m       interpret input [4mt[24m with compatibility mode off[1m*[0m
       [1mds [4m[22ms[24m [4mt[24m     define rest of line [4mt[24m as string [4ms[0m
       [1mel [4m[22mt[24m       interpret [4mt[24m if corresponding [1mie [22mfalse
       [1mfc [4m[22mc[24m [4md[24m     set field delimiter [4mc[24m and padding glyph [4md[0m
       [1mfi         [22menable filling
       [1mhc [4m[22mc[24m       set hyphenation character to [4mc[0m
       [1mhy [4m[22mm[24m       set automatic hyphenation mode to [4mm[0m
       [1mie [4m[22mp[24m [4mt[24m     as [1mif[22m, but enable interpretation of later [1mel[0m
       [1mif [4m[22mp[24m [4mt[24m     if condition [4mp[24m, interpret rest of line [4mt[0m
       [1min [4m[22mh[24m       set indentation to distance [4mh[0m
       [1mlc [4m[22mc[24m       set leader repetition glyph to [4mc[0m
       [1mls [4m[22mn[24m       set line spacing to [4mn[0m
       [1mmc [4m[22mc[24m [4mh[24m     set (right) margin glyph to [4mc[24m at distance [4mh[0m
       [1mmk [4m[22mr[24m       mark vertical position in register [4mr[0m
       [1mna         [22mdisable adjustment of text
       [1mne [4m[22mv[24m       need vertical space of distance [4mv[0m
       [1mnf         [22mdisable filling
       [1mnh         [22mdisable automatic hyphenation
       [1mnr [4m[22mr[24m [4mn[24m [4mi[24m   assign register [4mr[24m value [4mn[24m with auto‐increment [4mi[0m
       [1mns         [22mbegin no‐space mode
       [1mpl [4m[22mv[24m       set page length to [4mv[0m
       [1mpn [4m[22mn[24m       set next page number to [4mn[0m
       [1mpo [4m[22mh[24m       set page offset to [4mh[0m
       [1mrj [4m[22mn[24m       right‐align next [4mn[24m output lines[1m*[0m
       [1mrm [4m[22mm[24m       remove macro, string, or request [4mm[0m
       [1mrn [4m[22mm[24m [4mn[24m     rename macro, string, or request [4mm[24m to [4mn[0m
       [1mrr [4m[22mr[24m       remove register [4mr[0m
       [1mrs         [22mresume spacing (end no‐space mode)
       [1mrt [4m[22mv[24m       return to vertical position set by [1mmk[22m, or [4mv[0m
       [1mso [4m[22mf[24m       source (interpolate) input file [4mf[0m
       [1msp [4m[22mn[24m       insert [4mn[24m lines of vertical space
       [1mta [22m...     set tab stops
       [1mtc [4m[22mc[24m       set tab repetition glyph to [4mc[0m
       [1mti [4m[22mh[24m       set temporary indentation (next line only) to [4mh[0m
       [1mtl [22m...     output three‐part title
       [1mtr [22m...     translate characters
       [1mul [4m[22mn[24m       underline next [4mn[24m output lines

       Except  on title pages (produced by calling [1mtp[22m), [4mme[24m suppresses the out‐
       put of vertical space at the tops of pages (after  the  output  of  any
       page header); the [1msp [22mrequest will thus not work there.  You can instead
       call  [1mbl [22mor enclose the desired spacing request in a diversion, for in‐
       stance by calling [1m(b [22mand [1m)b[22m.  [4mme[24m also intercepts the  [1mll  [22mrequest;  see
       the “[4mme[24m Reference Manual” for details.

   [1mName space[0m
       Objects in [4mme[24m follow a rigid naming convention.  To avoid conflict, any
       user‐defined register, string, or macro names should be single numerals
       or  uppercase  letters,  or any longer sequence of letters and numerals
       with at least one uppercase letter.  (For portability between  BSD  and
       [4mgroff[24m  [4mme[24m,  limit  names  to two characters, and avoid the name [1m[ [22m(left
       square bracket).)  The names  employed  by  any  preprocessors  in  use
       should also not be repurposed.

   [1mMacros[0m
       [1m$0   [22mpost‐section heading hook
       [1m$1   [22mpre‐section depth 1 hook
       [1m$2   [22mpre‐section depth 2 hook
       [1m$3   [22mpre‐section depth 3 hook
       [1m$4   [22mpre‐section depth 4 hook
       [1m$5   [22mpre‐section depth 5 hook
       [1m$6   [22mpre‐section depth 6 hook
       [1m$C   [22mpost‐chapter title hook
       [1m$H   [22mpage/column heading hook
       [1m$c   [22moutput chapter number and title
       [1m$f   [22moutput footer
       [1m$h   [22moutput header
       [1m$p   [22moutput section heading
       [1m$s   [22moutput footnote area separator
       [1m(b   [22mbegin block
       [1m(c   [22mbegin centered block
       [1m(d   [22mbegin delayed text
       [1m(f   [22mbegin footnote
       [1m(l   [22mbegin list
       [1m(q   [22mbegin long quotation
       [1m(x   [22mbegin index entry
       [1m(z   [22mbegin floating keep
       [1m)b   [22mend block
       [1m)c   [22mend centered block
       [1m)d   [22mend delayed text
       [1m)f   [22mend footnote
       [1m)l   [22mend list
       [1m)q   [22mend long quotation
       [1m)x   [22mend index entry
       [1m)z   [22mend floating keep
       [1m++   [22mset document segment type
       [1m+c   [22mbegin chapter
       [1m1c   [22mend multi‐column layout
       [1m2c   [22mbegin multi‐column layout
       [1mEN   [22mend [4meqn[24m equation
       [1mEQ   [22mbegin [4meqn[24m equation
       [1mGE   [22mend [4mgrn[24m picture with drawing position at bottom
       [1mGF   [22mend [4mgrn[24m picture with drawing position at top
       [1mGS   [22mstart [4mgrn[24m picture
       [1mIE   [22mend [4mideal[24m picture with drawing position at bottom
       [1mIF   [22mend [4mideal[24m picture with drawing position at top
       [1mIS   [22mstart [4mideal[24m picture
       [1mPE   [22mend [4mpic[24m picture with drawing position at bottom
       [1mPF   [22mend [4mpic[24m picture with drawing position at top
       [1mPS   [22mstart [4mpic[24m picture
       [1mTE   [22mend [4mtbl[24m table
       [1mTH   [22mend heading for multi‐page [4mtbl[24m table
       [1mTS   [22mstart [4mtbl[24m table
       [1mb    [22membolden argument
       [1mba   [22mset base indentation
       [1mbc   [22mbegin new column
       [1mbi   [22membolden and italicize argument
       [1mbx   [22mbox argument
       [1mef   [22mset even‐numbered page footer
       [1meh   [22mset even‐numbered page header
       [1mep   [22mend page
       [1mfo   [22mset footer
       [1mhe   [22mset header
       [1mhl   [22mdraw horizontal line
       [1mhx   [22msuppress next page’s headers/footers
       [1mi    [22mitalicize argument
       [1mip   [22mbegin indented paragraph
       [1mld   [22mreset localization and date registers and strings[1m*[0m
       [1mll   [22mset line length
       [1mlp   [22mbegin fully left‐aligned paragraph
       [1mnp   [22mbegin numbered paragraph
       [1mof   [22mset odd‐numbered page footer
       [1moh   [22mset odd‐numbered page header
       [1mpd   [22moutput delayed text
       [1mpp   [22mbegin first‐line indented paragraph
       [1mq    [22mquote argument
       [1mr    [22mset argument in roman
       [1mre   [22mreset tab stops
       [1msh   [22mbegin numbered section
       [1msm   [22mset argument at smaller type size
       [1msx   [22mchange section depth
       [1msz   [22mset type size and vertical spacing
       [1mtp   [22mbegin title page
       [1mu    [22munderline argument
       [1muh   [22mbegin unnumbered section
       [1mxl   [22mset line length (local)
       [1mxp   [22moutput index

       Some macros are provided for “old” [4mroff[24m(1) compatibility.  The “[4mme[24m Ref‐
       erence Manual” describes alternatives for modern documents.

       [1mar   [22muse Arabic numerals for page numbers
       [1mbl   [22minsert space (even at page top; cf. [1msp[22m)
       [1mix   [22mset indentation without break
       [1mm1   [22mset page top to header distance
       [1mm2   [22mset header to text distance
       [1mm3   [22mset text to footer distance
       [1mm4   [22mset footer to page bottom distance
       [1mn1   [22mbegin output line numbering
       [1mn2   [22mend or alter output line numbering
       [1mpa   [22mbegin page
       [1mro   [22muse Roman numerals for page numbers
       [1msk   [22mskip next page

   [1mRegisters[0m
       [1m$0   [22msection depth
       [1m$1   [22mfirst section number component
       [1m$2   [22msecond section number component
       [1m$3   [22mthird section number component
       [1m$4   [22mfourth section number component
       [1m$5   [22mfifth section number component
       [1m$6   [22msixth section number component
       [1m$c   [22mcurrent column number
       [1m$d   [22mdelayed text number
       [1m$f   [22mfootnote number
       [1m$i   [22mparagraph base indentation
       [1m$l   [22mcolumn width
       [1m$m   [22mnumber of available columns
       [1m$p   [22mnumbered paragraph number
       [1m$s   [22mcolumn spacing (indentation)
       [1mbi   [22mdisplay (block) indentation
       [1mbm   [22mdistance from text area to page bottom
       [1mbs   [22mdisplay (block) pre/post space
       [1mbt   [22mblock threshold for keeps
       [1mch   [22mcurrent chapter number
       [1mdf   [22mdisplay font
       [1mdv   [22mvertical spacing of displayed text (as percentage)[1m*[0m
       [1mes   [22mequation pre/post space
       [1mff   [22mfootnote font
       [1mfi   [22mfootnote indentation (first line only)
       [1mfm   [22mfooter margin
       [1mfp   [22mfootnote type size in points
       [1mfs   [22mfootnote prespace
       [1mfu   [22mfootnote undent (right indentation)
       [1mhm   [22mheader margin
       [1mii   [22mindented paragraph indentation
       [1mno   [22mline numbering offset[1m*[0m
       [1mpf   [22mparagraph font
       [1mpi   [22mparagraph indentation
       [1mpo   [22mpage offset
       [1mpp   [22mparagraph type size in points
       [1mps   [22mparagraph prespace
       [1mqi   [22mlong quotation left/right indentation
       [1mqp   [22mlong quotation type size in points
       [1mqs   [22mlong quotation pre/post space
       [1msf   [22msection title font
       [1msi   [22msection indentation per level of depth
       [1mso   [22madditional section title offset
       [1msp   [22msection title type size in points
       [1mss   [22msection prespace
       [1msx   [22msuper/subscript line height increase[1m*[0m
       [1mtf   [22mtitle font
       [1mtm   [22mdistance from page top to text area
       [1mtp   [22mtitle type size in points
       [1mtv   [22mvertical spacing of text (as percentage)[1m*[0m
       [1mxs   [22mindex entry prespace
       [1mxu   [22mindex undent (right indentation)
       [1my2   [22myear of the century[1m*[0m
       [1my4   [22myear[1m*[0m
       [1myr   [22myear minus 1900
       [1mzs   [22mfloating keep pre/post space

   [1mStrings[0m
       [1m#    [22mdelayed text marker
       [1m$n   [22mconcatenated section number
       [1m*    [22mfootnote marker
       [1m-    [22mem dash
       [1m<    [22mbegin subscripting
       [1m>    [22mend subscripting
       [1mdw   [22mweekday name
       [1mlq   [22mleft double quotation mark
       [1mmo   [22mmonth name
       [1mrq   [22mright double quotation mark
       [1mtd   [22mdate
       [1mwa   [22mterm for “appendix” used by [1m.$c*[0m
       [1mwc   [22mterm for “chapter” used by [1m.$c*[0m
       [1m{    [22mbegin superscripting
       [1m}    [22mend superscripting

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/e.tmac[0m
              implements the package.

       [4m/usr/share/groff/1.23.0/tmac/refer-me.tmac[0m
              implements [4mrefer[24m(1) support for [4mme[24m.

       [4m/usr/share/groff/1.23.0/tmac/me.tmac[0m
              is  a  wrapper  enabling the package to be loaded with “[1mgroff -m[0m
              [1mme[22m”.

[1mNotes[0m
       Early [4mroff[24m macro packages often limited their names to a single letter,
       which followed the formatter’s [1mm [22mflag letter, resulting in [4mmm[24m, [4mms[24m,  [4mmv[24m,
       [4mmn[24m,  and so on.  The “e” in “me” stands for “Eric P. Allman”, who wrote
       the macro package and the  original  technical  papers  documenting  it
       while an undergraduate at the University of California.

[1mSee also[0m
       Two manuals are available in source and rendered form.  On your system,
       they may be compressed and/or available in additional formats.

       [4m/usr/share/doc/groff-1.23.0/meintro.me[0m
       [4m/usr/share/doc/groff-1.23.0/meintro.ps[0m
              is  “Writing  Papers  with  [4mGroff[24m Using -[4mme[24m”, by Eric P. Allman,
              adapted for [4mgroff[24m by James Clark.

       [4m/usr/share/doc/groff-1.23.0/meref.me[0m
       [4m/usr/share/doc/groff-1.23.0/meref.ps[0m
              is the “[4mme[24m Reference Manual”, by Eric  P.  Allman,  adapted  for
              [4mgroff[24m by James Clark and G. Branden Robinson.

       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       For   preprocessors  supported  by  [4mme[24m,  see  [4meqn[24m(1),  [4mgrn[24m(1),  [4mpic[24m(1),
       [4mrefer[24m(1), and [4mtbl[24m(1).

       [4mgroff[24m(1), [4mtroff[24m(1), [4mgroff[24m(7)

groff 1.23.0                      5 July 2023                      [4mgroff_me[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_mm[24m(7)            Miscellaneous Information Manual            [4mgroff_mm[24m(7)

[1mName[0m
       groff_mm - memorandum macros for GNU [4mroff[0m

[1mSynopsis[0m
       [1mgroff -mm [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff -m mm [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       The GNU implementation of the [4mmm[24m macro package is  part  of  the  [4mgroff[0m
       document  formatting system.  The [4mmm[24m package is suitable for the compo‐
       sition of letters, memoranda, reports, and books.

       Call an [4mmm[24m macro at the beginning of a document to initialize the pack‐
       age.  A simple [4mmm[24m document might use only [1mP [22mfor paragraphing.  Set num‐
       bered and unnumbered section headings  with  [1mH  [22mand  [1mHU[22m,  respectively.
       Change  the  style  of the typeface with [1mB[22m, [1mI[22m, and [1mR[22m; you can alternate
       styles with [1mBI[22m, [1mBR[22m, [1mIB[22m, [1mIR[22m, [1mRB[22m, and [1mRI[22m.  Several  nestable  list  types
       are available via [1mAL[22m, [1mBL[22m, [1mBVL[22m, [1mDL[22m, [1mML[22m, [1mRL[22m, and [1mVL[22m; each of these begins
       a  list,  to which [1mLI [22madds an item and [1mLE [22mends the (nested) list.  Cus‐
       tomized list arrangements are supported by [1mLB[22m.  [1mDS [22mand [1mDF [22mstart  static
       and floating displays, respectively; either is terminated with [1mDE[22m.

       [4mgroff[24m  [4mmm[24m is intended to be compatible with the [4mmm[24m implementation found
       in the AT&T Documenter’s Workbench (DWB), with  the  following  limita‐
       tions.

       • Omitted  features  include  the logo and company name strings, [1m}Z [22mand
         [1m]S[22m, respectively; the encoded company site location addresses  recog‐
         nized  as the third argument to the [1mAU [22mmacro; the [1mPv [22m(“private” head‐
         ing) register; and the [1mOK [22m(other keywords), and [1mPM [22m(proprietary mark‐
         ings) macros.

       • The [1mCS [22m(output cover sheet) macro is implemented only for  memorandum
         type 4.

       • The  [4mgrap[24m  preprocessor  is  not  explicitly  supported; no [1mG1 [22mand [1mG2[0m
         macros are defined.

       • The registers [1mA[22m, [1mC[22m, [1mE[22m, [1mT[22m, and [1mU[22m, typically  set  from  the  [4mtroff[24m  or
         [4mnroff[24m command lines with DWB [4mmm[24m, are not recognized.

       • When  setting  the registers [1mL [22mor [1mW [22mfrom the command line, use an ex‐
         plicit scaling unit to avoid surprises.

       • DWB [4mmm[24m’s [1mnP [22mmacro indented the second line of a paragraph to align it
         with the start of the text of the first (after the paragraph number);
         [4mgroff[24m [4mmm[24m’s does not.

       • Cut marks are not supported.

       DWB [4mmm[24m supported only seven levels of heading.  As a compatible  exten‐
       sion,  [4mgroff[24m [4mmm[24m supports fourteen, introducing new registers [1mH8 [22mthrough
       [1mH14[22m, and affecting the interpretation of the [1mHF [22mand [1mHP [22mstrings.

       Macro, register, and string descriptions in this page  frequently  men‐
       tion each other; most cross references are to macros.  Where a register
       or string is referenced, its type is explicitly identified.  [4mmm[24m’s macro
       names  are usually in full capitals; registers and strings tend to have
       mixed‐case names.

   [1mDocument styles[0m
       [4mgroff[24m [4mmm[24m offers three different frameworks for  document  organization.
       [1mCOVER[22m/[1mCOVEND  [22mis a flexible means of preparing any document requiring a
       cover page.  [1mLT[22m/[1mLO [22maids preparation of  typical  Anglophone  correspon‐
       dence  (business  letters, for example).  The [1mMT [22mmemorandum type mecha‐
       nism implements a group of formal styles historically used by AT&T Bell
       Laboratories.  Your document can  select  at  most  one  of  these  ap‐
       proaches; when used, each disables the others.

   [1mLocalization[0m
       [4mgroff[24m  [4mmm[24m is designed to be easily localized.  For languages other than
       English, strings that can appear in output are collected  in  the  file
       [4m/usr/share/groff/1.23.0/tmac/[24mxx[4m.tmac[24m, where [4mxx[24m is an ISO 639 two‐letter
       language  identifier.  Localization packages should be loaded after [4mmm[24m;
       for example, you might format a Swedish [4mmm[24m document  with  the  command
       “[1mgroff -mm -msv[22m”.

       This  package  can also be localized by site or territory; for example,
       [4m/usr/share/groff/1.23.0/tmac/mse.tmac[24m illustrates how to adapt the out‐
       put to a national standard using its ISO 3166 territory code.   Such  a
       package  can define a string that causes a macro file [4m/usr/share/groff/[0m
       [4m1.23.0/tmac/mm/[24mterritory[4m_locale[24m to be loaded at package initialization.
       If this mechanism is not  used,  [4m/usr/share/groff/1.23.0/tmac/mm/locale[0m
       is loaded instead.  No diagnostic is produced if these files do not ex‐
       ist.

   [1mRegisters and strings[0m
       Much  [4mmm[24m behavior can be configured by registers and strings.  A regis‐
       ter is assigned with the [1mnr [22mrequest.

              [1m.nr [4m[22mident[24m [[1m±[22m][4mn[24m [[4mi[24m]

       [4mident[24m is the name of the register, and [4mn[24m is the value to  be  assigned.
       [4mn[24m can be prefixed with a plus or minus sign if incrementation or decre‐
       mentation  (respectively)  of the register’s existing value by [4mn[24m is de‐
       sired.  If assignment of a (possibly) negative [4mn[24m is  required,  further
       prefix it with a zero or enclose it in parentheses.  If [4mi[24m is specified,
       the register is automatically modified by [4mi[24m prior to interpolation if a
       plus or minus sign is included in the escape sequence as follows.

              [1m\n[22m[[1m±[22m][1m[[4m[22mident[24m[1m][0m

       [4mi[24m  can  be negative; it combines algebraically with the sign in the in‐
       terpolation escape sequence.

       Strings are defined with the [1mds [22mrequest.

              [1m.ds [4m[22mident[24m [4mcontents[0m

       [4mcontents[24m consumes everything up to  the  end  of  the  line,  including
       trailing  spaces.  It is a good practice to end [4mcontents[24m with a comment
       escape sequence ([1m\"[22m) so that extraneous spaces do  not  intrude  during
       document maintenance.  To include leading spaces in [4mcontents[24m, prefix it
       with  a  double quote.  Strings are interpolated with the [1m\* [22mescape se‐
       quence.

              [1m\*[[4m[22mident[24m[1m][0m

       Register and string name spaces are distinct, but  strings  and  macros
       share  a  name  space.   Defining  a string with the same name as an [4mmm[0m
       macro is not supported and may cause incorrect rendering, the  emission
       of diagnostic messages, and an error exit status from [4mtroff[24m.

   [1mRegister format[0m
       A register is interpolated using Arabic numerals if no other format has
       been  assigned  to  it.   Assign a format to a register with the [1maf [22mre‐
       quest.

              [1m.af [4m[22mR[24m [4mc[0m

       [4mR[24m is the name of the register, and [4mc[24m is the format.  If [4mc[24m is a sequence
       of Arabic numerals, their quantity defines a zero‐padded minimum  width
       for the interpolated register value.

              [1mForm   Sequence[0m
              1      0, 1, 2, 3, ..., 10, ...
              001    000, 001, 002, 003, ..., 1000, ...
              i      0, i, ii, iii, iv, ...
              I      0, I, II, III, IV, ...
              a      0, a, b, c, ..., z, aa, ab, ...
              A      0, A, B, C, ..., Z, AA, AB, ...

   [1mFonts[0m
       In  [4mgroff[24m [4mmm[24m, the fonts (or rather, font styles) [1mR [22m(roman), [1mI [22m(italic),
       and [1mB [22m(bold) are mounted at font positions [1m1[22m, [1m2[22m, and  [1m3[22m,  respectively.
       Internally, font positions are used for backward compatibility.  From a
       practical  point  of view, it doesn’t make a big difference—a different
       font family can still be selected by invoking [4mgroff[24m’s  [1mfam  [22mrequest  or
       using  its  [1m-f  [22mcommand‐line option.  On the other hand, if you want to
       replace just, for example, font [1mI  [22mwith  Zapf  Chancery  Medium  italic
       (available  on  [4mgroff[24m’s [1mpdf [22mand [1mps [22moutput devices), you have to use the
       [1mfp [22mrequest, replacing the font at position 2 with “[1m.fp 2  ZCMI[22m”).   Be‐
       cause the cover sheet, memorandum type, and [4mrefer[24m(1) integration macros
       explicitly request fonts named [1mB[22m, [1mI[22m, and [1mR[22m, you will also need to remap
       these font names with the [1mftr [22mrequest, for instance with “[1m.ftr I ZCMI[22m”.

[1mMacros[0m
       An  explicitly  empty  argument  may be specified with a pair of double
       quotes; to call a macro [1mXX [22mwith an empty second argument but  non‐empty
       first and third ones, you could input the following.

              .XX foo "" baz

       Macro names longer than two characters are GNU extensions; some shorter
       names  were not part of DWB [4mmm[24m’s published interface but are documented
       aspects of [4mgroff[24m [4mmm.[0m

       [1m)E [4m[22mlevel[24m [4mtext[0m
              Add heading text [4mtext[24m to the table of contents with [4mlevel[24m, which
              is either 0 or in the range 1 to 7.  See also [1mH[22m.   This  undocu‐
              mented  DWB [4mmm[24m macro is exposed by [4mgroff[24m [4mmm[24m to enable customized
              tables of contents.

       [1m1C [22m[[1m1[22m] Format page text in one column.  The page is broken.  A [1m1  [22margu‐
              ment  suppresses  this  break; its use may cause body text and a
              pending footnote to overprint.  See [1m2C[22m, [1mMC[22m, and [1mNCOL[22m.

       [1m2C     [22mBegin two‐column formatting.  This is a special case of [1mMC[22m.  See
              [1m1C [22mand [1mNCOL[22m.

       [1mAE     [22mAbstract end; stop collecting abstract text.  See [1mAS[22m.

       [1mAF [22m[[4mfirm‐name[24m]
              Specify firm associated with the document.  At most one  can  be
              declared;  the  firm name is used by memorandum types and avail‐
              able to cover sheets.  [1mAF [22mterminates a  document  title  started
              with [1mTL[22m, and can be called without an argument for that purpose.
              See [1mMT [22mand [1mCOVER[22m.

       [1mAL [22m[[4mtype[24m [[4mtext‐indent[24m [[1m1[22m]]]
              Begin an auto‐incrementing numbered list.  Item numbers start at
              one.   The [4mtype[24m argument assigns the register format (see above)
              of the list item enumerators.  The default is [1m1[22m.  An  explicitly
              empty  [4mtype[24m  also indicates the default.  A [4mtext‐indent[24m argument
              overrides register [1mLi[22m.  A third argument  suppresses  the  blank
              line  that  normally precedes each list item.  Use [1mLI [22mto declare
              list items, and [1mLE [22mto end the list.

       [1mAPP [22m[[4mid[24m [[4mtitle[24m]]
              Begin an appendix.  If the identifier [4mid[24m is omitted, it  is  in‐
              cremented  (or  initialized, if necessary).  The register format
              used for [4mid[24m is “A”.  The page is broken.  The register  [1mAph  [22mde‐
              termines  whether  an  appendix heading is then formatted.  This
              heading uses the string [1mApp [22mfollowed by [4mid[24m.   Appendices  appear
              in  any table of contents (see [1mTC[22m).  The string [1mApptxt [22mis set to
              [4mtitle[24m if the latter is present, and made empty otherwise.

       [1mAPPSK [4m[22mid[24m [4mn[24m [[4mtitle[24m]
              As [1mAPP[22m, but increment the page number by [4mn[24m.  Use this  macro  to
              “skip  pages”  when diagrams or other materials not formatted by
              [4mtroff[24m are included in appendices.

       [1mAS [22m[[4mplacement[24m [[4mindentation[24m]]
              Abstract start; begin collecting abstract.  Input up to the next
              [1mAE [22mcall is included in the abstract.  [4mplacement[24m  influences  the
              location of the abstract on the cover sheet of a memorandum (see
              [1mMT[22m).   [1mCOVER[22m, by contrast, ignores [4mplacement[24m by default, but can
              be customized to interpret it.

              [4m[1mplacement[24m   Effect[0m
              0           The abstract appears on page 1 and  cover  sheet  if
                          the  document is a “released paper” memorandum (“[1m.MT[0m
                          [1m4[22m”); otherwise, it appears on page 1 without a cover
                          sheet.
              1           The abstract appears only on the cover  sheet  (“[1m.MT[0m
                          [1m4[22m” only).

              An  abstract  does  not  appear at all in external letters (“[1m.MT[0m
              [1m5[22m”).  A [4mplacement[24m of [1m2 [22mwas supported by DWB [4mmm[24m  but  is  not  by
              [4mgroff[24m [4mmm[24m.

              A  second  argument increases the indentation by [4mindentation[24m and
              reduces the line length by twice this amount.  A scaling unit of
              ens is assumed.  The default is 0.

       [1mAST [22m[[4mcaption[24m]
              Set the caption above the abstract to [4mcaption[24m, or  clear  it  if
              there is no argument.  The default is “ABSTRACT”.

       [1mAT [4m[22mtitle[24m ...
              Specify  author’s title(s).  If present, [1mAT [22mmust appear just af‐
              ter the corresponding author’s [1mAU[22m.  Each [4mtitle[24m occupies an  out‐
              put  line  beneath the author’s name in the signature block used
              by [1mLT [22mletters (see [1mSG[22m) and in [1mMT [22mmemoranda.  The [1mms [22mcover  sheet
              style also uses it.

       [1mAU [22m[[4mname[24m [[4minitials[24m [[4mloc[24m [[4mdept[24m [[4mext[24m [[4mroom[24m [[4marg1[24m [[4marg2[24m [[4marg3[24m]]]]]]]]]
              Specify author.  [1mAU [22mterminates a document title started with [1mTL[22m,
              and  can  be  called without arguments for that purpose.  Author
              information is used by cover sheets, [1mMT [22mmemoranda, and [1mSG[22m.  Fur‐
              ther arguments comprise initials,  location,  department,  tele‐
              phone extension, room number or name, and up to three additional
              items.  Repeat [1mAU [22mto identify multiple authors.

              Use [1mWA[22m/[1mWE [22minstead to identify the author for documents employing
              [1mLT[22m.

       [1mAV [22m[[4mname[24m [[1m1[22m]]
              Format approval lines for a handwritten signature and date.  Two
              horizontal rules are drawn, with the specified [4mname[24m and the text
              of the string [1mLetdate [22mbeneath them.  Above these rules, the text
              in  the  string  [1mLetapp [22mis formatted; a second argument replaces
              this text with a blank line.  See [1mLT[22m.

       [1mAVL [22m[[4mname[24m]
              As [1mAV[22m, but the date, date rule, and approval notation [1mLetapp [22mare
              omitted.

       [1mB [22m[[4mbold‐text[24m [[4mprevious‐font‐text[24m]] ...
              Join [4mbold‐text[24m in boldface with [4mprevious‐font‐text[24m in the previ‐
              ous font, without space between the arguments.  If no arguments,
              switch font to bold style.

       [1mB1     [22mBegin boxed, kept display.  The text is indented one  character,
              and  the  right  margin is one character shorter.  This is a GNU
              extension.

       [1mB2     [22mEnd boxed, kept display.  This is a GNU extension.

       [1mBE     [22mEnd bottom block; see [1mBS[22m.

       [1mBI [22m[[4mbold‐text[24m [[4mitalic‐text[24m]] ...
              Join [4mbold‐text[24m in boldface with [4mitalic‐text[24m in italics,  without
              space between the arguments.

       [1mBL [22m[[4mtext‐indent[24m [[1m1[22m]]
              Begin  bulleted  list.   Items  are prefixed with a bullet and a
              space.  A [4mtext‐indent[24m argument overrides register [1mPi[22m.  A  second
              argument  suppresses  blank  lines between items.  Use [1mLI [22mto de‐
              clare list items, and [1mLE [22mto end the list.

       [1mBR [22m[[4mbold‐text[24m [[4mroman‐text[24m]] ...
              Join [4mbold‐text[24m in boldface with [4mroman‐text[24m in roman style, with‐
              out space between the arguments.

       [1mBS     [22mBegin bottom block.  Input is collected until [1mBE [22mis called,  and
              output between the footnote area and footer of each page.

       [1mBVL [22m[[4mtext‐indent[24m [[4mmark‐indent[24m [[1m1[22m]]]
              Begin broken variable‐item (or “tagged”) list.  Each item is ex‐
              pected  to supply its own mark.  The line is always broken after
              the mark; contrast [1mVL[22m.  [4mtext‐indent[24m sets the indentation of  the
              text,  and [4mmark‐indent[24m the distance from the current list inden‐
              tation to the mark.  A third argument suppresses the blank  line
              that  normally  precedes each list item.  Use [1mLI [22mto declare list
              items, and [1mLE [22mto end the list.

       [1mCOVER [22m[[4mstyle[24m]
              Begin a cover page description.  [1mCOVER [22mmust  appear  before  the
              body text (or main matter) of a document.  The argument [4mstyle[24m is
              used to construct the file name [4m/usr/share/groff/1.23.0/tmac/mm/[0m
              style[4m.cov[24m  and  load it with the [1mmso [22mrequest.  The default [4mstyle[0m
              is [1mms[22m; the [4mms.cov[24m file prepares a cover page resembling those of
              the [4mms[24m package.  A [4m.cov[24m file must define a [1mCOVEND [22mmacro, which a
              document must call at the end of  the  cover  description.   Use
              cover  description macros in the following order; only [1mTL [22mand [1mAU[0m
              are required.

              .COVER
              .TL
              .AF
              .AU
              .AT
              .AS
              .AE
              .COVEND

       [1mCOVEND [22mEnd the cover description.

       [1mDE     [22mEnd static or floating display begun with [1mDS [22mor [1mDF[22m.

       [1mDF [22m[[4mformat[24m [[4mfill[24m [[4mright‐indentation[24m]]]
              Begin floating display.  A floating display is saved in a  queue
              and  output  in  the order entered.  Arguments are handled as in
              [1mDS[22m.  Floating displays cannot be nested.  Placement of  floating
              displays is controlled by the registers [1mDe [22mand [1mDf[22m.

       [1mDL [22m[[4mtext‐indent[24m [[1m1[22m]]
              Begin  dashed  list.   Items  are prefixed with an em dash and a
              space.  A [4mtext‐indent[24m argument overrides register [1mPi[22m.  A  second
              argument  suppresses  blank  lines between items.  Use [1mLI [22mto de‐
              clare list items, and [1mLE [22mto end the list.

       [1mDS [22m[[4mformat[24m [[4mfill[24m [[4mright‐indentation[24m]]]
              Begin static display.  Input until [1mDE  [22mis  called  is  collected
              into  a  display.  The display is output on a single page unless
              it is taller than the height of the  page.   [1mDS  [22mcan  be  nested
              (contrast with [1mDF[22m).

              [4m[1mformat[24m   Effect[0m
              [4mnone[24m     Do not indent the display.
              L        Do not indent the display.
              I        Indent text by [1m\n[Si][22m.
              C        Center each line.
              CB       Center the whole display as a block.
              R        Right‐adjust the lines.
              RB       Right‐adjust the whole display as a block.

              The values “L”, “I”, “C”, and “CB” can also be specified as “0”,
              “1”, “2”, and “3”, respectively, for compatibility with DWB [4mmm.[0m

              [4m[1mfill[24m   Effect[0m
              [4mnone[24m   Disable filling.
              N      Disable filling.
              F      Enable filling.

              “N”  and “F” can also be specified as “0” and “1”, respectively,
              for compatibility with DWB [4mmm.[0m

              A third argument reduces the line length by [4mright‐indentation.[0m

              [4mmm[24m normally places blank lines before  and  after  the  display.
              Set register [1mDs [22mto 0 to suppress these.

       [1mEC [22m[[4mtitle[24m [[4moverride[24m [[4mflag[24m [[4mrefname[24m]]]]
              Caption  an  equation.   The caption consists of the string [1mLiec[0m
              followed by an automatically incrementing counter stored in  the
              register [1mEc[22m, punctuation configured by the register [1mOf[22m, then [4mti‐[0m
              [4mtle[24m  (if any).  Use the [1maf [22mrequest to configure [1mEc[22m’s number for‐
              mat.  [4moverride[24m and [4mflag[24m alter the equation  number  as  follows.
              Omitting [4mflag[24m and specifying [1m0 [22min its place are equivalent.

              [4m[1mflag[24m   Effect[0m
              0      Prefix number with [4moverride[24m.
              1      Suffix number with [4moverride[24m.
              2      Replace number with [4moverride[24m.

              Equation  captions are centered irrespective of the alignment of
              any enclosing display.

              [4mrefname[24m stores the equation number using [1mSETR[22m;  it  can  be  re‐
              treived  with  “[1m.GETST  [4m[22mrefname[24m”.  This argument is a GNU exten‐
              sion.

              Captioned equations are listed in a table of contents  (see  [1mTC[22m)
              if the Boolean register [1mLe [22mis true.  Such a list uses the string
              [1mLe [22mas a heading.

       [1mEF [22m[[1m"'[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'"[22m]
              Define  the  even‐page footer, which is formatted just above the
              normal page footer on even‐numbered pages.  See [1mPF[22m.  [1mEF  [22mdefines
              the string [1mEOPef[22m.

       [1mEH [22m[[1m"'[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'"[22m]
              Define  the  even‐page header, which is formatted just below the
              normal page header on even‐numbered pages.  See [1mPH[22m.  [1mEH  [22mdefines
              the string [1mTPeh[22m.

       [1mEN     [22mEnd equation input preprocessed by [4meqn[24m(1); see [1mEQ[22m.

       [1mEOP    [22mIf  defined,  this macro is called in lieu of normal page footer
              layout.  Headers and footers are formatted in a  separate  envi‐
              ronment.  See [1mTP[22m.

              [1mStrings available to EOP[0m
              ─────────────────────────
              [1mEOPf     [22margument to [1mPF[0m
              [1mEOPef    [22margument to [1mEF[0m
              [1mEOPof    [22margument to [1mOF[0m

       [1mEPIC [22m[[1m-L[22m] [4mwidth[24m [4mheight[24m [[4mname[24m]
              Draw  a box with the given [4mwidth[24m and [4mheight[24m.  It also prints the
              text [4mname[24m or a default string if [4mname[24m is not specified.  This is
              used to include external pictures; just give  the  size  of  the
              picture.   [1m-L [22mleft‐aligns the picture; the default is to center.
              See [1mPIC[22m.

       [1mEQ [22m[[4mlabel[24m]
              Start equation input preprocessed by [4meqn[24m(1).  [1mEQ  [22mand  [1mEN  [22mmacro
              calls  bracket  an  equation  region.  Such regions must be con‐
              tained in displays ([1mDS[22m/[1mDE[22m), except when the region is used  only
              to  configure  [4meqn[24m and not to produce output.  If present, [4mlabel[0m
              appears aligned to the right and centered vertically within  the
              display;  see register [1mEq[22m.  If multiple [4meqn[24m regions occur within
              a display, only the last [4mlabel[24m (if any) is used.

       [1mEX [22m[[4mtitle[24m [[4moverride[24m [[4mflag[24m [[4mrefname[24m]]]]
              Caption an exhibit.  Arguments are handled  analogously  to  [1mEC[22m.
              The  register  [1mEx  [22mis the exhibit counter.  The string [1mLiex [22mpre‐
              cedes the exhibit number and any [4mtitle.[24m   Exhibit  captions  are
              centered irrespective of the alignment of any enclosing display.

              Captioned exhibits are listed in a table of contents (see [1mTC[22m) if
              the Boolean register [1mLx [22mis true.  Such a list uses the string [1mLx[0m
              as a heading.

       [1mFC [22m[[4mclosing‐text[24m]
              Output  the  string [1mLetfc[22m, or the specified [4mclosing‐text,[24m as the
              formal closing of a letter.

       [1mFD [22m[[4marg[24m [[1m1[22m]]
              Configure display of footnotes.  The first argument encodes  en‐
              ablement  of automatic hyphenation, adjustment to the right mar‐
              gin, indentation of footnote text, and left‐ vs. right‐alignment
              of the footnote label within the space allocated for it.

              [4m[1marg[24m   Hyphenate?   Adjust?   Indent?   Label alignment[0m
              0     no           yes       yes       left
              1     yes          yes       yes       left
              2     no           no        yes       left
              3     yes          no        yes       left
              4     no           yes       no        left
              5     yes          yes       no        left
              6     no           no        no        left
              7     yes          no        no        left
              8     no           yes       yes       right
              9     yes          yes       yes       right
              10    no           no        yes       right
              11    yes          no        yes       right

              An [4marg[24m greater than 11 is treated as [1m0[22m.  [4mmm[24m’s default is [1m0[22m.

              If a second argument, conventionally [1m1[22m, is given, footnote  num‐
              bering  is reset when a first‐level heading is encountered.  See
              [1mFS[22m.

       [1mFE     [22mEnd footnote; see [1mFS[22m.

       [1mFG [22m[[4mtitle[24m [[4moverride[24m [[4mflag[24m [[4mrefname[24m]]]]
              Caption a figure.  Arguments are handled analogously to [1mEC[22m.  The
              register [1mFg [22mis the figure counter.  The string [1mLifg [22mprecedes the
              figure number and any [4mtitle.[24m  Figure captions are centered irre‐
              spective of the alignment of any enclosing display.

              Captioned figures are listed in a table of contents (see [1mTC[22m)  if
              the Boolean register [1mLf [22mis true.  Such a list uses the string [1mLf[0m
              as a heading.

       [1mFS [22m[[4mlabel[24m]
              Start  footnote.   Input  until [1mFE [22mis called is collected into a
              footnote.  By  default,  footnotes  are  automatically  numbered
              starting  at 1; the number is available in register [1m:p [22mand, with
              a trailing period, in string [1mF[22m.  This string precedes the  foot‐
              note  text  at  the bottom of the column or page.  Footnotes are
              vertically separated by the product of registers [1mFs [22mand [1mLsp[22m.  In
              [4mgroff[24m [4mmm[24m, footnotes may be used in displays.

              A [4mlabel[24m argument replaces the contents of the string [1mF[22m; it  need
              not  be numeric.  In this event, the footnote marker in the body
              text must be explicitly written.

       [1mGETHN [4m[22mrefname[24m [[4mvarname[24m]
              Include the heading number where the corresponding  “[1m.SETR  [4m[22mref‐[0m
              [4mname[24m” was placed.  This is displayed as “X.X.X.” in pass 1.  See
              [1mINITR[22m.  If [4mvarname[24m is used, [1mGETHN [22msets the string [4mvarname[24m to the
              heading number.

       [1mGETPN [4m[22mrefname[24m [[4mvarname[24m]
              Include  the page number where the corresponding “[1m.SETR [4m[22mrefname[24m”
              was placed.  This is displayed as “9999” in pass 1.  See  [1mINITR[22m.
              If  [4mvarname[24m  is  used, [1mGETPN [22msets the string [4mvarname[24m to the page
              number.

       [1mGETR [4m[22mrefname[0m
              Combine [1mGETHN [22mand [1mGETPN [22mwith the text “chapter”  and  “,  page”.
              The string [1mQrf [22mcontains the text for the cross reference:

                     .ds Qrf See chapter \\*[Qrfh], page \\*[Qrfp].

              [1mQrf [22mmay be changed to support other languages.  Strings [1mQrfh [22mand
              [1mQrfp  [22mare  set  by [1mGETR [22mand contain the page and heading number,
              respectively.

       [1mGETST [4m[22mrefname[24m [[4mvarname[24m]
              Include the string saved with  the  second  argument  to  [1m.SETR[22m.
              This  is  a  dummy  string in pass 1.  If [4mvarname[24m is used, [1mGETST[0m
              sets it to the saved string.  See [1mINITR[22m.

       [1mH [4m[22mlevel[24m [[4mtitle[24m [[4msuffix[24m]]
              Set a numbered section heading at [4mlevel[24m.  [4mmm[24m  produces  numbered
              [4mheading[24m  [4mmarks[24m  of the form [4ma[24m.[4mb[24m.[4mc[24m..., with up to fourteen levels
              of nesting.  Each level’s number  increases  automatically  with
              each  [1mH  [22mcall and is reset to zero when a more significant [4mlevel[0m
              is specified.  “[1m1[22m” is the most significant or coarsest  division
              of  the  document.  Text after an [1mH [22mcall is formatted as a para‐
              graph; calling [1mP [22mis unnecessary.

              [4mtitle[24m specifies an optional title; it must be  double‐quoted  if
              it  contains  spaces.  [4mmm[24m appends [4msuffix[24m to [4mtitle[24m in the body of
              the document, but omits it from any table of contents (see  [1mTC[22m).
              This  facility  can be used to annotate the heading title with a
              footnote.  [4msuffix[24m should not interpolate the [1mF [22mstring; specify a
              footnote mark explicitly.  See [1mFS[22m.

              Heading behavior is highly configurable.  Several registers  set
              a  [4mthreshold,[24m  where  heading  levels  at or below the threshold
              value are handled in one way, and those above it  another.   For
              example,  a heading level within the threshold of register [1mCl [22mis
              included in the table of contents (see [1mTC[22m).

              [4mHeading[24m [4mlayout.[24m  Register [1mEj [22msets a threshold for page  breaking
              (ejection) prior to a heading.  If not preceded by a page break,
              a  heading level below the threshold in register [1mHps [22mis preceded
              by the amount of vertical space in register  [1mHps1[22m,  and  by  the
              amount  in [1mHps2 [22motherwise.  The [1mHb [22mregister sets a threshold be‐
              low which a break occurs after the heading, and register [1mHs [22msets
              a threshold below which vertical space follows it.  If the head‐
              ing level is not less than both of these, a  [4mrun‐in[24m  [4mheading[24m  is
              produced;  paragraph text follows on the same output line.  Oth‐
              erwise, register [1mHi [22mconfigures the  indentation  of  text  after
              headings.   Threshold register [1mHc [22menables the centering of head‐
              ings; a heading level below both of the [1mHb [22mand [1mHc [22mthresholds  is
              centered.

              [4mHeading[24m  [4mtypeface[24m  [4mand[24m [4msize.[24m  The fonts used for heading numbers
              and titles at each level are configured by the [1mHF  [22mstring.   The
              string  [1mHP  [22mlikewise  assigns a type size to each heading level.
              The vertical spacing used by headings may be controlled  by  the
              user‐definable macros [1mHX [22mand/or [1mHZ[22m.

              [4mHeading[24m  [4mnumber[24m  [4mformat.[24m   Registers  named [1mH1 [22mthrough [1mH14 [22mstore
              counters for each heading level.  Their values are printed using
              Arabic numerals by default; see  [1mHM[22m.   The  heading  levels  are
              catenated with dots for formatting; to typeset only the deepest,
              set  the  [1mHt  [22mregister.  Heading numbers are not suffixed with a
              trailing dot except when only the first level is output; to omit
              a dot in this case as well, clear the [1mH1dot [22mregister.

              [4mCustomizing[24m [4mheading[24m [4mbehavior.[24m  [4mmm[24m calls [4mhook[24m  macros  to  enable
              further  customization  of  headings.  (DWB [4mmm[24m called these “ex‐
              its”.)  They can be used to change the heading’s [4mmark[24m (the  num‐
              bered  portion  before any heading title), its vertical spacing,
              and its vertical space requirements (for instance, to require  a
              minimum  quantity  of  subsequent  output  lines).   Define hook
              macros in expectation of the following parameters.  The argument
              [4mdeclared‐level[24m is the [4mlevel[24m argument to [1mH[22m, or [1m0  [22mfor  unnumbered
              headings  (see  [1mHU[22m).  [4mactual‐level[24m is the same as [4mdeclared‐level[0m
              for numbered headings, and the value of register [1mHu  [22mfor  unnum‐
              bered headings.  [4mtitle[24m is the corresponding argument to [1mH [22mor [1mHU[22m.

              [1mHX [4m[22mdeclared‐level[24m [4mactual‐level[24m [4mtitle[0m
                     [4mmm[24m  calls [1mHX [22mbefore setting the heading.  Your definition
                     may alter [1m}0[22m, [1m}2[22m, and [1m;3[22m.

                     [1m}0 [22m(string)
                            contains the heading mark plus two spaces  if  [4mde‐[0m
                            [4mclared‐level[24m is non‐zero, and otherwise is empty.

                     [1m;0 [22m(register)
                            encodes a position for the text after the heading.
                            0  means that the heading is to be run in, 1 means
                            that a break is to  occur  before  the  text,  and
                            2 means that vertical space is to separate heading
                            and text.

                     [1m}2 [22m(string)
                            is the suffix that separates a run‐in heading from
                            the  text.   It contains two spaces if register [1m;0[0m
                            is 0, and otherwise is empty.

                     [1m;3 [22m(register)
                            contains the vertical space required for the head‐
                            ing to be typeset.  If that amount is  not  avail‐
                            able,  the  page  is  broken prior to the heading.
                            The default is [1m2v[22m.

              [1mHY [4m[22mdeclared‐level[24m [4mactual‐level[24m [4mtitle[0m
                     [4mmm[24m calls [1mHY [22mafter  determing  the  heading  typeface  and
                     size.  It could be used to change indentation.

              [1mHZ [4m[22mdeclared‐level[24m [4mactual‐level[24m [4mtitle[0m
                     [4mmm[24m  calls  [1mHZ [22mafter formatting the heading, just before [1mH[0m
                     or [1mHU [22mreturns.  It could  be  used  to  change  the  page
                     header to include a section heading.

       [1mHC [22m[[4mhyphenation‐character[24m]
              Set  hyphenation  character.   Default value is “\%”.  Resets to
              the default if called  without  argument.   Hyphenation  can  be
              turned  off  by setting register [1mHy [22mto 0 at the beginning of the
              file.

       [1mHM [22m[[4marg1[24m [[4marg2[24m [... [[4marg14[24m]]]]
              Set the heading mark style.  Each argument assigns the specified
              register format (see above) to the corresponding heading  level.
              The  default  is [1m1 [22mfor all levels.  An explicitly empty argument
              also indicates the default.

       [1mHU [4m[22mheading‐text[0m
              Set an unnumbered section heading.  Except for a heading number,
              it is treated as a numbered heading of the level stored in  reg‐
              ister [1mHu[22m; see [1mH[22m.

       [1mI [22m[[4mitalic‐text[24m [[4mprevious‐font‐text[24m]] ...
              Join  [4mitalic‐text[24m in italics with [4mprevious‐font‐text[24m in the pre‐
              vious font, without space between the arguments.   If  no  argu‐
              ments, switch font to italic style.

       [1mIA [22m[[4mrecipient‐name[24m [[4mtitle[24m]]
              Specify the inside address in a letter.  Input is collected into
              the inside address until [1mIE [22mis called, and then output.  You can
              specify  multiple  recipients  with  empty [1mIA[22m/[1mIE [22mpairs; only the
              last address is used.  The arguments give each recipient a  name
              and title.  See [1mLT[22m.

       [1mIB [22m[[4mitalic‐text[24m [[4mbold‐text[24m]] ...
              Join  [4mitalic‐text[24m in italics with [4mbold‐text[24m in boldface, without
              space between the arguments.

       [1mIE     [22mEnd the inside address begun with [1mIA[22m.

       [1mIND [4m[22margument[24m ...
              If the Boolean register [1mRef [22mis true, write an index entry  as  a
              specially  prepared  [4mroff[24m  comment to the standard error stream,
              with each [4margument[24m separated from its predecessor by a tab char‐
              acter.  The entry’s location information is arranged as  config‐
              ured by the most recent [1mINITI [22mcall.

       [1mINDP   [22mOutput the index set up by [1mINITI [22mand populated by [1mIND [22mcalls.  By
              default, [1mINDP [22mcalls [1mSK [22mand writes a centered caption interpolat‐
              ing  the  string  [1mIndex[22m.  It then disables filling and calls [1m2C[22m;
              afterward, it restores filling and calls [1m1C[22m.

              Define macros to customize this behavior.  [1mINDP [22mcalls [1mTXIND  [22mbe‐
              fore  the  caption,  [1mTYIND  [4m[22minstead[24m  of writing the caption, and
              [1mTZIND [22mafter formatting the index.

       [1mINITI [4m[22mlocation‐type[24m [4mfile‐name[24m [[4mmacro[24m]
              Initialize [4mgroff[24m [4mmm[24m’s indexing system.   Argument  [4mlocation‐type[0m
              selects how the location of each index entry is reported.  [4mfile‐[0m
              [4mname[24m populates an internal string used later by [1mINDP[22m.

              [4m[1mlocation‐type[24m   Entry format[0m
              N               page number
              H               heading mark
              B               page number, tab character, heading mark

              If  [4mmacro[24m  is  specified, it is called for each index entry with
              the arguments given to [1mIND[22m.

       [1mINITR [4m[22mid[0m
              Initialize the cross reference  macros.   Cross  references  are
              written to the standard error stream, which should be redirected
              into  a  file  named id[4m.qrf[24m.  [4mmmroff[24m(1) handles this and the two
              formatting passes it requires.  The first pass identifies  cross
              references, and the second one includes them.

              See [1mSETR[22m, [1mGETPN[22m, and [1mGETHN[22m.

       [1mIR [22m[[4mitalic‐text[24m [[4mroman‐text[24m]] ...
              Join  [4mitalic‐text[24m  in  italics  with  [4mroman‐text[24m in roman style,
              without space between the arguments.

       [1mISODATE [22m[[1m0[22m]
              Use ISO 8601 format for the date string [1mDT [22mused  by  some  cover
              sheet and memorandum types; that is, [4mYYYY[24m‐[4mMM[24m‐[4mDD[24m.  Must be called
              before  [1mND [22mto be effective.  If given an argument of [1m0, [22mthe tra‐
              ditional date format for the [4mgroff[24m locale is used; this is  also
              the default.

       [1mLB [4m[22mtext‐indent[24m [4mmark‐indent[24m [4mpad[24m [4mtype[24m [[4mmark[24m [[4mpre‐item‐space[24m [[4mpre‐list‐[0m
       [4mspace[24m]]]
              Begin  list.  The macros [1mAL[22m, [1mBL[22m, [1mBVL[22m, [1mDL[22m, [1mML[22m, [1mRL[22m, and [1mVL [22mcall [1mLB[0m
              in various ways; they are simpler to use and may be preferred if
              they suit the desired purpose.

              The nesting level of lists is tracked by [4mmm;[24m the outermost level
              is 0.  The text of each list item is  indented  by  [4mtext‐indent;[0m
              the default is taken from the [1mLi [22mregister (in ens).  Each item’s
              mark is indented by [4mmark‐indent;[24m the default is [1m0n[22m.  The mark is
              normally left‐aligned.  If [4mpad[24m is greater than zero, [4mmark‐indent[0m
              is  overridden such that [4mpad[24m ens of space follow the mark.  [4mtype[0m
              selects one of six possible ways to display the mark.

              [4m[1mtype[24m   Output for a mark “x”[0m
              1      x.
              2      x)
              3      (x)
              4      [x]
              5      <x>
              6      {x}

              If [4mtype[24m is 0 and [4mmark[24m is unspecified, the items are set  with  a
              hanging  indent.   Otherwise,  [4mmark[24m  is  interpreted as a string
              defining the mark.  If [4mtype[24m is greater than zero, items are  au‐
              tomatically  numbered; [4mmark[24m is interpreted as a register format.
              The default [4mtype[24m is [1m0[22m.

              The last two arguments manage vertical space.  Unless  a  list’s
              nesting  level  is  greater  than  the value of register [1mLs[22m, its
              items are preceded by [4mpre‐item‐space[24m multiplied by the  register
              [1mLsp[22m;  the  default is [1m1[22m.  [1mLB [22mprecedes the list by [4mpre‐list‐space[0m
              multiplied by the register [1mLsp[22m; the default is [1m0[22m.

       [1mLC [22m[[4mlist‐level[24m]
              Clear list state.  Active lists are terminated as  if  with  [1mLE[22m,
              either  all  (the  default) or only those from the current level
              down to [4mlist‐level[24m if specified.  [1mH [22mcalls [1mLC [22mautomatically.

       [1mLE [22m[[1m1[22m] End list.  The current list is terminated.   An  argument  of  [1m1[0m
              causes  vertical  space  in the amount of register [1mLsp [22mto follow
              the list.

       [1mLI [22m[[4mmark[24m [[4mitem‐mark‐mode[24m]]
              Begin a list item.  Input is collected into a  list  item  until
              the  current  list  is terminated or [1mLI [22mis called again.  By de‐
              fault, the item’s text is preceded by any mark configured by the
              current list.  If only [4mmark[24m is specified, it replaces  the  con‐
              figured mark.  A second argument prefixes [4mmark[24m to the configured
              mark;  an  [4mitem‐mark‐mode[24m value of 1 places an unbreakable space
              after [4mmark,[24m while a value of 2 does not (rendering the two adja‐
              cent).  Also see register [1mLimsp[22m.

       [1mLO [4m[22moption[24m [[4mvalue[24m]
              Specify letter options; see [1mLT[22m.  Standard options  are  as  fol‐
              lows.  See [1mIA [22mregarding the inside address and string [1mDT [22mregard‐
              ing the date.

              [4m[1moption[24m   Effect[0m
              AT       Attention; put contents of string [1mLetAT [22mand [4mvalue[24m left‐
                       aligned after the inside address.
              CN       Confidential;  put  [4mvalue,[24m or contents of string [1mLetCN[22m,
                       left‐aligned after the date.
              RN       Reference; put contents of string [1mLetRN [22mand [4mvalue[24m after
                       the confidental notation (if any) and the date, aligned
                       with the latter.
              SA       Salutation; put [4mvalue,[24m or  contents  of  string  [1mLetSA[22m,
                       left‐aligned after the inside address and the confiden‐
                       tal notation (if any).
              SJ       Subject;  put  contents of string [1mLetSJ [22mand [4mvalue[24m left‐
                       aligned after the inside address and the attention  and
                       salutation  notations  (if  any).  In letter type “SP”,
                       [1mLetSJ [22mis ignored and [4mvalue[24m is set in full capitals.

       [1mLT [22m[[4mstyle[24m]
              Format a letter in the designated [4mstyle,[24m defaulting to  [1mBL  [22m(see
              below).  A letter begins with the writer’s address ([1mWA[22m/[1mWE[22m), fol‐
              lowed  by the date ([1mND[22m), the inside address ([1mIA[22m/[1mIE[22m), the body of
              the letter ([1mP [22mand other general‐purpose [4mmm[24m macros),  the  formal
              closing ([1mFC[22m), the signature ([1mSG[22m), and notations ([1mNS[22m/[1mNE[22m).  Any of
              these may be omitted.  Letter options specified with [1mLO [22madd fur‐
              ther  annotations, which are extensible; see section “Internals”
              below.

              [4m[1mstyle[24m   Description[0m
              [1mBL      [22mBlocked: the writer’s address, date, formal closing, and
                      signature are  indented  to  the  center  of  the  line.
                      Everything else is left‐aligned.
              [1mSB      [22mSemi‐blocked:  as  [1mBL[22m,  but the first line of each para‐
                      graph is indented by [1m5m[22m.
              [1mFB      [22mFully blocked: everything begins at the left margin.
              [1mSP      [22mSimplified: as [1mFB[22m, but a formal closing is omitted,  and
                      the signature is set in full capitals.

       [1mMC [4m[22mcolumn‐width[24m [[4mgutter‐width[24m]
              Begin  multi‐column layout.  [4mgroff[24m [4mmm[24m creates as many columns of
              [4mcolumn‐width[24m as the line length will  permit.   [4mgutter‐width[24m  is
              the  interior  spacing  between columns.  It defaults to [4mcolumn‐[0m
              [4mwidth[24m/15.  [1m1C [22mreturns to single‐column layout.  [1mMC [22mis a GNU  ex‐
              tension.  See [1mMULB [22mfor an alternative.

       [1mML [4m[22mmark[24m [[4mtext‐indent[24m [[1m1[22m]]
              Start  a  list  with the [4mmark[24m argument preceding each list item.
              [4mtext‐indent[24m overrides the default indentation of the list  items
              set  by  register [1mLi[22m.  If a third argument, conventionally [1m1[22m, is
              given, the blank line that normally precedes each list  item  is
              suppressed.   Use  [1mLI  [22mto  declare list items, and [1mLE [22mto end the
              list.

       [1mMT [22m[[4mtype[24m [[4maddressee[24m]]
              Select memorandum type.  These correspond  to  formats  used  by
              AT&T  Bell  Laboratories, where the [4mmm[24m package was initially de‐
              veloped, affecting the document layout.  Some of these  included
              a cover page with a caption categorizing the document.  [4mgroff[24m [4mmm[0m
              uses  [4mtype[24m  to  construct the file name [4m/usr/share/groff/1.23.0/[0m
              [4mtmac/mm/[24mtype[4m.MT[24m and load it with the  [1mmso  [22mrequest.   Memorandum
              types 0 to 5 are supported; any other value of [4mtype[24m is mapped to
              type  6.   If  [4mtype[24m  is omitted, [1m0 [22mis implied.  [4maddressee[24m sets a
              string analogous to one used by AT&T cover sheet macros that are
              not implemented in [4mgroff[24m [4mmm[24m.

              [4m[1mtype[24m   Description[0m
              0      normal memorandum; no caption
              1      captioned “MEMORANDUM FOR FILE”
              2      captioned “PROGRAMMER’S NOTES”
              3      captioned “ENGINEER’S NOTES”
              4      released paper
              5      external letter

              See [1mCOVER [22mfor a more flexible cover sheet mechanism.

       [1mMOVE [4m[22my‐pos[24m [[4mx‐pos[24m [[4mline‐length[24m]]
              Move to a position, setting page  offset  to  [4mx‐pos[24m.   If  [4mline‐[0m
              [4mlength[24m is not given, the difference between current and new page
              offset  is used.  Use [1mPGFORM [22mwithout arguments to return to nor‐
              mal.

       [1mMULB [4m[22mcw1[24m [4mspace1[24m [[4mcw2[24m [4mspace2[24m] ... [4mcwn[0m
              Begin alternative multi‐column mode.  All column widths must  be
              specified, as must the amount of space between each column pair.
              The arguments’ default scaling unit is [1mn[22m.  [1mMULB [22muses a diversion
              and operates in a separate environment.

       [1mMULN   [22mBegin next column in alternative column mode.

       [1mMULE   [22mEnd alternative multi‐column mode and emit the columns.

       [1mNCOL   [22mMove to the start of the next column (only when using [1m2C [22mor [1mMC[22m).
              Contrast with [1mMULN[22m.

       [1mND [22m[[4marg[24m]
              Set the document’s date.  [4mmm[24m does not interpret [4marg[24m; it can be a
              revision identifier (or empty).

       [1mNE     [22mEnd notation begun with [1mNS[22m; filling is enabled.

       [1mnP [22m[[4mtype[24m]
              Begin a numbered paragraph at heading level two.  See [1mP[22m.

       [1mNS [22m[[4mcode[24m [[1m1[22m]]
              Declare  notations,  typically  for letters or memoranda, of the
              type specified by [4mcode[24m.  The text corresponding to [4mcode[24m is  out‐
              put,  and  filling is disabled until [1mNE [22mis called.  Typically, a
              list of names or attachments lies within [1mNS[22m/[1mNE[22m.  If [4mcode[24m is  ab‐
              sent  or does not match one of the values listed under the [1mLetns[0m
              string description below, each line of notations is formatted as
              “Copy ([4mline[24m) to”.  If a second argument,  conventionally  [1m1[22m,  is
              given, [4mcode[24m becomes the entire notation and [1mNE [22mis not necessary.
              In  [4mgroff[24m  [4mmm[24m, you can set up further notations to be recognized
              by [1mNS[22m; see the strings [1mLetns [22mand [1mLetnsdef [22mbelow.

       [1mOF [22m[[1m"'[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'"[22m]
              Define the odd‐page footer, which is formatted  just  above  the
              normal  page  footer on odd‐numbered pages.  See [1mPF[22m.  [1mOF [22mdefines
              the string [1mEOPof[22m.

       [1mOH [22m[[1m"'[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'"[22m]
              Define the odd‐page header, which is formatted  just  below  the
              normal  page  header on odd‐numbered pages.  See [1mPH[22m.  [1mOH [22mdefines
              the string [1mTPoh[22m.

       [1mOP     [22mMake sure that the following text is printed at the  top  of  an
              odd‐numbered  page.   Does not output an empty page if currently
              at the top of an odd page.

       [1mP [22m[[4mtype[24m]
              Begin new paragraph.  If [4mtype[24m is missing or  0, [1mP [22msets the para‐
              graph fully left-aligned.  A [4mtype[24m of 1 idents the first line  by
              [1m\[Pi]  [22mens.   Set  the register [1mPt [22mto select a default paragraph
              indentation style.  The register [1mPs [22mcontrols the vertical  spac‐
              ing between paragraphs.

       [1mPE     [22mPicture end; see [4mpic[24m(1).

       [1mPF [22m[[1m"'[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'"[22m]
              Define  the  page footer.  The footer is formatted at the bottom
              of each page; the argument is otherwise as described in [1mPH[22m.   [1mPF[0m
              defines the string [1mEOPf[22m.  See [1mEF[22m, [1mOF[22m, and [1mEOP[22m.

       [1mPGFORM [22m[[4mlinelength[24m [[4mpagelength[24m [[4mpageoffset[24m [[1m1[22m]]]]
              Set  line  length,  page length, and/or page offset.  This macro
              can be used for letterheads and similar.   It  is  normally  the
              first  macro call in a file, though it is not necessary.  [1mPGFORM[0m
              can be used without arguments to reset everything after  a  [1mMOVE[0m
              call.  A line break is done unless the fourth argument is given.
              This  can  be  used  to  avoid the page number on the first page
              while setting new width and length.  (It seems as if this  macro
              sometimes doesn’t work too well.  Use the command‐line arguments
              to change line length, page length, and page offset instead.)

       [1mPGNH   [22mSuppress header on the next page.  This macro must be called be‐
              fore  any macros that produce output to affect the layout of the
              first page.

       [1mPH [22m[[1m"'[4m[22mleft[24m[1m'[4m[22mcenter[24m[1m'[4m[22mright[24m[1m'"[22m]
              Define the page header, formatted at the top of  each  page,  as
              the  argument,  where [4mleft[24m, [4mcenter[24m, and [4mright[24m are aligned to the
              respective locations on the line.  A “[1m%[22m” character in [4marg[24m is re‐
              placed by the page number.  If the argument is absent,  no  page
              header is set.  The default page header is
                     "''- % -''"
              which  centers the page number between hyphens and formats noth‐
              ing at the upper left and right.  Header macros call [1mPX [22m(if  de‐
              fined)  after formatting the header.  [1mPH [22mdefines the string [1mTPh[22m.
              See [1mEH[22m, [1mOH[22m, and [1mTP[22m.

       [1mPIC [22m[[1m-B[22m] [[1m-C[22m|[1m-I [4m[22mn[24m|[1m-L[22m|[1m-R[22m] [4mfile[24m [[4mwidth[24m [[4mheight[24m]]
              Include PostScript document  [4mfile[24m.   The  optional  [1m-B  [22margument
              draws  a  box  around the picture.  The optional [1m-L[22m, [1m-C[22m, [1m-R[22m, and
              [1m-I [4m[22mn[24m arguments align the picture or indent it by [4mn[24m  (assuming  a
              scaling  unit  of  [1mm[22m).  By default, the picture is left‐aligned.
              Optional [4mwidth[24m and [4mheight[24m arguments resize the picture.  Use  of
              this   macro   requires   two‐pass  processing;  see  [1mINITR  [22mand
              [4mmmroff[24m(1).

       [1mPS     [22mPicture start; see [4mpic[24m(1).

       [1mPY     [22mPicture end with flyback.  Ends a [4mpic[24m(1) picture, returning  the
              vertical position to where it was prior to the picture.  This is
              a GNU extension.

       [1mR [22m[[4mroman‐text[24m [[4mprevious‐font‐text[24m]] ...
              Join  [4mroman‐text[24m  in  roman style with [4mprevious‐font‐text[24m in the
              previous font, without space between the arguments.  If no argu‐
              ments, switch font to roman style.

       [1mRB [22m[[4mroman‐text[24m [[4mbold‐text[24m]] ...
              Join [4mroman‐text[24m in roman style with [4mbold‐text[24m in boldface, with‐
              out space between the arguments.

       [1mRD [22m[[4mprompt[24m [[4mdiversion[24m [[4mstring[24m]]]
              Read from standard input to diversion and/or string.   The  text
              is  saved  in  a  diversion named [4mdiversion[24m.  Recall the text by
              writing the name of the diversion after a dot on an empty  line.
              A  string  is also defined if [4mstring[24m is given.  [4mDiversion[24m and/or
              [4mprompt[24m can be empty ("").

       [1mRF     [22mReference end.  Ends a reference definition and returns to  nor‐
              mal processing.  See [1mRS[22m.

       [1mRI [22m[[4mroman‐text[24m [[4mitalic‐text[24m]] ...
              Join  [4mroman‐text[24m  in  roman  style  with [4mitalic‐text[24m in italics,
              without space between the arguments.

       [1mRL [22m[[4mtext‐indent[24m [[1m1[22m]]
              Begin reference list.  Each item is preceded by an automatically
              incremented number between square brackets; compare  [1mAL[22m.   [4mtext‐[0m
              [4mindent[24m  changes the default indentation.  Use [1mLI [22mto declare list
              items, and [1mLE [22mto end the list.  A second  argument,  convention‐
              ally  [1m1[22m,  suppresses  the blank line that normally precedes each
              list item.

       [1mRP [22m[[4msuppress‐counter‐reset[24m [[4mpage‐ejection‐policy[24m]]
              Format a reference page, listing items accumulated within  [1mRS[22m/[1mRF[0m
              pairs.  The reference counter is reset unless the first argument
              is  [1m1[22m.   Normally, page breaks occur before and after the refer‐
              ences are output; the register [1mRpe [22mconfigures this behavior, and
              a second argument overrides its value.  [1mTC  [22mcalls  [1mRP  [22mautomati‐
              cally if references have accumulated.

              References  are  list  items,  and thus are vertically separated
              (see [1mLB[22m).  Setting register [1mLs [22mto  [1m0  [22msuppresses  this  spacing.
              The string [1mRp [22mcontains the reference page caption.

       [1mRS [22m[[4mreference‐string[24m]
              Begin  an  automatically  numbered reference definition.  By de‐
              fault, references are numbered starting  at  1;  the  number  is
              available  in  register [1m:R[22m.  Interpolate the string [1mRf [22mwhere the
              reference mark should be and write the reference  between  [1mRS[22m/[1mRF[0m
              on  an input line after the reference mark.  If [4mreference‐string[0m
              is specified, [4mgroff[24m [4mms[24m also  stores  the  reference  mark  in  a
              string  of that name, which can be interpolated as [1m\*[[4m[22mreference‐[0m
              [4mstring[24m[1m] [22msubsequently.

       [1mS [22m[[4mtype‐size[24m [[4mvertical‐spacing[24m]]
              Set type size and vertical spacing.  Each argument  is  a  [4mgroff[0m
              measurement, using an appropriate scaling unit and an optional [1m+[0m
              or [1m- [22mprefix to increment or decrement the current value.  An ar‐
              gument of [1mP [22mrestores the previous value, [1mC [22mindicates the current
              value, and [1mD [22mrequests the default.  An empty or omitted argument
              is treated as [1mP[22m.

       [1mSA [22m[[4mmode[24m]
              Set  or restore the default enablement of adjustment.  Specify [1m0[0m
              or [1m1 [22mas [4mmode[24m to set a document’s default explicitly;  [1m1  [22mis  as‐
              sumed  by  [4mmm[24m.  Adjustment can be temporarily suspended with the
              [1mna [22mrequest.  When the [1mH [22mor [1mHU [22mmacros are used to format a  head‐
              ing,  or  when [1mSA [22mis called without a [4mmode[24m argument, the default
              adjustment is restored.

       [1mSETR [4m[22mrefname[24m [[4mstring[24m]
              Remember the current heading and page numbers as [4mrefname[24m.  Saves
              [4mstring[24m if [4mstring[24m is defined.  [4mstring[24m is  retrieved  with  [1mGETST[22m.
              See [1mINITR[22m.

       [1mSG [22m[[4marg[24m [[1m1[22m]]
              Signature  line.   Prints  the  authors name(s) after the formal
              closing.  The  argument  is  appended  to  the  reference  data,
              printed  at either the first or last author.  The reference data
              is the location, department, and initials specified with [1mAU[22m.  It
              is printed at the first author if the second argument is  given,
              otherwise  at the last.  No reference data is printed if the au‐
              thor(s) is specified through [1mWA[22m/[1mWE[22m.  See section “Internals” be‐
              low.

       [1mSK [22m[[4mn[24m] Skip [4mn[24m pages.  If [4mn[24m is 0 or omitted, the page is  broken  unless
              the  drawing  position  is already at the top of a page.  Other‐
              wise, [4mn[24m pages, blank except for any  headers  and  footers,  are
              printed.

       [1mSM [4m[22mtext[24m [[4mpost[24m]
       [1mSM [4m[22mpre[24m [4mtext[24m [4mpost[0m
              Format  [4mtext[24m  at  a smaller type size, joined with any specified
              [4mpre[24m and [4mpost[24m at normal size.

       [1mSP [22m[[4mlines[24m]
              Space vertically.  [4mlines[24m can have any scaling factor, like  “3i”
              or  “8v”.   Several [1mSP [22mcalls in a line only produces the maximum
              number of lines, not the sum.  [1mSP  [22mis  ignored  also  until  the
              first  text line in a page.  Add [1m\& [22mbefore a call to [1mSP [22mto avoid
              this.

       [1mTAB    [22mReset tab stops to every 5 ens.

       [1mTB [22m[[4mtitle[24m [[4moverride[24m [[4mflag[24m [[4mrefname[24m]]]]
              Caption a table.  Arguments are handled analogously to [1mEC[22m.   The
              register  [1mTb [22mis the table counter.  The string [1mLitb [22mprecedes the
              table number and any [4mtitle.[24m  Table captions are  centered  irre‐
              spective of the alignment of any enclosing display.

              Captioned  tables  are listed in a table of contents (see [1mTC[22m) if
              the Boolean register [1mLt [22mis true.  Such a list uses the string [1mLt[0m
              as a heading.

       [1mTC [22m[[4mslevel[24m [[4mspacing[24m [[4mtlevel[24m [[4mtab[24m [[4mh1[24m [[4mh2[24m [[4mh3[24m [[4mh4[24m [[4mh5[24m]]]]]]]]]
              Output table of contents.   This  macro  is  normally  the  last
              called in the document.  It flushes any pending displays and, if
              any references are pending (see [1mRS[22m), calls [1mRP[22m.  It then begins a
              new  page with the contents caption, stored in the string [1mLicon[22m,
              centered at the top.  The entries follow  after  three  vees  of
              space.  Each entry is a saved section (number and) heading title
              (see  the  [1mCl  [22mregister), along with its associated page number.
              By default, an entry is indented by an amount  corresponding  to
              its  heading level and the maximum heading length encountered at
              that heading level; if defined, the string  [1mCi  [22moverrides  these
              indentations.   Entries  at  heading  levels up to and including
              [4mslevel[24m are preceded by [4mspacing[24m vees of space.  Entries at  head‐
              ing  levels  up to and including [4mtlevel[24m are followed by a leader
              and a right‐aligned page number.  If the Boolean‐valued [4mtab[24m  ar‐
              gument is true, the leader is replaced with horizontal motion in
              the  same  amount.   For entries above heading level [4mtlevel[24m, the
              page number follows the heading text after a word  space.   Each
              argument  [4mh1[24m...[4mh5[24m  appears  in  order on its own line, centered,
              above the contents caption.  Page numbering restarts  at  1,  in
              register  format  “i”.  If the [1mOc [22mregister is true, numbering of
              these pages is suppressed.

              If [1mTC [22mis called with at most four arguments, it calls the  user‐
              defined  macro  [1mTX [22m(if defined) prior to formatting the contents
              caption, and [1mTY [22m(if defined) [4minstead[24m of formatting the  contents
              caption.

              Analogous  handling  of lists of figures, tables, equations, and
              exhibits is achieved by defining [1mTX[4m[22mxx[24m and [1mTY[4m[22mxx[24m macros, where  [4mxx[0m
              is  “FG”,  “TB”,  “EC”,  or  “EX”, respectively.  Similarly, the
              strings [1mLifg[22m, [1mLitb[22m, [1mLiex[22m, and [1mLiec [22mdetermine captions for  their
              respective lists.

       [1mTE     [22mTable end.  See [1mTS[22m.

       [1mTH     [22mEnd  table  heading.   It is repeated after page breaks within a
              table.  See [1mTS[22m.  The [1mN [22margument supported by DWB [4mmm[24m is  not  im‐
              plemented by [4mgroff[24m [4mmm.[0m

       [1mTL [22m[[4mcharging‐case‐number[24m [[4mfiling‐case‐number[24m]]
              Begin  document  title.  Input is collected into the title until
              [1mAF [22mor [1mAU [22mis called, and output as directed by  the  cover  page.
              [4mcharging‐case‐number[24m and [4mfiling‐case‐number[24m are saved for use in
              memorandum types 0 and 5.  See [1mMT[22m.

       [1mTM [4m[22mnumber[24m ...
              Declare technical memorandum number(s) used by [1mMT[22m.

       [1mTP     [22mIf  defined,  this macro is called in lieu of normal page header
              layout.  Headers and footers are formatted in a  separate  envi‐
              ronment.  See [1mEOP[22m.

              [1mStrings available to TP[0m
              ────────────────────────
              [1mTPh     [22margument to [1mPH[0m
              [1mTPeh    [22margument to [1mEH[0m
              [1mTPoh    [22margument to [1mOH[0m

       [1mTS [22m[[1mH[22m] Table  start.   Argument “H” tells [4mmm[24m that the table has a head‐
              ing.  See [1mTE[22m, [1mTH[22m, and [4mtbl[24m(1).

       [1mVERBON [22m[[4mformat[24m [[4mtype‐size[24m [[4mfont[24m]]]
              Begin verbatim display, where characters have equal width.  [4mfor‐[0m
              [4mmat[24m controls several parameters.  Add up the values  of  desired
              features; the default is [1m0[22m.  On typesetting devices, further ar‐
              guments  configure  the [4mtype‐size[24m in scaled points, and the face
              ([4mfont[24m); the default is [1mCR [22m(Courier roman).

              [1mValue   Effect[0m
              1       Disable the formatter’s escape character (\).
              2       Vertically space before the display.
              4       Vertically space after the display.
              8       Number output lines; call formatter’s  [1mnm  [22mrequest  with
                      arguments in string [1mVerbnm[22m.
              16      Indent by the amount stored in register [1mVerbin[22m.

       [1mVERBOFF[0m
              End verbatim display.

       [1mVL [22m[[4mtext‐indent[24m [[4mmark‐indent[24m [[1m1[22m]]]
              Begin variable‐item (or “tagged”) list.  Each item should supply
              its  own  mark,  or tag.  If the mark is wider than [4mmark‐indent,[0m
              one space separates  it  from  subsequent  text;  contrast  [1mBVL[22m.
              [4mtext‐indent[24m  sets  the  indentation of the text, and [4mmark‐indent[0m
              the distance from the current list indentation to the  mark.   A
              third  argument suppresses the blank line that normally precedes
              each list item.  Use [1mLI [22mto declare list items, and [1mLE [22mto end the
              list.

       [1mVM [22m[[1m-T[22m] [[4mtop[24m [[4mbottom[24m]]
              Vertical margin.  Increase the top and bottom margin by [4mtop[24m  and
              [4mbottom[24m, respectively.  If option [1m-T [22mis specified, set those mar‐
              gins to [4mtop[24m and [4mbottom[24m.  If no argument is given, reset the mar‐
              gin  to  zero, or to the default (“7v 5v”) if [1m-T [22mis used.  It is
              highly recommended that macros [1mTP [22mand/or [1mEOP [22mare defined if  us‐
              ing [1m-T [22mand setting top and/or bottom margin to less than the de‐
              fault.  This undocumented DWB [4mmm[24m macro is exposed by [4mgroff[24m [4mmm[24m to
              increase user control of page layout.

       [1mWA [22m[[4mwriter’s‐name[24m [[4mtitle[24m]]
              Specify  the writer(s) of an [1mLT [22mletter.  Input is collected into
              the writer’s address until [1mWA [22mis called, and then  output.   You
              can  specify  multiple  writers with empty [1mWA[22m/[1mWE [22mpairs; only the
              last address is used.  The arguments give each writer a name and
              title.

       [1mWC [22m[[4mformat[24m ...]
              Control width of footnotes and displays.

              [4m[1mformat[24m   Effect[0m
              [1mN        [22mequivalent to “[1m-WF -FF -WD[22m” (default)
              [1mWF       [22mset footnotes at full line length, even  in  two‐column
                       mode
              [1m-WF      [22mset footnotes using column line length
              [1mFF       [22mapply  width of first footnote to encountered to subse‐
                       quent ones
              [1m-FF      [22mfootnote width determined by [1mWF [22mand [1m-WF[0m
              [1mWD       [22mset displays at full line length,  even  in  two‐column
                       mode
              [1m-WD      [22mset displays using column line length

       [1mWE     [22mEnd the writer’s address begun with [1mWA[22m.

[1mStrings[0m
       Many  [4mmm[24m  strings  interpolate predefined, localizable text.  These are
       presented in quotation marks.

       [1mApp    [22m“APPENDIX”

       [1mApptxt [22mstores the [4mtitle[24m argument to the last [1mAPP [22mcall.

       [1mBU     [22minterpolates a bullet (see [1mBL[22m).

       [1mCi     [22mis a list of indentation amounts to use for  table  of  contents
              heading  levels,  overriding  their automatic computation.  Each
              word must be a horizontal measurement (like “[1m1i[22m”) and is  mapped
              one‐to‐one to heading levels 1, 2, and so on.

       [1mDT     [22mThe date; set by the [1mND [22mmacro (defaults to the date the document
              is formatted).  The format is the conventional one for the [4mgroff[0m
              locale, but see the [1mISODATE [22mmacro and [1mIso [22mregister.

       [1mEM     [22minterpolates an em dash.

       [1mF      [22minterpolates an automatically numbered footnote marker; the num‐
              ber  is  used by the next [1mFS [22mcall without an argument.  In [4mtroff[0m
              mode, the marker is superscripted; in [4mnroff[24m  mode,  it  is  sur‐
              rounded by square brackets.

       [1mH1txt  [22mUpdated by [1m.H [22mand [1m.HU [22mto the current heading text.  Also updated
              in table of contents & friends.

       [1mHF     [22massigns font identifiers, separated by spaces, to heading levels
              in  one‐to‐one  correspondence.   Each  identifier may be a font
              mounting position, font name, or style name.  Omitted values are
              assumed to be 1.  The default is “[1m2 2 2 2 2 2 2 2 2 2 2 2 2  2[22m”,
              which places all headings in italics.  DWB [4mmm[24m’s default was “[1m3 3[0m
              [1m2 2 2 2 2[22m”.

       [1mHP     [22massigns  type  sizes,  separated by spaces, to heading levels in
              one‐to‐one correspondence.  Each size is interpreted  in  scaled
              points;  zero  values  are translated to [1m10[22m.  Omitted values are
              assumed to be 0 (and are translated accordingly).   The  default
              is “[1m0 0 0 0 0 0 0 0 0 0 0 0 0 0[22m”.

       [1mIndex  [22m“INDEX”

       [1mLe     [22m“LIST OF EQUATIONS”

       [1mLetfc  [22m“Yours very truly,” (see [1mFC[22m)

       [1mLetapp [22m“APPROVED:” (see [1mAV[22m)

       [1mLetAT  [22m“ATTENTION:” (see [1mLO[22m)

       [1mLetCN  [22m“CONFIDENTIAL” (see [1mLO[22m)

       [1mLetdate[0m
              “Date” (see [1mAV[22m)

       [1mLetns  [22mis  a group of strings structuring the notations produced by [1mNS[22m.
              If the [4mcode[24m argument to [1mNS [22mhas no corresponding string, the  no‐
              tation   is   included   between   parentheses,   prefixed  with
              [1mLetns!copy[22m, and suffixed with [1mLetns!to[22m.  Observe the spaces  af‐
              ter “Copy” and before “to”.

              [1mNS code   String       Contents[0m
              0         Letns!0      Copy to
              1         Letns!1      Copy (with att.) to
              2         Letns!2      Copy (without att.) to
              3         Letns!3      Att.
              4         Letns!4      Atts.
              5         Letns!5      Enc.
              6         Letns!6      Encs.
              7         Letns!7      Under separate cover
              8         Letns!8      Letter to
              9         Letns!9      Memorandum to
              10        Letns!10     Copy (with atts.) to
              11        Letns!11     Copy (without atts.) to
              12        Letns!12     Abstract Only to
              13        Letns!13     Complete Memorandum to
              14        Letns!14     CC
              —         Letns!copy   Copy [4m(with[24m [4mtrailing[24m [4mspace)[0m
              —         Letns!to      to [4m(note[24m [4mleading[24m [4mspace)[0m

       [1mLetnsdef[0m
              Select  the notation format used by [1mNS [22mwhen it is given no argu‐
              ment.  The default is “[1m0[22m”.

       [1mLetRN  [22m“In reference to:” (see [1mLO[22m)

       [1mLetSA  [22m“To Whom It May Concern:” (see [1mLO[22m)

       [1mLetSJ  [22m“SUBJECT:” (see [1mLO[22m)

       [1mLf     [22m“LIST OF FIGURES”

       [1mLicon  [22m“CONTENTS”

       [1mLiec   [22m“Equation”

       [1mLiex   [22m“Exhibit”

       [1mLifg   [22m“Figure”

       [1mLitb   [22m“TABLE”

       [1mLt     [22m“LIST OF TABLES”

       [1mLx     [22m“LIST OF EXHIBITS”

       [1mMO1[22m...[1mMO12[0m
              “January” through “December”

       [1mQrf    [22m“See chapter \\*[Qrfh], page \\n[Qrfp].”

       [1mRf     [22minterpolates an automatically numbered reference mark; the  num‐
              ber  is  used by the next [1mRS [22mcall.  In [4mtroff[24m mode, the marker is
              superscripted; in [4mnroff[24m mode, it is surrounded by square  brack‐
              ets.

       [1mRp     [22m“REFERENCES”

       [1mSm     [22minterpolates ℠, the service mark sign.

       [1mTcst   [22minterpolates  an  indicator of the [1mTC [22mmacro’s processing status.
              If [1mTC [22mis not operating, it is empty.   User‐defined  [1mTP  [22mor  [1mEOP[0m
              macros might condition page headers or footers on its contents.

              [1mValue   Meaning[0m
              co      Table of contents
              fg      List of figures
              tb      List of tables
              ec      List of equations
              ex      List of exhibits
              ap      Appendix

       [1mTm     [22minterpolates ™, the trade mark sign.

       [1mVerbnm [22msupplies  argument(s)  to  the [1mnm [22mrequest employed by the [1mVERBON[0m
              macro.  The default is “1”.

[1mRegisters[0m
       Default register values, where meaningful, are  shown  in  parentheses.
       Many  are  also marked as Boolean‐valued, meaning that they are consid‐
       ered “true” (on, enabled) when they have a positive value, and  “false”
       (off, disabled) otherwise.

       [1m.mgm   [22mindicates that [4mgroff[24m [4mmm[24m is in use (Boolean‐valued; [1m1[22m).

       [1m:p     [22mis an auto‐incrementing footnote counter; see [1mFS[22m.

       [1m:R     [22mis an auto‐incrementing reference counter; see [1mRS[22m.

       [1mAph    [22mformats  an  appendix  heading (and title, if supplied); see [1mAPP[0m
              (Boolean‐valued; [1m1[22m).

       [1mAu     [22mincludes supplemental author information (the third  and  subse‐
              quent  arguments  to  [1mAU[22m)  in memorandum “from” information; see
              [1mCOVER [22mand [1mMT [22m(Boolean‐valued; [1m1[22m).

       [1mCl     [22msets the threshold for inclusion of headings in a table of  con‐
              tents.   Headings at levels above this value are excluded; see [1mH[0m
              and [1mTC [22m([1m2[22m).  The [1mCl [22mregister controls whether a heading is [4msaved[0m
              for output in the table of contents at  the  time  [1mH  [22mor  [1mHU  [22mis
              called;  if  you  change [1mCl[22m’s value immediately prior to calling
              [1mTC[22m, you are unlikely to get the result you want.

       [1mCp     [22msuppresses page breaks before lists of captioned equations,  ex‐
              hibits,  figures,  and  tables, and before an index; see [1mEC[22m, [1mEX[22m,
              [1mFG[22m, [1mTB[22m, and [1mINDP [22m(Boolean‐valued; [1m0[22m).

       [1mD      [22mproduces debugging information for the [4mmm[24m package on  the  stan‐
              dard error stream.  A value of 0 outputs nothing; 1 reports for‐
              matting  progress.  Higher values communicate internal state in‐
              formation of increasing verbosity ([1m0[22m).

       [1mDe     [22mcauses a page break after a floating display is output;  see  [1mDF[0m
              (Boolean‐valued; [1m0[22m).

       [1mDf     [22mconfigures  the behavior of [1mDF[22m.  The following values are recog‐
              nized; 4 and 5 do not override the [1mDe [22mregister ([1m5[22m).

              [1mValue   Effect[0m
              0       Flush pending displays at the end of each  section  when
                      section‐page  numbering  is active, otherwise at the end
                      of the document.
              1       Flush a pending display on the current page or column if
                      there is enough space, otherwise at the end of the docu‐
                      ment.
              2       Flush one pending display at the top  of  each  page  or
                      column.
              3       Flush a pending display on the current page or column if
                      there is enough space, otherwise at the top of the next.
              4       Flush as many pending displays as possible in a new page
                      or column.
              5       Fill  columns  or pages with flushed displays until none
                      remain.

       [1mDs     [22mputs vertical space in the amount of register [1mDsp  [22m(if  defined)
              or  [1mLsp  [22mbefore  and after each static display; see [1mDS [22m(Boolean‐
              valued; [1m1[22m).

       [1mDsp    [22mconfigures the amount of vertical space placed before and  after
              static displays; see [1mDS [22mand register [1mDs [22m([4mundefined[24m).

       [1mEc     [22mis an auto‐incrementing equation counter; see [1mEC[22m.

       [1mEj     [22msets  the threshold for page breaks (ejection) prior to the for‐
              mat of headings.  Headings at levels above this value are set on
              the same page and column if possible; see [1mH [22m([1m0[22m).

       [1mEq     [22maligns an equation label to the left of a display instead of the
              right (Boolean‐valued; [1m0[22m).

       [1mEx     [22mis an auto‐incrementing exhibit counter; see [1mEX[22m.

       [1mFg     [22mis an auto‐incrementing figure counter; see [1mFG[22m.

       [1mFs     [22mis multiplied by register [1mLsp [22mto vertically separate  footnotes;
              see [1mFS [22m([1m1[22m).

       [1mH1[22m...[1mH14[0m
              are  auto‐incrementing  counters  corresponding  to each heading
              level; see [1mH[22m.

       [1mH1dot  [22mappends a period to the number of a level  one  heading;  see  [1mH[0m
              (Boolean‐valued; [1m1[22m).

       [1mH1h    [22mis  a  copy  of A copy of register register [1mH1[22m, but it is incre‐
              mented just before a page break.  This can be useful in user‐de‐
              fined macros; see [1mH [22mand [1mHX[22m.

       [1mHb     [22msets the threshold for breaking  the  line  after  formatting  a
              heading.  Text after headings at levels above this value are set
              on the same output line if possible; see [1mH [22m([1m2[22m).

       [1mHc     [22msets  the threshold for centering a heading.  Headings at levels
              above this value use the prevailing alignment (that is, they are
              not centered); see [1mH [22m([1m0[22m).

       [1mHi     [22mconfigures the indentation of text after headings.  It does  not
              affect  “run‐in” headings.  The following values are recognized;
              see [1mH [22mand [1mP [22m([1m1[22m).

              [1mValue   Effect[0m
              0       no indentation
              1       indent per the paragraph type
              2       indent to align with heading title

       [1mHps    [22msets the heading level threshold for  application  of  preceding
              vertical  space;  see  [1mH[22m.  Headings at levels above the value in
              register [1mHps [22muse the amount of space in register [1mHps1[22m; otherwise
              that in [1mHps2[22m.  The value of [1mHps [22mshould be strictly greater  than
              that of [1mEj [22m([1m1[22m).

       [1mHps1   [22mconfigures  the  amount  of  vertical  space preceding a heading
              above the [1mHps [22mthreshold; see [1mH [22m([4mtroff[24m devices: [1m0.5v[22m;  [4mnroff[24m  de‐
              vices: [1m1v[22m).

       [1mHps2   [22mconfigures  the  amount of vertical space preceding a heading at
              or below the [1mHps [22mthreshold; see [1mH [22m([4mtroff[24m devices: [1m1v[22m; [4mnroff[24m  de‐
              vices: [1m2v[22m).

       [1mHs     [22msets  the  heading level threshold for application of succeeding
              vertical space.  If the heading level is greater  than  [1mHs[22m,  the
              heading  is  followed  by vertical space in the amount of regis‐
              ter [1mHss[22m; see [1mH [22m([1m2[22m).

       [1mHss    [22mis multiplied by register [1mLsp [22mto produce  vertical  space  after
              headings above the threshold in register [1mHs[22m; see [1mH [22m([1m1[22m).

       [1mHt     [22msuppresses  output  of  heading  level counters above the lowest
              when the heading is formatted; see [1mH [22m(Boolean‐valued; [1m0[22m).

       [1mHu     [22msets the heading level used by unnumbered headings; see [1mHU [22m([1m2[22m).

       [1mHy     [22menables automatic hyphenation of words (Boolean‐valued; [1m0[22m).

       [1mIso    [22mconfigures the use of ISO 8601 date format  if  specified  (with
              any value) on the command line; see [1mISODATE[22m.  The default is de‐
              termined by localization files.

       [1mL      [22mdefines  the  page length for the document, and must be set from
              the command line.  A scaling unit should be appended.   The  de‐
              fault is that of the selected [4mgroff[24m output device.

       [1mLe[0m
       [1mLf[0m
       [1mLt[0m
       [1mLx     [22mconfigure  the  report  of lists of equation, figure, table, and
              exhibit captions, respectively, after a table of  contents;  see
              [1mTC [22m(Boolean‐valued; [1mLe[22m: [1m0[22m; [1mLf[22m, [1mLt[22m, [1mLx[22m: [1m1[22m).

       [1mLetwam [22msets  the  maximum number of input lines permitted in a writer’s
              address; see [1mWA [22mand [1mWE [22m([1m14[22m).

       [1mLi     [22mconfigures the amount of indentation  in  ens  applied  to  list
              items; see [1mLI [22m([1m6[22m).

       [1mLimsp  [22minserts a space between the prefix and the mark in automatically
              numbered lists; see [1mAL [22m(Boolean‐valued; [1m1[22m).

       [1mLs     [22msets  a  threshold  for  placement of vertical space before list
              items.  If the list nesting level is greater than this value, no
              such spacing occurs; see [1mLI [22m([1m99[22m).

       [1mLsp    [22mconfigures the base amount of vertical space used for separation
              in the document.  [4mmm[24m applies  this  spacing  to  many  contexts,
              sometimes  with multipliers; see [1mDS[22m, [1mFS[22m, [1mH[22m, [1mLI[22m, and [1mP [22m([4mtroff[24m de‐
              vices: [1m0.5v[22m; [4mnroff[24m devices: [1m1v[22m).

       [1mN      [22mconfigures the header and footer placements used by [1mPH[22m.  The de‐
              fault footer is empty.  If “section‐page” numbering is selected,
              the default header becomes empty and the default footer  becomes
              “[4mx[24m‐[4my[24m”,  where [4mx[24m is is the section number (the number of the cur‐
              rent first‐level heading) and [4my[24m the page number within the  sec‐
              tion.   The  following values are recognized; for finer control,
              see [1mPH[22m, [1mPF[22m, [1mEH[22m, [1mEF[22m, [1mOH[22m, and [1mOF[22m, and registers [1mSectf  [22mand  [1mSectp[22m.
              Value 5 is a GNU extension ([1m0[22m).

              [1mValue   Effect[0m
              0       Set header on all pages.
              1       Move header to footer on page 1.
              2       Omit header on page 1.
              3       Use “section‐page” numbering style on all pages.
              4       Omit header on all pages.
              5       Use  “section‐page” and “section‐figure” numbering style
                      on all pages.

       [1mNp     [22mcauses paragraphs after first‐level headings (only) to  be  num‐
              bered  in  the format [4ms[24m.[4mp[24m, where [4ms[24m is is the section number (the
              number of the current first‐level heading) and [4mp[24m  is  the  para‐
              graph number, starting at 1; see [1mH [22mand [1mP [22m(Boolean‐valued; [1m0[22m).

       [1mO      [22mdefines  the  page  offset of the document, and must be set from
              the command line.  A scaling unit should be appended.   The  de‐
              fault  is [1m.75i [22mon terminal devices.  On typesetters, it is [1m.963i[0m
              or set to [1m1i [22mby the [4mpapersize.tmac[24m package; see [4mgroff_tmac[24m(5).

       [1mOc     [22msuppresses the appearance of page numbers in the table  of  con‐
              tents; see [1mTC [22m(Boolean‐valued; [1m0[22m).

       [1mOf     [22mselects a separator format within equation, exhibit, figure, and
              table  captions;  see  [1mEC[22m, [1mEX[22m, [1mFG[22m, and [1mTB[22m.  The following values
              are recognized; the spaces shown are unpaddable ([1m0[22m).

              [1mValue   Effect[0m
              0       ".  "
              1       " — "

       [1mP      [22minterpolates the current page number; it is the same  as  regis‐
              ter [1m% [22mexcept when “section‐page” numbering is enabled.

       [1mPi     [22mconfigures the amount of indentation in ens applied to the first
              line of a paragraph; see [1mP [22m([1m5[22m).

       [1mPgps   [22mcauses  the  type size and vertical spacing set by [1mS [22mto apply to
              headers and footers, overriding the [1mHP [22mstring.  If  not  set,  [1mS[0m
              calls  affect  headers and footers only when followed by [1mPH[22m, [1mPF[22m,
              [1mOH[22m, [1mEH[22m, [1mOF[22m, or [1mOE [22mcalls (Boolean‐valued; [1m1[22m).

       [1mPs     [22mis multiplied by register [1mLsp [22mto vertically separate paragraphs;
              see [1mP [22m([1m1[22m).

       [1mPt     [22mdetermines when a first‐line indentation is applied to  a  para‐
              graph; see [1mP [22m([1m0[22m).

              [1mValue   Effect[0m
              0       never
              1       always
              2       always, except immediately after [1mH[22m, [1mDE[22m, or [1mLE[0m

       [1mRef    [22mis  used  internally to control [4mmmroff[24m(1)’s two‐pass approach to
              index and reference management; see [1mINITI [22mand  [1mRS  [22m(Boolean‐val‐
              ued; [1m0[22m).

       [1mRpe    [22mconfigures the default page ejection policy for reference pages;
              see [1mRP [22m([1m0[22m).

              [1mValue   Effect[0m
              0       Break the page before and after the list of references.
              1       Suppress page break after the list.
              2       Suppress page break before the list.
              3       Suppress page breaks before and after the list.

       [1mS      [22mdefines the type size for the document, and must be set from the
              command  line.   A scaling unit should be appended; [1mp [22mis typical
              ([1m10p[22m).

       [1mSectf  [22mselects the “section‐figure” numbering style.  Its default is  [1m0[0m
              unless  register [1mN [22mis set to [1m5 [22mat the command line (Boolean‐val‐
              ued).

       [1mSectp  [22mselects the “section‐page” numbering style.  Its  default  is  [1m0[0m
              unless register [1mN [22mis set to [1m3 [22mor [1m5 [22mat the command line (Boolean‐
              valued).

       [1mSi     [22mconfigures the amount of display indentation in ens; see [1mDS [22m([1m5[22m).

       [1mTb     [22mis an auto‐incrementing table counter; see [1mTB[22m.

       [1mV      [22mdefines  the  vertical spacing for the document, and must be set
              from the command line.  A scaling unit should be appended; [1mp  [22mis
              typical.  The default vertical spacing is 120% of the type size.

       [1mVerbin [22mconfigures  the amount of indentation for verbatim displays when
              indentation is selected; see [1mVERBON [22m([1m5n[22m).

       [1mW      [22mdefines the “width” of the document (that is, the length  of  an
              output  line  with no indentation); it must be set from the com‐
              mand line.  A scaling unit  should  be  appended.   The  default
              is   [1m6i   [22mor   assigned   by  the  [4mpapersize.tmac[24m  package;  see
              [4mgroff_tmac[24m(5).

[1mInternals[0m
       The [1mLT [22mletter macros call further macros depending on the letter  type,
       with which they are suffixed.  It is therefore possible to define addi‐
       tional letter types, either in the territory‐specific macro file, or as
       local  additions.   [1mLT [22msets the registers [1mPt [22mand [1mPi [22mto 0 and 5, respec‐
       tively.  The following macros must be defined to support a  new  letter
       type.

       [1mlet@init_[4m[22mtype[0m
              [1mLT  [22mcalls  this macro to initialize any registers and other data
              needed by the letter type.

       [1mlet@head_[4m[22mtype[0m
              formats the letterhead; it is called instead of the  usual  page
              header macro.  Its definition should remove the alias [1mlet@header[0m
              unless the letterhead is desired on subsequent pages.

       [1mlet@sg_[4m[22mtype[24m [4mname[24m [4mtitle[24m [4mn[24m [4mis‐final[24m [[4mSG‐arg[24m ...]
              [1mSG  [22mcalls  this  macro only for letters; [1mMT [22mmemoranda have their
              own signature processing.  [4mname[24m and [4mtitle[24m are specified  through
              [1mWA[22m/[1mWE[22m.   [4mn[24m  is the index of the [4mn[24mth writer, and [4mis‐final[24m is true
              for the last writer to be listed.  Further [1mSG [22marguments are  ap‐
              pended to the signature line.

       [1mlet@fc_[4m[22mtype[24m [4mclosing[0m
              This  macro  is  called by [1mFC[22m, and has the formal closing as the
              argument.

       [1mLO [22mimplements letter options.  It requires that a string named  [1mLet[4m[22mtype[0m
       be  defined, where [4mtype[24m is the letter type.  [1mLO [22mthen assigns its second
       argument ([4mvalue[24m) to the string [1mlet*lo-[4m[22mtype[24m.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/m.tmac[0m
              is the [4mgroff[24m implementation of the memorandum macros.

       [4m/usr/share/groff/1.23.0/tmac/mm.tmac[0m
              is wrapper to load [4mm.tmac[24m.

       [4m/usr/share/groff/1.23.0/tmac/refer-mm.tmac[0m
              implements [4mrefer[24m(1) support for [4mmm[24m.

       [4m/usr/share/groff/1.23.0/tmac/mm/ms.cov[0m
              implements an [4mms[24m‐like cover sheet.

       [4m/usr/share/groff/1.23.0/tmac/mm/0.MT[0m
              implements memorandum types 0–3 and 6.

       [4m/usr/share/groff/1.23.0/tmac/mm/4.MT[0m
              implements memorandum type 4.

       [4m/usr/share/groff/1.23.0/tmac/mm/5.MT[0m
              implements memorandum type 5.

       [4m/usr/share/groff/1.23.0/tmac/mm/locale[0m
              performs any (further) desired necessary localization; empty  by
              default.

[1mAuthors[0m
       The GNU version of the [4mmm[24m macro package was written by Jörgen Hägg ⟨jh@
       axis.se⟩ of Lund, Sweden.

[1mSee also[0m
       [4mMM[24m [4m-[24m [4mA[24m [4mMacro[24m [4mPackage[24m [4mfor[24m [4mGenerating[24m [4mDocuments[24m ⟨https://tkurtbond.github
       .io/troff/mm-all.pdf⟩,  the  DWB  3.3 [4mmm[24m manual, introduces the package
       but does not document GNU extensions.

       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher  and  Werner
       Lemberg,  is the primary [4mgroff[24m manual.  You can browse it interactively
       with “info groff”.

       [4mgroff[24m(1), [4mtroff[24m(1), [4mtbl[24m(1), [4mpic[24m(1), [4meqn[24m(1), [4mrefer[24m(1), [4mgroff_mmse[24m(7)

groff 1.23.0                      5 July 2023                      [4mgroff_mm[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_mmse[24m(7)           Handbok för diverse information          [4mgroff_mmse[24m(7)

[1mNamn[0m
       groff_mmse - svenska ”memorandum” makro för GNU [4mroff[0m

[1mSyntax[0m
       [1mgroff -mmse [22m[[4mflaggor[24m ...] [[4mfiler[24m ...]
       [1mgroff -m mmse [22m[[4mflaggor[24m ...] [[4mfiler[24m ...]

[1mBeskrivning[0m
       [4mmmse[24m är en svensk variant av [4mmm[24m. Alla texter är översatta. En  A4  sida
       får  text som är 13 cm bred, 3,5 cm indragning samt är 28,5 cm hög. Det
       finns stöd för brevuppställning enligt svensk standard för vänster  och
       högerjusterad text.

       [1mCOVER  [22mkan  använda [4mse_ms[24m som argument. Detta ger ett svenskt försätts‐
       blad. Se [4mgroff_mm[24m(7) för övriga detaljer.

[1mBrev[0m
       Tillgängliga brevtyper:

       [1m.LT SVV[0m
              Vänsterställd löptext  med  adressat  i  position  T0  (vänster‐
              ställt).

       [1m.LT SVH[0m
              Högerställd  löptext med adressat i position T4 (passar fönster‐
              kuvert).

       Följande extra LO‐variabler används.

       [1m.LO DNAMN [4m[22mnamn[0m
              Anger dokumentets namn.

       [1m.LO MDAT [4m[22mdatum[0m
              Mottagarens datum, anges under [1mErt datum: [22m([1mLetMDAT[22m).

       [1m.LO BIL [4m[22msträng[0m
              Anger bilaga, nummer eller sträng med [1mBilaga [22m([1mLetBIL[22m)  som  pre‐
              fix.

       [1m.LO KOMP [4m[22mtext[0m
              Anger kompletteringsuppgift.

       [1m.LO DBET [4m[22mbeteckning[0m
              Anger dokumentbeteckning eller dokumentnummer.

       [1m.LO BET [4m[22mbeteckning[0m
              Anger  beteckning (ärendebeteckning i form av diarienummer eller
              liknande).

       [1m.LO SIDOR [4m[22mantal[0m
              Anger totala antalet sidor och skrivs ut  efter  sidnumret  inom
              parenteser.

       Om  makrot [1m.TP [22mär definierat anropas det efter utskrift av brevhuvudet.
       Där lägger man lämpligen in postadress och annat som brevfot.

[1mSkrivet av[0m
       Jörgen Hägg, Lund, Sweden <Jorgen.Hagg@axis.se>

[1mFiler[0m
       [4m/usr/share/groff/1.23.0/tmac/mse.tmac[0m

       [4m/usr/share/groff/1.23.0/tmac/mm/se_[24m*[4m.cov[0m

[1mSe också[0m
       [4mgroff_mm[24m(7)

groff 1.23.0                      5 July 2023                    [4mgroff_mmse[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_mom[24m(7)           Miscellaneous Information Manual           [4mgroff_mom[24m(7)

[1mName[0m
       groff_mom - modern macros for document composition with GNU [4mroff[0m

[1mSynopsis[0m
       [1mgroff -mom [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff -m mom [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       [4mmom[24m is a macro set for [4mgroff[24m, designed primarily to  prepare  documents
       for  PDF and PostScript output.  [4mmom[24m provides macros in two categories:
       typesetting and document processing.   The  former  provide  access  to
       [4mgroff[24m’s  typesetting  capabilities  in  ways that are simpler to master
       than [4mgroff[24m’s requests and escape sequences.  The latter provide  highly
       customizable  markup tags that allow the user to design and output pro‐
       fessional‐looking documents with a minimum of typesetting intervention.

       Files processed with [4mpdfmom[24m(1) produce PDF  documents.   The  documents
       include a PDF outline that appears in the navigation pane panel of doc‐
       ument viewers, and may contain clickable internal and external links.

       Normally.   [4mgroff[24m’s  native  PDF driver, [4mgropdf[24m(1), is used to generate
       the output.  When [4mpdfmom[24m is given the “[1m-T ps[22m” option, it still produces
       PDF, but processing is delegated to [4mpdfroff[24m, which uses  [4mgroff[24m’s  Post‐
       Script driver, [4mgrops[24m(1).  Not all PDF features are available when [1m-T ps[0m
       is given; its primary use is to allow processing of files with embedded
       PostScript images.

       Files processed with [1mgroff -mom [22m(or [1m-m mom[22m) format for the device spec‐
       ified  with  the  [1m-T  [22moption.  (In this installation, [1mps [22mis the default
       output device.)

       [4mmom[24m comes with her own comprehensive documentation in HTML.  A PDF man‐
       ual, “Producing PDFs with [4mgroff[24m and [4mmom[24m”, discusses preparation of  PDF
       documents with [4mmom[24m in detail.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/mom.tmac[0m
              is  a  wrapper  enabling the package to be loaded with “[1mgroff -m[0m
              [1mmom[22m”.

       [4m/usr/share/groff/1.23.0/tmac/om.tmac[0m
              implements the package.

       [4m/usr/share/doc/groff-1.23.0/html/mom/toc.html[0m
              is the entry point to the HTML documentation.

       [4m/usr/share/doc/groff-1.23.0/pdf/mom-pdf.pdf[0m
              is “Producing PDFs with [4mgroff[24m and [4mmom[24m”, by Deri James and  Peter
              Schaffter.

       [4m/usr/share/doc/groff-1.23.0/examples/mom/[24m*[4m.mom[0m
              are examples of [4mmom[24m usage.

[1mReference[0m
   [1mEscape sequences[0m
       [1m\*[[4m[22m<colorname>[24m[1m][0m
              begin using an initialized colour inline

       [1m\*[BCK [4m[22mn[24m[1m][0m
              move backward in a line

       [1m\*[BOLDER][0m
              invoke pseudo bold inline (related to macro [1m.SETBOLDER[22m)

       [1m\*[BOLDERX][0m
              off pseudo bold inline (related to macro [1m.SETBOLDER[22m)

       [1m\*[BU [4m[22mn[24m[1m][0m
              move  characters  pairs closer together inline (related to macro
              [1m.KERN[22m)

       [1m\*[COND][0m
              invoke pseudo condensing inline (related to macro [1m.CONDENSE[22m)

       [1m\*[CONDX][0m
              off pseudo condensing inline (related to macro [1m.CONDENSE[22m)

       [1m\*[CONDSUP][22m...[1m\*[CONDSUPX][0m
              pseudo‐condensed superscript

       [1m\*[DOWN [4m[22mn[24m[1m][0m
              temporarily move downward in a line

       [1m\*[EN-MARK][0m
              mark initial line of a range of line numbers (for use with  line
              numbered endnotes)

       [1m\*[EXT][0m
              invoke pseudo extending inline (related to macro [1m.EXTEND[22m)

       [1m\*[EXTX][0m
              off pseudo condensing inline (related to macro [1m.EXTEND[22m)

       [1m\*[EXTSUP][22m...[1m\*[EXTSUPX][0m
              pseudo extended superscript

       [1m\*[FU [4m[22mn[24m[1m][0m
              move  characters  pairs  further  apart inline (related to macro
              [1m.KERN[22m)

       [1m\*[FWD [4m[22mn[24m[1m][0m
              move forward in a line

       [1m\*[LEADER][0m
              insert leaders at the end of a line

       [1m\*[RULE][0m
              draw a full measure rule

       [1m\*[SIZE [4m[22mn[24m[1m][0m
              change the point size inline (related to macro [1m.PT_SIZE[22m)

       [1m\*[SLANT][0m
              invoke pseudo italic inline (related to macro [1m.SETSLANT[22m)

       [1m\*[SLANTX][0m
              off pseudo italic inline (related to macro [1m.SETSLANT[22m)

       [1m\*[ST[4m[22m<n>[24m[1m][22m...[1m\*[ST[4m[22m<n>[24m[1mX][0m
              string tabs (mark tab positions inline)

       [1m\*[SUP][22m...[1m\*[SUPX][0m
              superscript

       [1m\*[TB+][0m
              inline escape for [1m.TN [22m([4mTab[24m [4mNext[24m)

       [1m\*[UL][22m...[1m\*[ULX][0m
              invoke underlining inline (fixed width fonts only)

       [1m\*[UP [4m[22mn[24m[1m][0m
              temporarily move upward in a line

   [1mMacros[0m
       [1m.AUTOLEAD[0m
              set the linespacing relative to the point size

       [1m.B_MARGIN[0m
              set a bottom margin

       [1m.BR    [22mbreak a justified line

       [1m.CENTER[0m
              set line‐by‐line quad centre

       [1m.CONDENSE[0m
              set the amount to pseudo condense

       [1m.EL    [22mbreak a line without advancing on the page

       [1m.EXTEND[0m
              set the amount to pseudo extend

       [1m.FALLBACK_FONT[0m
              establish a fallback font (for missing fonts)

       [1m.FAM   [22malias to [1m.FAMILY[0m

       [1m.FAMILY [4m[22m<family>[0m
              set the [4mfamily[24m [4mtype[0m

       [1m.FT    [22mset the font style (roman, italic, etc.)

       [1m.HI [ [4m[22m<measure>[24m [1m][0m
              hanging indent

       [1m.HY    [22mautomatic hyphenation on/off

       [1m.HY_SET[0m
              set automatic hyphenation parameters

       [1m.IB [ [4m[22m<left[24m [4mmeasure>[24m [4m<right[24m [4mmeasure>[24m [1m][0m
              indent both

       [1m.IBX [ CLEAR ][0m
              exit indent both

       [1m.IL [ [4m[22m<measure>[24m [1m][0m
              indent left

       [1m.ILX [ CLEAR ][0m
              exit indent left

       [1m.IQ [ CLEAR ][0m
              quit any/all indents

       [1m.IR [ [4m[22m<measure>[24m [1m][0m
              indent right

       [1m.IRX [ CLEAR ][0m
              exit indent right

       [1m.JUSTIFY[0m
              justify text to both margins

       [1m.KERN  [22mautomatic character pair kerning on/off

       [1m.L_MARGIN[0m
              set a left margin (page offset)

       [1m.LEFT  [22mset line‐by‐line quad left

       [1m.LL    [22mset a line length

       [1m.LS    [22mset a linespacing (leading)

       [1m.PAGE  [22mset explicit page dimensions and margins

       [1m.PAGEWIDTH[0m
              set a custom page width

       [1m.PAGELENGTH[0m
              set a custom page length

       [1m.PAPER [4m[22m<paper_type>[0m
              set common paper sizes (letter, A4, etc)

       [1m.PT_SIZE[0m
              set the point size

       [1m.QUAD  [22m"justify" text left, centre, or right

       [1m.R_MARGIN[0m
              set a right margin

       [1m.RIGHT [22mset line‐by‐line quad right

       [1m.SETBOLDER[0m
              set the amount of emboldening

       [1m.SETSLANT[0m
              set the degree of slant

       [1m.SPREAD[0m
              force justify a line

       [1m.SS    [22mset the sentence space size

       [1m.T_MARGIN[0m
              set a top margin

       [1m.TI [ [4m[22m<measure>[24m [1m][0m
              temporary left indent

       [1m.WS    [22mset the minimum word space size

[1mDocumentation of details[0m
   [1mDetails of inline escape sequences in alphabetical order[0m
       [1m\*[[4m[22m<colorname>[24m[1m][0m
              begin using an initialized colour inline

       [1m\*[BCK [4m[22mn[24m[1m][0m
              move backward in a line

       [1m\*[BOLDER][0m
       [1m\*[BOLDERX][0m
              Emboldening on/off

              [1m\*[BOLDER] [22mbegins emboldening type.  [1m\*[BOLDERX] [22mturns the  fea‐
              ture  off.   Both  are  inline escape sequences; therefore, they
              should not appear as separate lines, but rather be  embedded  in
              text lines, like this:
                     Not [1m\*[BOLDER][22meverything[1m\*[BOLDERX] [22mis as it seems.

              Alternatively,  if  you  wanted  the  whole line emboldened, you
              should do
                     [1m\*[BOLDER][22mNot everything is as it seems.[1m\*[BOLDERX][0m
              Once [1m\*[BOLDER] [22mis invoked, it remains in  effect  until  turned
              off.

              Note:  If  you’re  using  the  document  processing  macros with
              [1m.PRINTSTYLE TYPEWRITE[22m, [4mmom[24m ignores [1m\*[BOLDER] [22mrequests.

       [1m\*[BU [4m[22mn[24m[1m][0m
              move characters pairs closer together inline (related  to  macro
              [1m.KERN[22m)

       [1m\*[COND][0m
       [1m\*[CONDX][0m
              Pseudo‐condensing on/off

              [1m\*[COND]  [22mbegins  pseudo‐condensing  type.   [1m\*[CONDX] [22mturns the
              feature off.  Both are inline escape sequences; therefore,  they
              should  not  appear as separate lines, but rather be embedded in
              text lines, like this:
                     [1m\*[COND][4m[22mNot[24m [4meverything[24m [4mis[24m [4mas[24m [4mit[24m [4mseems.[24m[1m\*[CONDX][0m
              [1m\*[COND] [22mremains in effect until you turn it off with [1m\*[CONDX][22m.

              IMPORTANT: You must turn [1m\*[COND] [22moff before making any  changes
              to the point size of your type, either via the [1m.PT_SIZE [22mmacro or
              with  the  [1m\s [22minline escape sequence.  If you wish the new point
              size to be pseudo‐condensed, simply reinvoke [1m\*[COND] [22mafterward.
              Equally, [1m\*[COND] [22mmust be turned off before  changing  the  con‐
              dense percentage with [1m.CONDENSE[22m.

              Note:  If  you’re  using  the  document  processing  macros with
              [1m.PRINTSTYLE TYPEWRITE[22m, [4mmom[24m ignores [1m\*[COND] [22mrequests.

       [1m\*[CONDSUP][22m...[1m\*[CONDSUPX][0m
              pseudo‐condensed superscript

       [1m\*[DOWN [4m[22mn[24m[1m][0m
              temporarily move downward in a line

       [1m\*[EN-MARK][0m
              mark initial line of a range of line numbers (for use with  line
              numbered endnotes)

       [1m\*[EXT][0m
       [1m\*[EXTX][0m
              Pseudo‐extending on/off

              [1m\*[EXT]  [22mbegins  pseudo‐extending type.  [1m\*[EXTX] [22mturns the fea‐
              ture off.  Both are inline  escape  sequences;  therefore,  they
              should  not  appear as separate lines, but rather be embedded in
              text lines, like this:
                     [1m\*[EXT][4m[22mNot[24m [4meverything[24m [4mis[24m [4mas[24m [4mit[24m [4mseems.[24m[1m\*[EXTX][0m
              [1m\*[EXT] [22mremains in effect until you turn it off with [1m\*[EXTX][22m.

              IMPORTANT: You must turn [1m\*[EXT] [22moff before making  any  changes
              to the point size of your type, either via the [1m.PT_SIZE [22mmacro or
              with  the  [1m\s [22minline escape sequence.  If you wish the new point
              size to be [4mpseudo‐extended[24m, simply reinvoke  [1m\*[EXT]  [22mafterward.
              Equally,  [1m\*[EXT]  [22mmust be turned off before changing the extend
              percentage with [1m.EXTEND[22m.

              Note: If you are  using  the  document  processing  macros  with
              [1m.PRINTSTYLE TYPEWRITE[22m, [4mmom[24m ignores [1m\*[EXT] [22mrequests.

       [1m\*[EXTSUP][22m...[1m\*[EXTSUPX][0m
              pseudo extended superscript

       [1m\*[FU [4m[22mn[24m[1m][0m
              move  characters  pairs  further  apart inline (related to macro
              [1m.KERN[22m)

       [1m\*[FWD [4m[22mn[24m[1m][0m
              move forward in a line

       [1m\*[LEADER][0m
              insert leaders at the end of a line

       [1m\*[RULE][0m
              draw a full measure rule

       [1m\*[SIZE [4m[22mn[24m[1m][0m
              change the point size inline (related to macro [1m.PT_SIZE[22m)

       [1m\*[SLANT][0m
       [1m\*[SLANTX][0m
              Pseudo italic on/off

              [1m\*[SLANT] [22mbegins [4mpseudo‐italicizing[24m [4mtype[24m.  [1m\*[SLANTX] [22mturns  the
              feature  off.  Both are inline escape sequences; therefore, they
              should not appear as separate lines, but rather be  embedded  in
              text lines, like this:
                     Not [1m\*[SLANT][22meverything[1m\*[SLANTX] [22mis as it seems.

              Alternatively,  if  you wanted the whole line [4mpseudo‐italicized[24m,
              you’d do
                     [1m\*[SLANT][22mNot everything is as it seems.[1m\*[SLANTX][0m

              Once [1m\*[SLANT] [22mis invoked, it remains  in  effect  until  turned
              off.

              Note:  If  you’re  using  the  document  processing  macros with
              [1m.PRINTSTYLE TYPEWRITE[22m, [4mmom[24m underlines pseudo‐italics by default.
              To   change   this   behaviour,   use    the    special    macro
              [1m.SLANT_MEANS_SLANT[22m.

       [1m\*[ST[4m[22m<number>[24m[1m][22m...[1m\*[ST[4m[22m<number>[24m[1mX][0m
              Mark positions of string tabs

              The  [4mquad[24m  direction  must  be  [1mLEFT  [22mor  [1mJUSTIFY [22m(see [1m.QUAD [22mand
              [1m.JUSTIFY[22m) or the [4mno‐fill[24m [4mmode[24m set to [1mLEFT [22min order for these in‐
              lines to function properly.  Please see [4mIMPORTANT[24m, below.

              String tabs need to be marked off with inline  escape  sequences
              before being set up with the [1m.ST [22mmacro.  Any input line may con‐
              tain  string  tab  markers.   [4m<number>[24m, above, means the numeric
              identifier of the tab.

              The following shows a sample input line with string tab markers.
                     [1m\*[ST1][22mDe minimus[1m\*[ST1X][22mnon curat[1m\*[ST2][22mlex[1m\*[ST2X][22m.

              String [4mtab[24m [4m1[24m begins at the start of the line and ends after  the
              word [4mtime[24m.  String [4mtab[24m [4m2[24m starts at [4mgood[24m and ends after [4mmen[24m.  [4mIn‐[0m
              [4mline[24m [4mescape[24m [4msequences[24m (e.g., [4mfont[24m or [4mpoint[24m [4msize[24m [4mchanges[24m, or hor‐
              izontal  movements,  including  padding)  are taken into account
              when [4mmom[24m determines the [4mposition[24m and [4mlength[24m of [4mstring[24m [4mtabs[24m.

              Up to nineteen string tabs may be marked (not necessarily all on
              the same line, of course), and they must be numbered  between  1
              and 19.

              Once  string  tabs have been marked in input lines, they have to
              be [4mset[24m with [1m.ST[22m, after which they may be called, by number, with
              [1m.TAB[22m.

              Note: Lines with string tabs marked off in them are normal input
              lines, i.e. they get printed, just like any input line.  If  you
              want  to  set  up string tabs without the line printing, use the
              [1m.SILENT [22mmacro.

              [4mIMPORTANT:[24m Owing to the way  [4mgroff[24m  processes  input  lines  and
              turns  them  into  output  lines,  it is not possible for [4mmom[24m to
              [4mguess[24m the correct starting position of string tabs marked off in
              lines that are centered or set flush right.

              Equally, she cannot guess the starting position  if  a  line  is
              fully justified and broken with [1m.SPREAD[22m.

              In  other  words,  in order to use string tabs, [1mLEFT [22mmust be ac‐
              tive, or, if [1m.QUAD LEFT [22mor [1mJUSTIFY [22mare active, the line on which
              the [4mstring[24m [4mtabs[24m are marked must be broken [4mmanually[24m with [1m.BR [22m(but
              not [1m.SPREAD[22m).

              To circumvent this behaviour, I recommend using the [1mPAD  [22mto  set
              up string tabs in centered or flush right lines.  Say, for exam‐
              ple,  you  want  to use a [4mstring[24m [4mtab[24m to [4munderscore[24m the text of a
              centered line with a rule.  Rather than this,
                     [1m.CENTER[0m
                     [1m\*[ST1]A line of text\*[ST1X]\c[0m
                     [1m.EL[0m
                     [1m.ST 1[0m
                     [1m.TAB 1[0m
                     [1m.PT_SIZE 24[0m
                     [1m.ALD 3p[0m
                     [1m\*[RULE][0m
                     [1m.RLD 3p[0m
                     [1m.TQ[0m
              you should do:
                     .QUAD CENTER
                     .PAD "#\*[ST1]A line of text\*[ST1X]#"
                     .EL
                     .ST 1
                     .TAB 1
                     .PT_SIZE 24
                     .ALD 3p
                     \" You can't use \*[UP] or \*[DOWN] with \*[RULE].
                     .RLD 3p
                     .TQ

       [1m\*[SUP][22m...[1m\*[SUPX][0m
              superscript

       [1m\*[TB+][0m
              Inline escape for [1m.TN [22m([4mTab[24m [4mNext[24m)

       [1m\*[UL][22m...[1m\*[ULX][0m
              invoke underlining inline (fixed width fonts only)

       [1m\*[UP [4m[22mn[24m[1m][0m
              temporarily move upward in a line

   [1mDetails of macros in alphabetical order[0m
       [1m.AUTOLEAD[0m
              set the linespacing relative to the point size

       [1m.B_MARGIN [4m[22m<bottom[24m [4mmargin>[0m
              Bottom Margin

              Requires a unit of measure

              [1m.B_MARGIN [22msets a nominal position at the bottom of the page  be‐
              yond which you don’t want your type to go.  When the bottom mar‐
              gin  is  reached,  [4mmom[24m  starts a new page.  [1m.B_MARGIN requires a[0m
              [1munit of measure.  [22mDecimal fractions are allowed.  To set a nomi‐
              nal bottom margin of 3/4 inch, enter
                     [1m.B_MARGIN .75i[0m

              Obviously, if you haven’t spaced the type on your pages so  that
              the  last  lines fall perfectly at the bottom margin, the margin
              will vary from page to page.  Usually, but not always, the  last
              line of type that fits on a page before the bottom margin causes
              mom to start a new page.

              Occasionally,  owing  to  a  peculiarity in [4mgroff[24m, an extra line
              will fall below the nominal bottom margin.  If you’re using  the
              document processing macros, this is unlikely to happen; the doc‐
              ument  processing macros are very hard‐nosed about aligning bot‐
              tom margins.

              Note: The meaning of [1m.B_MARGIN [22mis slightly different when you’re
              using the document processing macros.

       [1m.FALLBACK_FONT [4m[22m<fallback[24m [4mfont>[24m [1m[ ABORT | WARN ][0m
              Fallback Font

              In the event that you pass an invalid argument to [1m.FAMILY  [22m(i.e.
              a non‐existent [4mfamily[24m), [4mmom[24m, by default, uses the [4mfallback[24m [4mfont[24m,
              [1mCourier  Medium Roman [22m([1mCR[22m), in order to continue processing your
              file.

              If you’d prefer another [4mfallback[24m [4mfont[24m, pass  [1m.FALLBACK_FONT  [22mthe
              full  [4mfamily+font[24m  [4mname[24m of the [4mfont[24m you’d like.  For example, if
              you’d rather the [4mfallback[24m [4mfont[24m were [1mTimes Roman Medium Roman[22m,
                     [1m.FALLBACK_FONT TR[0m
              would do the trick.

              [1mMom [22missues a warning whenever a [4mfont[24m [4mstyle[24m [4mset[24m with [1m.FT [22mdoes not
              exist, either because you haven’t registered the  style  or  be‐
              cause  the  [4mfont[24m  [4mstyle[24m does not exist in the current [4mfamily[24m [4mset[0m
              with [1m.FAMILY[22m.  By default, [1mmom [22mthen aborts, which allows you  to
              correct the problem.

              If  you’d  prefer  that [1mmom [22mnot abort on non‐existent [4mfonts[24m, but
              rather continue processing using a [4mfallback[24m [4mfont[24m, you  can  pass
              [1m.FALLBACK_FONT  [22mthe  argument [1mWARN[22m, either by itself, or in con‐
              junction with your chosen [4mfallback[24m [4mfont[24m[1m.[0m

              Some examples of invoking [1m.FALLBACK_FONT[22m:

              [1m.FALLBACK_FONT WARN[0m
                     [4mmom[24m will issue a warning whenever you  try  to  access  a
                     non‐existent  [4mfont[24m but will continue processing your file
                     with the default [4mfallback[24m [4mfont[24m, [1mCourier Medium Roman[22m.

              [1m.FALLBACK_FONT TR WARN[0m
                     [1mmom [22mwill issue a warning whenever you  try  to  access  a
                     non‐existent  [4mfont[24m but will continue processing your file
                     with a [4mfallback[24m [4mfont[24m of [1mTimes Roman Medium  Roman[22m;  addi‐
                     tionally,  [1mTR  [22mwill be the [4mfallback[24m [4mfont[24m whenever you try
                     to access a [4mfamily[24m that does not exist.

              [1m.FALLBACK_FONT TR ABORT[0m
                     [1mmom [22mwill abort whenever you try to access a  non‐existent
                     [1mfont[22m,  and will use the [4mfallback[24m [4mfont[24m [1mTR [22mwhenever you try
                     to access a [4mfamily[24m that does not  exist.   If,  for  some
                     reason,   you   want  to  revert  to  [1mABORT[22m,  just  enter
                     [1m".FALLBACK_FONT ABORT" [22mand [4mmom[24m will once again  abort  on
                     [4mfont[24m [4merrors[24m.

       [1m.FAM [4m[22m<family>[0m
              Type Family, alias of [1m.FAMILY[0m

       [1m.FAMILY [4m[22m<family>[0m
              Type Family, alias of [1m.FAM[0m

              [1m.FAMILY  [22mtakes  one  argument:  the name of the [4mfamily[24m you want.
              [4mGroff[24m comes with a small set of basic families, each  identified
              by a 1‐, 2‐ or 3‐letter mnemonic.  The standard families are:
                     [1mA   = Avant Garde[0m
                     [1mBM  = Bookman[0m
                     [1mH   = Helvetica[0m
                     [1mHN  = Helvetica Narrow[0m
                     [1mN   = New Century Schoolbook[0m
                     [1mP   = Palatino[0m
                     [1mT   = Times Roman[0m
                     [1mZCM = Zapf Chancery[0m

              The  argument  you  pass  to  [1m.FAMILY [22mis the identifier at left,
              above.  For example, if you want [1mHelvetica[22m, enter
                     [1m.FAMILY H[0m

              Note: The font macro ([1m.FT[22m) lets you specify both the type [4mfamily[0m
              and the desired font with a single macro.  While  this  saves  a
              few  keystrokes,  I  recommend using [1m.FAMILY for [4m[22mfamily[24m, and [1m.FT[0m
              [1mfor [4m[22mfont[24m, except where doing so is genuinely inconvenient.  [1mZCM[22m,
              for example, only exists in one style: [1mItalic [22m([1mI[22m).

              Therefore,
                     [1m.FT ZCMI[0m
              makes more sense than setting the [4mfamily[24m to  [1mZCM[22m,  then  setting
              the [4mfont[24m to [4mI[24m.

              Additional  note:  If  you  are running a [4mgroff[24m version prior to
              1.19.2, you must follow all [1m.FAMILY [22mrequests with a [1m.FT [22mrequest,
              otherwise [4mmom[24m will set all type up to the next  [1m.FT  [22mrequest  in
              the fallback font.

              If  you  are  running [4mgroff[24m 1.19.2 or later, when you invoke the
              [1m.FAMILY [22mmacro, [4mmom[24m [4mremembers[24m the font style [1m([22mRoman[1m, Italic[22m, etc)
              currently in use (if the font style exists in  the  new  [4mfamily[24m)
              and  will continue to use the same font style in the new family.
              For example:
                     [1m.FAMILY BM [4m[22m\"[24m [4mBookman[24m [4mfamily[0m
                     [1m.FT I [4m[22m\"[24m [4mMedium[24m [4mItalic[0m
                     [4m<some[24m [4mtext>[24m [4m\"[24m [4mBookman[24m [4mMedium[24m [4mItalic[0m
                     [1m.FAMILY H [4m[22m\"[24m [4mHelvetica[24m [4mfamily[0m
                     [4m<more[24m [4mtext>[24m [4m\"[24m [4mHelvetica[24m [4mMedium[24m [4mItalic[0m

              However, if the font style does not exist in the new family, [4mmom[0m
              will set all subsequent type in the fallback font  (by  default,
              [1mCourier  Medium Roman[22m) until she encounters a [1m.FT [22mrequest that’s
              valid for the [4mfamily[24m.

              For example, assuming you don’t have the font  [1mMedium  Condensed[0m
              [1mRoman [22m([4mmom[24m extension [4mCD[24m) in the [4mHelvetica[24m [4mfamily[24m:
                     [1m.FAMILY UN [4m[22m\"[24m [4mUnivers[24m [4mfamily[0m
                     [1m.FT CD [4m[22m\"[24m [4mMedium[24m [4mCondensed[0m
                     [4m<some[24m [4mtext>[24m [4m\"[24m [4mUnivers[24m [4mMedium[24m [4mCondensed[0m
                     [1m.FAMILY H [4m[22m\"[24m [4mHelvetica[24m [4mfamily[0m
                     [4m<more[24m [4mtext>[24m [4m\"[24m [4mCourier[24m [4mMedium[24m [4mRoman![0m

              In  the  above example, you must follow [1m.FAMILY H [22mwith a [1m.FT [22mre‐
              quest that’s valid for [1mHelvetica[22m.

              Please see the Appendices, [4mAdding[24m [4mfonts[24m [4mto[24m [4mgroff[24m,  for  informa‐
              tion on adding fonts and families to [4mgroff[24m,[4mas[24mwell[4mas[24mto see a list
              of  the  extensions  [4mmom[24m  provides  to [4mgroff[24m’s basic [1mR[22m, [1mI[22m, [1mB[22m, [1mBI[0m
              styles.

              Suggestion: When adding [4mfamilies[24m [4mto[24m [4mgroff[24m, I recommend following
              the established standard for the naming families and fonts.  For
              example, if you add the [1mGaramond [22mfamily, name the font files
                     [1mGARAMONDR[0m
                     [1mGARAMONDI[0m
                     [1mGARAMONDB[0m
                     [1mGARAMONDBI[0m
              [1mGARAMOND then becomes a valid [4m[22mfamily[24m [4mname[24m you can pass to [1m.FAMI‐[0m
              [1mLY[22m.  (You could, of course, shorten [1mGARAMOND [22mto just [1mG[22m, or  [1mGD[22m.)
              [1mR[22m,  [1mI[22m,  [1mB[22m, and [1mBI [22mafter [1mGARAMOND [22mare the [4mroman[24m, [4mitalic[24m, [4mbold[24m and
              [4mbold‐italic[24m fonts respectively.

       [1m.FONT R | B | BI | [4m[22m<any[24m [4mother[24m [4mvalid[24m [4mfont[24m [4mstyle>[0m
              Alias to [1m.FT[0m

       [1m.FT R | B | BI | [4m[22m<any[24m [4mother[24m [4mvalid[24m [4mfont[24m [4mstyle>[0m
              Set font

              By default, [4mgroff[24m permits [1m.FT [22mto take one of four possible argu‐
              ments specifying the desired font:
                     [1mR = (Medium) Roman[0m
                     [1mI = (Medium) Italic[0m
                     [1mB = Bold (Roman)[0m
                     [1mBI = Bold Italic[0m

              For example, if your [4mfamily[24m is [1mHelvetica[22m, entering
                     [1m.FT B[0m
              will give you the [4mHelvetica[24m [4mbold[24m  [4mfont[24m.   If  your  [4mfamily[24m  were
              [1mPalatino[22m, you’d get the [4mPalatino[24m [4mbold[24m [4mfont[24m.

              [1mMom  [22mconsiderably extends the range of arguments you can pass to
              [1m.FT[22m, making it more convenient to add and access fonts  of  dif‐
              fering weights and shapes within the same family.

              Have  a  look  here for a list of the weight/style arguments [4mmom[0m
              allows.  Be aware, though, that you must have  the  fonts,  cor‐
              rectly installed and named, in order to use the arguments.  (See
              [4mAdding[24m [4mfonts[24m [4mto[24m [4mgroff[24m for instructions and information.)  Please
              also  read  the  [4mADDITIONAL[24m [4mNOTE[24m found in the description of the
              [1m.FAMILY [22mmacro.

              How [4mmom[24m reacts to an invalid argument to [1m.FT  [22mdepends  on  which
              version  of [4mgroff[24m you’re using.  If your [4mgroff[24m version is 1.19.2
              or later, [4mmom[24m will issue a warning and, depending on how  you’ve
              set  up  the fallback font, either continue processing using the
              fallback font, or abort (allowing you to correct  the  problem).
              In  earlier versions, [4mmom[24m will silently continue processing, us‐
              ing either the fallback font or the font that was in effect pri‐
              or to the invalid [1m.FT [22mcall.

              [1m.FT [22mwill also accept, as an argument, a  full  [4mfamily[24m  and  [4mfont[0m
              [4mname[24m.

              For example,
                     [1m.FT HB[0m
              will set subsequent type in [4mHelvetica[24m [4mBold[24m.

              However,  I  strongly recommend keeping [4mfamily[24m and [4mfont[24m separate
              except where doing so is genuinely inconvenient.

              For inline control of [4mfonts[24m, see [4mInline[24m [4mEscapes[24m, font control.

       [1m.HI [ [4m[22m<measure>[24m [1m][0m
              Hanging indent — the optional argument requires a unit  of  mea‐
              sure.

              A hanging indent looks like this:
                     The thousand injuries of Fortunato I had borne as best I
                       could, but when he ventured upon insult, I vowed
                       revenge.  You who so well know the nature of my soul
                       will not suppose, however, that I gave utterance to a
                       threat, at length I would be avenged...
              The first line of text [4mhangs[24m outside the [4mleft[24m [4mmargin[24m.

              In  order to use [4mhanging[24m [4mindents[24m, you must first have a [4mleft[24m [4min‐[0m
              [4mdent[24m active (set with either [1m.IL [22mor [1m.IB[22m).   [1mMom  [22mwill  not  hang
              text  outside  the [4mleft[24m [4mmargin[24m [4mset[24m with [1m.L_MARGIN [22mor outside the
              [4mleft[24m [4mmargin[24m of a [4mtab[24m.

              The first time you invoke [1m.HI[22m, you must give it a  [1mmeasure[22m.   If
              you  want the first line of a paragraph to [4mhang[24m [4mby[24m, say, [4m1[24m [4mpica[24m,
              do
                     [1m.IL 1P[0m
                     [1m.HI 1P[0m
              Subsequent invocations of [1m.HI [22mdo not require  you  to  supply  a
              [4mmeasure[24m; [4mmom[24m keeps track of the last measure you gave it.

              Generally  speaking,  you should invoke [1m.HI [22mimmediately prior to
              the line you want hung (i.e.  without  any  intervening  control
              lines).   And  because  [4mhanging[24m  [4mindents[24m  affect  only one line,
              there’s no need to turn them off.

              [4mIMPORTANT:[24m Unlike [1mIL[22m, [1mIR [22mand [1mIB[22m, measures given to [1m.HI  [22mare  NOT
              additive.   Each  time you pass a measure to [1m.HI[22m, the measure is
              treated literally.  [4mRecipe:[24m A numbered list  using  [4mhanging[24m  [4min‐[0m
              [4mdents[0m

              [4mNote:[24m  [4mmom[24m  has macros for setting lists.  This recipe exists to
              demonstrate the use of [4mhanging[24m [4mindents[24m only.
                     .PAGE 8.5i 11i 1i 1i 1i 1i
                     .FAMILY  T
                     .FT      R
                     .PT_SIZE 12
                     .LS      14
                     .JUSTIFY
                     .KERN
                     .SS 0
                     .IL \w'\0\0.'
                     .HI \w'\0\0.'
                     1.\0The most important point to be considered is whether
                     the answer to the meaning of Life, the Universe, and
                     Everything really is 42.  We have no one's word on the
                     subject except Mr. Adams's.
                     .HI
                     2.\0If the answer to the meaning of Life, the Universe,
                     and Everything is indeed 42, what impact does this have on
                     the politics of representation?  42 is, after all not a
                     prime number.  Are we to infer that prime numbers don't
                     deserve equal rights and equal access in the universe?
                     .HI
                     3.\0If 42 is deemed non‐exclusionary, how do we present
                     it as the answer and, at the same time, forestall debate
                     on its exclusionary implications?

              First, we invoke a left indent with a measure equal to the width
              of 2 figures spaces plus a period (using the \w inline  escape).
              At  this  point, the left indent is active; text afterward would
              normally be indented.  However, we invoke a  hanging  indent  of
              exactly  the  same  width, which hangs the first line (and first
              line only!) to the left of the indent by the same  distance  (in
              this case, that means “out to the left margin”).  Because we be‐
              gin  the first line with a number, a period, and a figure space,
              the actual text ([4mThe[24m [4mmost[24m [4mimportant[24m [4mpoint...[24m) starts at  exactly
              the same spot as the indented lines that follow.

              Notice  that  subsequent invocations of [1m.HI [22mdon’t require a [4mmea‐[0m
              [4msure[24m to be given.

              Paste the example above into a file and preview it with
                     [1mpdfmom filename.mom | ps2pdf - filename.pdf[0m
              to see hanging indents in action.

       [1m.IB [ [4m[22m<left[24m [4mmeasure>[24m [4m<right[24m [4mmeasure>[24m [1m][0m
              Indent both — the optional argument requires a unit of measure

              [1m.IB [22mallows you to set or invoke a left and a right indent at the
              same time.

              At its first invocation, you must supply a measure for both  in‐
              dents;  at subsequent invocations when you wish to supply a mea‐
              sure, both must be given again.  As with [1m.IL [22mand [1m.IR[22m,  the  mea‐
              sures  are  added  to the values previously passed to the macro.
              Hence, if you wish to change just one of the  values,  you  must
              give an argument of zero to the other.

              [4mA[24m  [4mword[24m  [4mof[24m [4madvice:[24m If you need to manipulate left and right in‐
              dents separately, use a combination of [1m.IL [22mand  [1m.IR  [22minstead  of
              [1m.IB[22m.  You’ll save yourself a lot of grief.

              A  [4mminus[24m [4msign[24m may be prepended to the arguments to subtract from
              their current values.  The \w inline escape may be used to spec‐
              ify text‐dependent measures, in which case no unit of measure is
              required.  For example,
                     [1m.IB \w'margarine' \w'jello'[0m
              left indents text by the width of the word [4mmargarine[24m  and  right
              indents by the width of [4mjello[24m.

              Like  [1m.IL  [22mand [1m.IR[22m, [1m.IB [22mwith no argument indents by its last ac‐
              tive values.  See the brief explanation of how mom  handles  in‐
              dents for more details.

              [4mNote:[24m  Calling  a  [4mtab[24m (with [1m.TAB <n>[22m) automatically cancels any
              active indents.

              [4mAdditional[24m [4mnote:[24m Invoking [1m.IB [22mautomatically turns  off  [1m.IL  [22mand
              [1m.IR[22m.

       [1m.IL [ [4m[22m<measure>[24m [1m][0m
              Indent left — the optional argument requires a unit of measure

              [1m.IL  [22mindents text from the left margin of the page, or if you’re
              in a [4mtab[24m, from the left edge of the [4mtab[24m.  Once  [4mIL[24m  is  on,  the
              [4mleft[24m  [4mindent[24m  is  applied  uniformly to every subsequent line of
              text, even if you change the line length.

              The first time you invoke [1m.IL[22m, you must give it a measure.  Sub‐
              sequent invocations with a measure add to the previous  measure.
              A  minus  sign may be prepended to the argument to subtract from
              the current measure.  The [1m\w [22minline escape may be used to speci‐
              fy a text‐dependent measure, in which case no unit of measure is
              required.  For example,
                     [1m.IL \w'margarine'[0m
              indents text by the width of the word [4mmargarine[24m.

              With no argument, [1m.IL [22mindents by its last active value.  See the
              brief explanation of how [4mmom[24m handles indents for more details.

              [4mNote:[24m Calling a [4mtab[24m (with [1m.TAB <n>[22m)  automatically  cancels  any
              active indents.

              [4mAdditional[24m [4mnote:[24m Invoking [1m.IL [22mautomatically turns off [1mIB[22m.

       [1m.IQ [ [4m[22m<measure>[24m [1m][0m
              IQ — quit any/all indents

              [4mIMPORTANT[24m  [4mNOTE:[24m The original macro for quitting all indents was
              [1m.IX[22m.  This usage has been deprecated in favour of [1mIQ[22m.  [1m.IX  [22mwill
              continue  to  behave  as before, but [4mmom[24m will issue a warning to
              [4mstderr[24m indicating that you should update your documents.

              As a consequence of this change, [1m.ILX[22m, [1m.IRX [22mand [1m.IBX [22mmay now al‐
              so be invoked as [1m.ILQ[22m, [1m.IRQ [22mand [1m.IBQ[22m.  Both  forms  are  accept‐
              able.

              Without  an  argument, the macros to quit indents merely restore
              your original margins and line length.  The measures  stored  in
              the  indent  macros  themselves  are  saved so you can call them
              again without having to supply a measure.

              If you pass these macros the optional argument [1mCLEAR[22m,  they  not
              only restore your original left margin and line length, but also
              clear any values associated with a particular indent style.  The
              next time you need an indent of the same style, you have to sup‐
              ply a measure again.

              [1m.IQ CLEAR[22m, as you’d suspect, quits and clears the values for all
              indent styles at once.

       [1m.IR [ [4m[22m<measure>[24m [1m][0m
              Indent right — the optional argument requires a unit of measure

              [1m.IR [22mindents text from the [4mright[24m [4mmargin[24m of the page, or if you’re
              in a [4mtab[24m, from the end of the [4mtab[24m.

              The first time you invoke [1m.IR[22m, you must give it a measure.  Sub‐
              sequent  invocations  with  a measure add to the previous indent
              measure.  A [4mminus[24m [4msign[24m may be prepended to the argument to  sub‐
              tract from the current indent measure.  The \w inline escape may
              be  used  to  specify a text‐dependent measure, in which case no
              [4munit[24m [4mof[24m [4mmeasure[24m is required.  For example,
                     [1m.IR \w'jello'[0m
              indents text by the width of the word [4mjello[24m.

              With no argument, [1m.IR [22mindents by its last active value.  See the
              brief explanation of how [4mmom[24m handles indents for more details.

              [4mNote:[24m Calling a [4mtab[24m (with [1m.TAB <n>[22m)  automatically  cancels  any
              active indents.

              [4mAdditional[24m [4mnote:[24m Invoking [1m.IR [22mautomatically turns off [1mIB[22m.

       [1m.L_MARGIN [4m[22m<left[24m [4mmargin>[0m
              Left Margin

              L_MARGIN  establishes  the  distance  from  the left edge of the
              printer sheet at which you want your type to start.  It  may  be
              used  any time, and remains in effect until you enter a new val‐
              ue.

              Left indents and tabs are calculated from the value you pass  to
              [1m.L_MARGIN[22m,  hence  it’s  always  a good idea to invoke it before
              starting any serious typesetting.  A  unit  of  measure  is  re‐
              quired.   Decimal  fractions are allowed.  Therefore, to set the
              left margin at 3 picas (1/2 inch), you’d enter either
                     [1m.L_MARGIN 3P[0m
              or
                     [1m.L_MARGIN .5i[0m

              If you use the macros [1m.PAGE[22m, [1m.PAGEWIDTH [22mor [1m.PAPER [22mwithout invok‐
              ing [1m.L_MARGIN [22m(either before or  afterward),  [4mmom[24m  automatically
              sets [1m.L_MARGIN [22mto [4m1[24m [4minch[24m.

              Note:  [1m.L_MARGIN  [22mbehaves in a special way when you’re using the
              document processing macros.

       [1m.MCO   [22mBegin multi‐column setting.

              [1m.MCO [22m([4mMulti‐Column[24m [4mOn[24m) is the [4mmacro[24m you use to begin  [4mmulti‐col‐[0m
              [4mumn[24m  [4msetting[24m.   It marks the current baseline as the top of your
              columns, for use later  with  [1m.MCR[22m.   See  the  introduction  to
              columns  for an explanation of [4mmulti‐columns[24m and some sample in‐
              put.

              [4mNote:[24m Do not confuse [1m.MCO [22mwith the [1m.COLUMNS [22mmacro in  the  docu‐
              ment processing macros.

       [1m.MCR   [22mOnce  you’ve  turned  [4mmulti‐columns[24m on (with [1m.MCO[22m), [1m.MCR[22m, at any
              time, returns you to the [4mtop[24m [4mof[24m [4myour[24m [4mcolumns[24m.

       [1m.MCX [ [4m[22m<distance[24m [4mto[24m [4madvance[24m [4mbelow[24m [4mlongest[24m [4mcolumn>[24m [1m][0m
              Optional argument requires a unit of measure.

              Exit multi‐columns.

              [1m.MCX [22mtakes you out of any [4mtab[24m you were in (by silently  invoking
              [1m.TQ[22m) and advances to the bottom of the longest column.

              Without an argument, [1m.MCX [22madvances [4m1[24m [4mlinespace[24m below the longest
              column.

              Linespace, in this instance, is the leading in effect at the mo‐
              ment [1m.MCX [22mis invoked.

              If you pass the [4m<distance>[24m argument to [1m.MCX[22m, it advances [4m1[24m [4mline‐[0m
              [4mspace[24m  below  the  longest  column (see above) [4mPLUS[24m the distance
              specified by the argument.  The argument requires a unit of mea‐
              sure; therefore, to advance an extra 6 points below  where  [1m.MCX[0m
              would normally place you, you’d enter
                     [1m.MCX 6p[0m

              [4mNote:[24m  If you wish to advance a precise distance below the base‐
              line of the longest column, use [1m.MCX [22mwith an argument of [1m0  [22m(ze‐
              ro;  no  [4munit[24m  [4mof[24m [4mmeasure[24m required) in conjunction with the [1m.ALD[0m
              macro, like this:
                     [1m.MCX 0[0m
                     [1m.ALD 24p[0m
              The above advances to precisely [4m24[24m [4mpoints[24m below the baseline  of
              the longest column.

       [1m.NEWPAGE[0m

              Whenever  you  want to start a new page, use [1m.NEWPAGE[22m, by itself
              with no argument.  [1mMom [22mwill finish  up  processing  the  current
              page  and  move  you to the top of a new one (subject to the top
              margin set with [1m.T_MARGIN[22m).

       [1m.PAGE [4m[22m<width>[24m [1m[ [4m[22m<length>[24m [1m[ [4m[22m<lm>[24m [1m[ [4m[22m<rm>[24m [1m[ [4m[22m<tm>[24m [1m[ [4m[22m<bm>[24m [1m] ] ] ] ][0m

              All arguments require a unit of measure

              [4mIMPORTANT:[24m If you’re using the document processing macros, [1m.PAGE[0m
              must come after [1m.START[22m.  Otherwise, it should go at the top of a
              document, prior to any text.  And remember,  when  you’re  using
              the  document  processing  macros,  top margin and bottom margin
              mean something slightly different than when  you’re  using  just
              the  typesetting  macros (see Top and bottom margins in document
              processing).

              [1m.PAGE [22mlets you establish paper dimensions and page margins  with
              a  single macro.  The only required argument is page width.  The
              rest are optional, but they must appear in order and  you  can’t
              skip  over  any.   [4m<lm>[24m,  [4m<rm>[24m, [4m<tm>[24m and [4m<bm>[24m refer to the left,
              right, top and bottom margins respectively.

              Assuming your page dimensions are 11 inches by  17  inches,  and
              that’s all you want to set, enter
                     [1m.PAGE 11i 17i[0m
              If you want to set the left margin as well, say, at 1 inch, [1mPAGE[0m
              would look like this:
                     [1m.PAGE 11i 17i 1i[0m

              Now  suppose  you also want to set the top margin, say, at 1–1/2
              inches.  [4m<tm>[24m comes after [4m<rm>[24m in the  optional  arguments,  but
              you can’t skip over any arguments, therefore to set the top mar‐
              gin,  you  must also give a right margin.  The [1m.PAGE [22mmacro would
              look like this:
                     .PAGE 11i 17i 1i 1i 1.5i
                                      |   |
                     required right---+   +---top margin
                             margin

              Clearly, [1m.PAGE [22mis best used when you want a  convenient  way  to
              tell  [4mmom[24m  just  the dimensions of your printer sheet (width and
              length), or when you want to tell her everything about the  page
              (dimensions and all the margins), for example
                     [1m.PAGE 8.5i 11i 45p 45p 45p 45p[0m
              This  sets  up  an  8½ by 11 inch page with margins of 45 points
              (5/8‐inch) all around.

              Additionally, if you invoke [1m.PAGE [22mwith a  top  margin  argument,
              any macros you invoke after [1m.PAGE [22mwill almost certainly move the
              baseline  of  the  first line of text down by one linespace.  To
              compensate, do
                     [1m.RLD 1v[0m
              immediately before entering any text, or, if it’s feasible, make
              [1m.PAGE [22mthe last macro you invoke prior to entering text.

              Please read the [4mImportant[24m [4mnote[24m on page dimensions and  papersize
              for information on ensuring [4mgroff[24m respects your [1m.PAGE [22mdimensions
              and margins.

       [1m.PAGELENGTH [4m[22m<length[24m [4mof[24m [4mprinter[24m [4msheet>[0m
              tells  [4mmom[24m  how  long your printer sheet is.  It works just like
              [1m.PAGEWIDTH[22m.

              Therefore, to tell [4mmom[24m your printer sheet is 11 inches long, you
              enter
                     [1m.PAGELENGTH 11i[0m
              Please read the important note on page dimensions and  papersize
              for information on ensuring [4mgroff[24m respects your [4mPAGELENGTH[24m.

       [1m.PAGEWIDTH [4m[22m<width[24m [4mof[24m [4mprinter[24m [4msheet>[0m

              The argument to [1m.PAGEWIDTH [22mis the width of your printer sheet.

              [1m.PAGEWIDTH  [22mrequires  a  unit of measure.  Decimal fractions are
              allowed.  Hence, to tell [4mmom[24m that  the  width  of  your  printer
              sheet is 8½ inches, you enter
                     .PAGEWIDTH 8.5i

              Please  read the Important note on page dimensions and papersize
              for information on ensuring [4mgroff[24m respects your [4mPAGEWIDTH[24m.

       [1m.PAPER [4m[22m<paper[24m [4mtype>[0m
              provides a convenient way to set the page  dimensions  for  some
              common  printer  sheet  sizes.  The argument [4m<paper[24m [4mtype>[24m can be
              one of: [1mLETTER[22m, [1mLEGAL[22m, [1mSTATEMENT[22m, [1mTABLOID[22m, [1mLEDGER[22m, [1mFOLIO[22m,  [1mQUAR‐[0m
              [1mTO[22m, [1mEXECUTIVE[22m, [1m10x14[22m, [1mA3[22m, [1mA4[22m, [1mA5[22m, [1mB4[22m, [1mB5[22m.

       [1m.PRINTSTYLE[0m

       [1m.PT_SIZE [4m[22m<size[24m [4mof[24m [4mtype[24m [4min[24m [4mpoints>[0m
              Point size of type, does not require a [4munit[24m [4mof[24m [4mmeasure[24m.

              [1m.PT_SIZE  [22m([4mPoint[24m  [4mSize[24m)  takes one argument: the [4msize[24m [4mof[24m [4mtype[24m in
              [4mpoints[24m.  Unlike most other macros that  establish  the  [4msize[24m  or
              [4mmeasure[24m  of something, [1m.PT_SIZE [22mdoes not require that you supply
              a [4munit[24m [4mof[24m [4mmeasure[24m since it’s a near  universal  convention  that
              [4mtype[24m  [4msize[24m is measured in [4mpoints[24m.  Therefore, to change the [4mtype[0m
              [4msize[24m to, say, [4m11[24m [4mpoints[24m, enter
                     [1m.PT_SIZE 11[0m
              [4mPoint[24m [4msizes[24m may be [4mfractional[24m (e.g., [4m10.25[24m or [4m12.5[24m).

              You can prepend a [4mplus[24m or  a  [4mminus[24m  [4msign[24m  to  the  argument  to
              [1m.PT_SIZE[22m, in which case the [4mpoint[24m [4msize[24m will be changed by [4m+[24m or [4m-[0m
              the  original  value.  For example, if the [4mpoint[24m [4msize[24m is [4m12[24m, and
              you want [4m14[24m, you can do
                     [1m.PT_SIZE +2[0m
              then later reset it to [4m12[24m with
                     [1m.PT_SIZE -2[0m
              The [4msize[24m [4mof[24m [4mtype[24m can also be changed inline.

              [4mNote:[24m It is unfortunate that the [1mpic  [22mpreprocessor  has  already
              taken the name, PS, and thus [4mmom[24m’s macro for setting [4mpoint[24m [4msizes[0m
              can’t  use it.  However, if you aren’t using [1mpic[22m, you might want
              to alias [1m.PT_SIZE [22mas [1m.PS[22m, since there’d be no conflict.  For ex‐
              ample
                     [1m.ALIAS PS PT_SIZE[0m
              would allow you to set [4mpoint[24m [4msizes[24m with [1m.PS[22m.

       [1m.R_MARGIN [4m[22m<right[24m [4mmargin>[0m
              Right Margin

              Requires a unit of measure.

              IMPORTANT:  [1m.R_MARGIN[22m,  if  used,  must   come   after   [1m.PAPER[22m,
              [1m.PAGEWIDTH[22m,  [1m.L_MARGIN[22m,  and/or  [1m.PAGE  [22m(if a right margin isn’t
              given to PAGE).  The reason is that  [1m.R_MARGIN  [22mcalculates  line
              length from the overall page dimensions and the left margin.

              Obviously,  it can’t make the calculation if it doesn’t know the
              page width and the left margin.

              [1m.R_MARGIN [22mestablishes the amount of space you want  between  the
              end  of  typeset  lines  and  the right hand edge of the printer
              sheet.  In other words, it sets the line length.  [1m.R_MARGIN  [22mre‐
              quires a unit of measure.  Decimal fractions are allowed.

              The  line  length  macro (LL) can be used in place of [1m.R_MARGIN[22m.
              In either case, the last one invoked sets the line length.   The
              choice of which to use is up to you.  In some instances, you may
              find  it  easier to think of a section of type as having a right
              margin.  In others, giving a line length may make more sense.

              For example, if you’re setting a page of type  you  know  should
              have  6‐pica  margins  left and right, it makes sense to enter a
              left and right margin, like this:
                     [1m.L_MARGIN 6P[0m
                     [1m.R_MARGIN 6P[0m

              That way, you don’t have to worry  about  calculating  the  line
              length.   On  the  other hand, if you know the line length for a
              patch of type should be 17 picas and 3 points, entering the line
              length with LL is much easier than calculating the right margin,
              e.g.,
                     [1m.LL 17P+3p[0m

              If you use the macros [1m.PAGE[22m, [1m.PAGEWIDTH [22mor [1mPAPER [22mwithout  invok‐
              ing  [1m.R_MARGIN  [22mafterward, [4mmom[24m automatically sets [1m.R_MARGIN [22mto [4m1[0m
              [4minch[24m.  If you set a line length after these macros  (with  [1m.LL[22m),
              the  line length calculated by [1m.R_MARGIN [22mis, of course, overrid‐
              den.

              Note: [1m.R_MARGIN [22mbehaves in a special way when you’re  using  the
              document processing macros.

       [1m.ST [4m[22m<tab[24m [4mnumber>[24m [1mL | R | C | J [ QUAD ][0m

              After  [4mstring[24m  [4mtabs[24m  have  been marked off on an input line (see
              [1m\*[ST]...\*[STX][22m), you need to [4mset[24m them by giving them a  direc‐
              tion and, optionally, the [1mQUAD [22margument.

              In this respect, [1m.ST [22mis like [1m.TAB_SET [22mexcept that you don’t have
              to  give  [1m.ST  [22man  indent or a line length (that’s already taken
              care of, inline, by [1m\*[ST]...\*[STX][22m).

              If you want string [4mtab[24m [4m1[24m to be [1mleft[22m, enter
                     [1m.ST 1 L[0m
              If you want it to be [4mleft[24m and [4mfilled[24m, enter
                     [1m.ST 1 L QUAD[0m
              If you want it to be justified, enter
                     [1m.ST 1 J[0m

       [1m.TAB [4m[22m<tab[24m [4mnumber>[0m
              After [4mtabs[24m have been defined (either with [1m.TAB_SET [22mor [1m.ST[22m), [1m.TAB[0m
              moves to whatever [4mtab[24m [4mnumber[24m you pass it as an argument.

              For example,
                     [1m.TAB 3[0m
              moves you to [4mtab[24m [4m3[24m.

              Note: [1m.TAB [22mbreaks the line preceding it  and  advances  1  line‐
              space.  Hence,
                     [1m.TAB 1[0m
                     [1mA line of text in tab 1.[0m
                     [1m.TAB 2[0m
                     [1mA line of text in tab 2.[0m
              produces, on output
                     [1mA line of text in tab 1.[0m
                                                  [1mA line of text in tab 2.[0m

              If  you  want the tabs to line up, use [1m.TN [22m(“Tab Next”) or, more
              conveniently, the inline escape sequence [1m\*[TB+][22m:
                     [1m.TAB [22m1
                     A line of text in tab 1.\*[TB+]
                     A line of text in tab 2.
              which produces
                     [1mA line of text in tab 1.   A line of text in tab 2.[0m

              If the text in your tabs runs to several lines, and you want the
              first lines of each tab to align, you must use the  multi‐column
              macros.

              [4mAdditional[24m  [4mnote:[24m  Any  indents in effect prior to calling a tab
              are automatically turned off by [1mTAB[22m.  If you were  happily  zip‐
              ping  down the page with a left indent of [4m2[24m [4mpicas[24m turned on, and
              you call a [4mtab[24m whose indent from the left  margin  is  [4m6[24m  [4mpicas[24m,
              your  new distance from the [4mleft[24m [4mmargin[24m will be [4m6[24m [4mpicas[24m, not I 6
              picas plus the 2 pica indent.

              [4mTabs[24m are not by nature columnar, which is to  say  that  if  the
              text  inside  a  [4mtab[24m  runs to several lines, calling another [4mtab[0m
              does not automatically move to the baseline of the first line in
              the [4mprevious[24m [4mtab[24m.  To demonstrate:
                     TAB 1
                     Carrots
                     Potatoes
                     Broccoli
                     .TAB 2
                     $1.99/5 lbs
                     $0.25/lb
                     $0.99/bunch
              produces, on output
                     Carrots
                     Potatoes
                     Broccoli
                                 $1.99/5 lbs
                                 $0.25/lb
                                 $0.99/bunch

       [1m.TB [4m[22m<tab[24m [4mnumber>[0m
              Alias to [1m.TAB[0m

       [1m.TI [ [4m[22m<measure>[24m [1m][0m
              Temporary left indent — the optional argument requires a [4munit[24m [4mof[0m
              [4mmeasure[0m

              A temporary indent is one that applies only to the first line of
              text that comes after it.  Its chief use is indenting the  first
              line  of paragraphs.  ([1mMom’s .PP [22mmacro, for example, uses a [4mtem‐[0m
              [4mporary[24m [4mindent[24m.)

              The first time you invoke [1m.TI[22m, you must give it a  measure.   If
              you want to [4mindent[24m the first line of a paragraph by, say, 2 ems,
              do
                     [1m.TI 2m[0m

              Subsequent  invocations  of  [1m.TI  [22mdo not require you to supply a
              measure; [4mmom[24m keeps track of the last measure you gave it.

              Because [4mtemporary[24m [4mindents[24m are temporary, there’s no need to turn
              them off.

              [4mIMPORTANT:[24m Unlike [1m.IL[22m, [1m.IR [22mand [1mIB[22m, measures given to [1m.TI [22mare NOT
              additive.  In the following example, the second [1m".TI 2P" [22mis  ex‐
              actly [4m2[24m [4mpicas[24m.
                     [1m.TI 1P[0m
                     [1mThe beginning of a paragraph...[0m
                     [1m.TI 2P[0m
                     [1mThe beginning of another paragraph...[0m

       [1m.TN    [22mTab Next

              Inline escape [1m\*[TB+][0m

              [1mTN  [22mmoves  over  to  the  [4mnext[24m [4mtab[24m in numeric sequence ([4mtab[24m [4mn+1[24m)
              without advancing on the page.  See the [4mNOTE[24m in the  description
              of the [1m.TAB [22mmacro for an example of how [1mTN [22mworks.

              In  [4mtabs[24m that aren’t given the [1mQUAD [22margument when they’re set up
              with [1m.TAB_SET [22mor [1mST[22m, you must terminate the line  preceding  [1m.TN[0m
              with the [1m\c [22minline escape sequence.  Conversely, if you did give
              a [1mQUAD [22margument to [1m.TAB_SET [22mor [1mST[22m, the [1m\c must not be used.[0m

              If you find remembering whether to put in the [1m\c [22mbothersome, you
              may prefer to use the inline escape alternative to [1m.TN[22m, [1m\*[TB+][22m,
              which works consistently regardless of the fill mode.

              [4mNote:[24m You must put text in the input line immediately after [1m.TN[22m.
              Stacking of [1m.TN[22m’s is not allowed.  In other words, you cannot do
                     .TAB 1
                     Some text\c
                     .TN
                     Some more text\c
                     .TN
                     .TN
                     Yet more text
              The above example, assuming [4mtabs[24m numbered from [4m1[24m to [4m4[24m, should be
              entered
                     .TAB 1
                     Some text\c
                     .TN
                     Some more text\c
                     .TN
                     \&\c
                     .TN
                     Yet more text
              \& is a zero‐width, non‐printing character that [4mgroff[24m recognizes
              as  valid input, hence meets the requirement for input text fol‐
              lowing [1m.TN[22m.

       [1m.TQ    TQ [22mtakes you out of whatever [4mtab[24m you were in, advances  [4m1[24m  [4mline‐[0m
              [4mspace[24m, and restores the [4mleft[24m [4mmargin[24m, [4mline[24m [4mlength[24m, [4mquad[24m [4mdirection[0m
              and [4mfill[24m [4mmode[24m that were in effect prior to invoking any [4mtabs[24m.

       [1m.T_MARGIN [4m[22m<top[24m [4mmargin>[0m
              Top margin

              Requires a unit of measure

              [1m.T_MARGIN  [22mestablishes  the distance from the top of the printer
              sheet at which you want your type to start.  It requires a  unit
              of  measure,  and  decimal  fractions are allowed.  To set a top
              margin of 2½ centimetres, you’d enter
                     [1m.T_MARGIN 2.5c[0m
              [1m.T_MARGIN [22mcalculates the vertical position of the first line  of
              type  on a page by treating the top edge of the printer sheet as
              a baseline.  Therefore,
                     [1m.T_MARGIN 1.5i[0m
              puts the baseline of the first line of type  1½  inches  beneath
              the top of the page.

              Note:  [1m.T_MARGIN  [22mmeans something slightly different when you’re
              using the document processing macros.  See Top and  bottom  mar‐
              gins in document processing for an explanation.

              IMPORTANT:  [1m.T_MARGIN  [22mdoes  two  things: it establishes the top
              margin for pages that come after it and it moves to  that  posi‐
              tion  on  the current page.  Therefore, [1m.T_MARGIN [22mshould only be
              used at the top of a file (prior to entering text) or after NEW‐
              PAGE, like this:
                     [1m.NEWPAGE[0m
                     [1m.T_MARGIN 6P[0m
                     [4m<text>[0m

[1mAuthors[0m
       [4mmom[24m was written by Peter Schaffter ⟨peter@schaffter.ca⟩.   PDF  support
       was  provided by Deri James ⟨deri@chuzzlewit.myzen.co.uk⟩.  This manual
       page was written by Bernd Warken.

[1mSee also[0m
       [4m/usr/share/doc/groff-1.23.0/html/mom/toc.html[0m
              entry point to the HTML documentation

       ⟨http://www.schaffter.ca/mom/momdoc/toc.html⟩
              HTML documentation online

       ⟨http://www.schaffter.ca/mom/⟩
              the [4mmom[24m macros homepage

       [4mGroff:[24m [4mThe[24m [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher  and  Werner
       Lemberg,  is the primary [4mgroff[24m manual.  You can browse it interactively
       with “info groff”.

       [4mpdfmom[24m(1), [4mgroff[24m(1), [4mtroff[24m(1)

groff 1.23.0                      5 July 2023                     [4mgroff_mom[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_ms[24m(7)            Miscellaneous Information Manual            [4mgroff_ms[24m(7)

[1mName[0m
       groff_ms - GNU [4mroff[24m manuscript macro package for formatting documents

[1mSynopsis[0m
       [1mgroff -ms [22m[[4moption[24m ...] [[4mfile[24m ...]
       [1mgroff -m ms [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       The GNU implementation of the [4mms[24m macro package is  part  of  the  [4mgroff[0m
       document  formatting system.  The [4mms[24m package is suitable for the compo‐
       sition of letters, memoranda, reports, and books.

       These [4mgroff[24m macros support cover page and table of contents generation,
       automatically numbered headings, several paragraph styles, a variety of
       text styling options, footnotes, and  multi‐column  page  layouts.   [4mms[0m
       supports the [4mtbl[24m(1), [4meqn[24m(1), [4mpic[24m(1), and [4mrefer[24m(1) preprocessors for in‐
       clusion  of  tables, mathematical equations, diagrams, and standardized
       bibliographic citations.

       This implementation is mostly compatible with the documented  interface
       and  behavior  of  AT&T Unix Version 7 [4mms[24m.  Many extensions from 4.2BSD
       (Berkeley) and Tenth Edition Research Unix have been recreated.

[1mUsage[0m
       The [4mms[24m macro package expects a certain amount  of  structure:  a  well‐
       formed  document  contains  at  least one paragraphing or heading macro
       call.  To compose a simple document from scratch, begin it  by  calling
       [1m.LP [22mor [1m.PP[22m.  Longer documents have a structure as follows.

       [1mDocument type[0m
              Calling  the [1mRP [22mmacro at the beginning of your document puts the
              document description (see below) on a cover page.  Otherwise, [4mms[0m
              places this information on the first page, followed  immediately
              by  the body text.  Some document types found in other [4mms[24m imple‐
              mentations are specific to AT&T or Berkeley, and  are  not  sup‐
              ported in [4mgroff[24m [4mms[24m.

       [1mFormat and layout[0m
              By  setting  registers and strings, you can configure your docu‐
              ment’s typeface, margins,  spacing,  headers  and  footers,  and
              footnote  arrangement.   See  subsection  “Document control set‐
              tings” below.

       [1mDocument description[0m
              A document description consists of any of: a title, one or  more
              authors’  names  and affiliated institutions, an abstract, and a
              date or other identifier.  See subsection “Document  description
              macros” below.

       [1mBody text[0m
              The  main  matter  of  your document follows its description (if
              any).  [4mms[24m supports highly structured text  consisting  of  para‐
              graphs  interspersed  with  multi‐level headings (chapters, sec‐
              tions, subsections, and so forth) and augmented by lists,  foot‐
              notes,  tables,  diagrams, and similar material.  The preponder‐
              ance of subsections below covers these matters.

       [1mTable of contents[0m
              Macros enable the collection of entries for a table of  contents
              (or index) as the material they discuss appears in the document.
              You  then  call a macro to emit the table of contents at the end
              of your document.  The table of contents must necessarily follow
              the rest of the text since GNU [4mtroff[24m is a single‐pass formatter;
              it thus cannot determine the page number of a  division  of  the
              text  until it has been set and output.  Since [4mms[24m output was de‐
              signed for the production of hard copy, the  traditional  proce‐
              dure  was to manually relocate the pages containing the table of
              contents between the cover page and the body text.  Today,  page
              resequencing is more often done in the digital domain.  An index
              works similarly, but because it typically needs to be sorted af‐
              ter collection, its preparation requires separate processing.

   [1mDocument control settings[0m
       The  following tables list the document control registers, strings, and
       special characters.  For any parameter whose default is unsatisfactory,
       define it before calling any [4mms[24m macro other than [1mRP[22m.

                                   [1mMargin settings[0m
       [1mParameter            Definition               Effective       Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[PO]      Page offset (left margin)       next page        1i (0)
       \n[LL]      Line length                     next paragraph   6.5i (65n)
       \n[LT]      Title line length               next paragraph   6.5i (65n)
       \n[HM]      Top (header) margin             next page        1i
       \n[FM]      Bottom (footer) margin          next page        1i
       ────────────────────────────────────────────────────────────────────────

                              [1mTitles (headers, footers)[0m
       [1mParameter               Definition                 Effective    Default[0m
       ────────────────────────────────────────────────────────────────────────
       \*[LH]      Left header text                      next header   [4mempty[0m
       \*[CH]      Center header text                    next header   -\n[%]-
       \*[RH]      Right header text                     next header   [4mempty[0m
       \*[LF]      Left footer text                      next footer   [4mempty[0m
       \*[CF]      Center footer text                    next footer   [4mempty[0m
       \*[RF]      Right footer text                     next footer   [4mempty[0m
       ────────────────────────────────────────────────────────────────────────

                                    [1mText settings[0m
       [1mParameter              Definition                Effective      Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[PS]      Point size                         next paragraph   10p
       \n[VS]      Vertical spacing (leading)         next paragraph   12p
       \n[HY]      Hyphenation mode                   next paragraph   6
       \*[FAM]     Font family                        next paragraph   T
       ────────────────────────────────────────────────────────────────────────

                                 [1mParagraph settings[0m
        [1mParameter             Definition              Effective       Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[PI]        Indentation                    next paragraph   5n
       \n[PD]        Paragraph distance (spacing)   next paragraph   0.3v (1v)
       \n[QI]        Quotation indentation          next paragraph   5n
       \n[PORPHANS]  # of initial lines kept        next paragraph   1
       ────────────────────────────────────────────────────────────────────────

                                  [1mHeading settings[0m
        [1mParameter              Definition             Effective      Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[PSINCR]     Point size increment           next heading   1p
       \n[GROWPS]     Size increase depth limit      next heading   0
       \n[HORPHANS]   # of following lines kept      next heading   1
       \*[SN-STYLE]   Numbering style (alias)        next heading   \*[SN-DOT]
       ────────────────────────────────────────────────────────────────────────

       [1m\*[SN-STYLE] [22mcan alternatively be made an alias of  [1m\*[SN-NO-DOT]  [22mwith
       the [1mals [22mrequest.

                                  [1mFootnote settings[0m
       [1mParameter             Definition               Effective      Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[FI]      Indentation                      next footnote   2n
       \n[FF]      Format                           next footnote   0
       \n[FPS]     Point size                       next footnote   \n[PS]-2p
       \n[FVS]     Vertical spacing (leading)       next footnote   \n[FPS]+2p
       \n[FPD]     Paragraph distance (spacing)     next footnote   \n[PD]/2
       \*[FR]      Line length ratio                [4mspecial[24m         11/12
       ────────────────────────────────────────────────────────────────────────

                                  [1mDisplay settings[0m
       [1mParameter               Definition                Effective    Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[DD]      Display distance (spacing)            [4mspecial[24m     0.5v (1v)
       \n[DI]      Display indentation                   [4mspecial[24m     0.5i
       ────────────────────────────────────────────────────────────────────────

                                   [1mOther settings[0m
         [1mParameter               Definition              Effective     Default[0m
       ────────────────────────────────────────────────────────────────────────
       \n[MINGW]       Minimum gutter width             next page      2n
       \n[TC-MARGIN]   TOC page number margin width     next [1mPX [22mcall   \w'000'
       \[TC-LEADER]    TOC leader character             next [1mPX [22mcall   .\h'1m'
       ────────────────────────────────────────────────────────────────────────

       For entries marked “[4mspecial[24m” in the “Effective” column, see the discus‐
       sion  in the applicable section below.  The [1mPO[22m, [1mLL[22m, and [1mLT [22mregister de‐
       faults vary by output device and paper format; the values shown are for
       typesetters using U.S. letter paper, and then terminals.   See  section
       “Paper  format”  of  [4mgroff[24m(1).   The [1mPD [22mand [1mDD [22mregisters use the larger
       value if the vertical motion quantum of the output device is too coarse
       for the smaller one; usually, this is the case only for output to  ter‐
       minals  and  emulators  thereof.  The “gutter” affected by [1m\n[MINGW] [22mis
       the gap between columns  in  multiple‐column  page  arrangements.   The
       [1mTC-MARGIN  [22mregister  and [1mTC-LEADER [22mspecial character affect the format‐
       ting of tables of contents assembled by the [1mXS[22m, [1mXA[22m, and [1mXE [22mmacros.

   [1mDocument description macros[0m
       Define information describing the document by calling the macros  below
       in  the  order shown; [1m.DA [22mor [1m.ND [22mcan be called to set the document date
       (or other identifier) at any time before (a) the abstract, if  present,
       or (b) its information is required in a header or footer.  Use of these
       macros  is  optional,  except that [1m.TL [22mis mandatory if any of [1m.RP[22m, [1m.AU[22m,
       [1m.AI[22m, or [1m.AB [22mis called, and [1m.AE [22mis mandatory if [1m.AB [22mis called.

       [1m.RP [22m[[1mno-repeat-info[22m] [[1mno-renumber[22m]
              Use the “report” (AT&T: “released paper”) format for your  docu‐
              ment,  creating  a separate cover page.  The default arrangement
              is to place most of  the  document  description  (title,  author
              names  and  institutions, and abstract, but not the date) at the
              top of the first page.  If the optional [1mno-repeat-info  [22margument
              is  given,  [4mms[24m  produces a cover page but does not repeat any of
              its information on subsequently (but see the [1mDA [22mmacro below  re‐
              garding the date).  Normally, [1m.RP [22msets the page number following
              the  cover page to 1.  Specifying the optional [1mno-renumber [22margu‐
              ment suppresses this alteration.  Optional arguments  can  occur
              in any order.  “[1mno[22m” is recognized as a synonym of [1mno-repeat-info[0m
              for AT&T compatibility.

       [1m.TL    [22mSpecify  the  document  title.   [4mms[24m collects text on input lines
              following this call into the title until reaching [1m.AU[22m, [1m.AB[22m, or a
              heading or paragraphing macro call.

       [1m.AU    [22mSpecify an author’s name.  [4mms[24m collects text on input lines  fol‐
              lowing this call into the author’s name until reaching [1m.AI[22m, [1m.AB[22m,
              another  [1m.AU[22m,  or a heading or paragraphing macro call.  Call it
              repeatedly to specify multiple authors.

       [1m.AI    [22mSpecify the preceding author’s institution.  An [1m.AU [22mcall is use‐
              fully followed by at most one [1m.AI [22mcall; if there are  more,  the
              last [1m.AI [22mcall controls.  [4mms[24m collects text on input lines follow‐
              ing  this call into the author’s institution until reaching [1m.AU[22m,
              [1m.AB[22m, or a heading or paragraphing macro call.

       [1m.DA [22m[[4mx[24m ...]
              Typeset the current date, or any  arguments  [4mx[24m,  in  the  center
              footer,  and,  if [1m.RP [22mis also called, left‐aligned at the end of
              the document description on the cover page.

       [1m.ND [22m[[4mx[24m ...]
              Typeset the current date, or any arguments [4mx[24m,  if  [1m.RP  [22mis  also
              called,  left‐aligned  at the end of the document description on
              the cover page.  This is [4mgroff[24m [4mms[24m’s default.

       [1m.AB [22m[[1mno[22m]
              Begin the abstract.  [4mms[24m collects text on input  lines  following
              this  call into the abstract until reaching an [1m.AE [22mcall.  By de‐
              fault, [4mms[24m places the word “ABSTRACT”  centered  and  in  italics
              above the text of the abstract.  The optional argument “[1mno[22m” sup‐
              presses this heading.

       [1m.AE    [22mEnd the abstract.

   [1mText settings[0m
       The  [1mFAM  [22mstring,  a GNU extension, sets the font family for body text;
       the default is “[1mT[22m”.  The [1mPS [22mand [1mVS [22mregisters set the type size and ver‐
       tical spacing (distance between  text  baselines),  respectively.   The
       font  family  and  type  size are ignored on terminal devices.  Setting
       these parameters before the first call of a heading,  paragraphing,  or
       (non‐date)  document  description  macro  also applies them to headers,
       footers, and (for [1mFAM[22m) footnotes.

       The [1mHY [22mregister defines the automatic hyphenation mode used with the [1mhy[0m
       request.  Setting [1m\n[HY] [22mto [1m0 [22mis equivalent to using  the  [1mnh  [22mrequest.
       This is a Tenth Edition Research Unix extension.

   [1mTypographical symbols[0m
       [4mms[24m  provides  a  few strings to obtain typographical symbols not easily
       entered with the keyboard.  These and many others are available as spe‐
       cial character escape sequences—see [4mgroff_char[24m(7).

       [1m\*[-]  [22mInterpolate an em dash.

       [1m\*[Q][0m
       [1m\*[U]  [22mInterpolate typographer’s quotation marks where  available,  and
              neutral  double  quotes  otherwise.  [1m\*[Q] [22mis the left quote and
              [1m\*[U] [22mthe right.

   [1mParagraphs[0m
       Paragraphing macros [4mbreak[24m, or terminate, any  pending  output  line  so
       that a new paragraph can begin.  Several paragraph types are available,
       differing  in  how indentation applies to them: to left, right, or both
       margins; to the first output line of the paragraph, all  output  lines,
       or all but the first.  All paragraphing macro calls cause the insertion
       of  vertical  space  in the amount stored in the [1mPD [22mregister, except at
       page or column breaks, or adjacent to displays.

       The [1mPORPHANS [22mregister defines the minimum number of  initial  lines  of
       any paragraph that must be kept together to avoid isolated lines at the
       bottom of a page.  If a new paragraph is started close to the bottom of
       a  page,  and  there  is insufficient space to accommodate [1m\n[PORPHANS][0m
       lines before an automatic page break, then a page break is  forced  be‐
       fore the start of the paragraph.  This is a GNU extension.

       [1m.LP    [22mSet a paragraph without any (additional) indentation.

       [1m.PP    [22mSet a paragraph with a first‐line left indentation in the amount
              stored in the [1mPI [22mregister.

       [1m.IP [22m[[4mmarker[24m [[4mwidth[24m]]
              Set a paragraph with a left indentation.  The optional [4mmarker[24m is
              not  indented  and is empty by default.  [4mwidth[24m overrides the in‐
              dentation amount in [1m\n[PI][22m; its default unit is “[1mn[22m”.  Once spec‐
              ified, [4mwidth[24m applies to further [1m.IP [22mcalls until specified  again
              or a heading or different paragraphing macro is called.

       [1m.QP    [22mSet  a  paragraph  indented  from both left and right margins by
              [1m\n[QI][22m.

       [1m.QS[0m
       [1m.QE    [22mBegin ([1mQS[22m) and end ([1mQE[22m) a region where  each  paragraph  is  in‐
              dented  from  both  margins by [1m\n[QI][22m.  The text between [1m.QS [22mand
              [1m.QE [22mcan be structured  further  by  use  of  other  paragraphing
              macros.

       [1m.XP    [22mSet  an  “exdented”  paragraph—one  with  a  left indentation of
              [1m\n[PI] [22mon every line [4mexcept[24m the first (also known as  a  hanging
              indent).  This is a Berkeley extension.

   [1mHeadings[0m
       Use headings to create a hierarchical structure for your document.  The
       [4mms[24m macros print headings in [1mbold [22musing the same font family and, by de‐
       fault,  type  size  as  the body text.  Headings are available with and
       without automatic numbering.  Text on input lines following  the  macro
       call becomes the heading’s title.  Call a paragraphing macro to end the
       heading text and start the section’s content.

       [1m.NH [22m[[4mdepth[24m]
              Set  an  automatically numbered heading.  [4mms[24m produces a numbered
              heading in the form [4ma[24m.[4mb[24m.[4mc[24m..., to any  level  desired,  with  the
              numbering of each depth increasing automatically and being reset
              to  zero when a more significant depth is increased.  “[1m1[22m” is the
              most significant or coarsest division  of  the  document.   Only
              non‐zero values are output.  If [4mdepth[24m is omitted, it is taken to
              be  [1m1[22m.   If  you specify [4mdepth[24m such that an ascending gap occurs
              relative to the previous [1mNH [22mcall—that is, you “skip a depth”, as
              by “[1m.NH 1[22m” and then “[1m.NH 3[22m”, [4mgroff[24m [4mms[24m emits  a  warning  on  the
              standard error stream.

       [1m.NH S [4m[22mheading‐depth‐index[24m ...
              Alternatively, you can give [1mNH [22ma first argument of “[1mS[22m”, followed
              by  integers  to  number the heading depths explicitly.  Further
              automatic numbering, if used, resumes using  the  specified  in‐
              dices  as their predecessors.  This feature is a Berkeley exten‐
              sion.

       After [1m.NH [22mis called, the assigned  number  is  made  available  in  the
       strings [1mSN-DOT [22m(as it appears in a printed heading with default format‐
       ting,  followed by a terminating period) and [1mSN-NO-DOT [22m(with the termi‐
       nating period omitted).  These are GNU extensions.

       You can control the style used to print numbered headings  by  defining
       an appropriate alias for the string [1mSN-STYLE[22m.  By default, [1m\*[SN-STYLE][0m
       is aliased to [1m\*[SN-DOT][22m.  If you prefer to omit the terminating period
       from  numbers  appearing  in  numbered  headings,  you  may alias it to
       [1m\*[SN-NO-DOT][22m.  Any such change in numbering  style  becomes  effective
       from  the  next  use  of  [1m.NH  [22mfollowing  redefinition of the alias for
       [1m\*[SN-STYLE][22m.  The formatted number of the current heading is available
       in [1m\*[SN] [22m(a feature first documented by Berkeley); this string facili‐
       tates its inclusion in, for example, table captions,  equation  labels,
       and [1m.XS[22m/[1m.XA[22m/[1m.XE [22mtable of contents entries.

       [1m.SH [22m[[4mdepth[24m]
              Set an unnumbered heading.  The optional [4mdepth[24m argument is a GNU
              extension  indicating  the  heading  depth  corresponding to the
              [4mdepth[24m argument of [1m.NH[22m.  It matches the type size  at  which  the
              heading  is  set to that of a numbered heading at the same depth
              when the [1m\n[GROWPS] [22mand [1m\n[PSINCR] [22mheading size adjustment mech‐
              anism is in effect.

       The [1mPSINCR [22mregister defines an increment in type size to be applied  to
       a  heading  at  a  lesser depth than that specified in [1m\n[GROWPS][22m.  The
       value of [1m\n[PSINCR] [22mshould be specified in points with the “[1mp[22m”  scaling
       unit and may include a fractional component.

       The [1mGROWPS [22mregister defines the heading depth above which the type size
       increment  set by [1m\n[PSINCR] [22mbecomes effective.  For each heading depth
       less than the value of  [1m\n[GROWPS][22m,  the  type  size  is  increased  by
       [1m\n[PSINCR][22m.  Setting [1m\n[GROWPS] [22mto a value less than 2 disables the in‐
       cremental heading size feature.

       In  other  words,  if  the value of [1mGROWPS [22mregister is greater than the
       [4mdepth[24m argument to a [1m.NH [22mor [1m.SH [22mcall, the type size of  a  heading  pro‐
       duced  by these macros increases by [1m\n[PSINCR] [22munits over [1m\n[PS] [22mmulti‐
       plied by the difference of [1m\n[GROWPS] [22mand [4mdepth[24m.

       The [1m\n[HORPHANS] [22mregister operates in conjunction with the  [1mNH  [22mand  [1mSH[0m
       macros  to inhibit the printing of isolated headings at the bottom of a
       page; it specifies the minimum number of lines of the subsequent  para‐
       graph  that  must be kept on the same page as the heading.  If insuffi‐
       cient space remains on the current page to accommodate the heading  and
       this  number  of lines of paragraph text, a page break is forced before
       the heading is printed.  Any display macro call or [4mtbl[24m, [4mpic[24m, or [4meqn[24m re‐
       gion between the heading and the subsequent paragraph  suppresses  this
       grouping.

   [1mTypeface and decoration[0m
       The  [4mms[24m macros provide a variety of ways to style text.  Attend closely
       to the ordering of arguments labeled [4mpre[24m and [4mpost,[24m which is  not  intu‐
       itive.  Support for [4mpre[24m arguments is a GNU extension.

       [1m.B [22m[[4mtext[24m [[4mpost[24m [[4mpre[24m]]]
              Style  [4mtext[24m in bold, followed by [4mpost[24m in the previous font style
              without intervening space, and preceded by [4mpre[24m similarly.  With‐
              out arguments, [4mms[24m styles subsequent text in bold until the  next
              paragraphing, heading, or no‐argument typeface macro call.

       [1m.R [22m[[4mtext[24m [[4mpost[24m [[4mpre[24m]]]
              As  [1m.B[22m,  but use the roman style (upright text of normal weight)
              instead of bold.  Argument recognition is a GNU extension.

       [1m.I [22m[[4mtext[24m [[4mpost[24m [[4mpre[24m]]]
              As [1m.B[22m, but use an italic or oblique style instead of bold.

       [1m.BI [22m[[4mtext[24m [[4mpost[24m [[4mpre[24m]]]
              As [1m.B[22m, but use a bold italic or bold oblique  style  instead  of
              upright bold.  This is a Tenth Edition Research Unix extension.

       [1m.CW [22m[[4mtext[24m [[4mpost[24m [[4mpre[24m]]]
              As  [1m.B[22m, but use a constant‐width (monospaced) roman typeface in‐
              stead of bold.  This is a Tenth Edition Research Unix extension.

       [1m.BX [22m[[4mtext[24m]
              Typeset [4mtext[24m and draw a box around it.  On terminal devices, re‐
              verse video is used instead.  If you want [4mtext[24m to contain space,
              use unbreakable space or horizontal motion escape sequences ([1m\~[22m,
              [1m\[4m[22mspace[24m, [1m\^[22m, [1m\|[22m, [1m\0[22m, or [1m\h[22m).

       [1m.UL [22m[[4mtext[24m [[4mpost[24m]]
              Typeset [4mtext[24m with an underline.  [4mpost,[24m if present, is set  after
              [4mtext[24m with no intervening space.

       [1m.LG    [22mSet  subsequent  text  in  larger type (2 points larger than the
              current size) until the next type size, paragraphing, or heading
              macro call.  You can specify this macro multiple  times  to  en‐
              large the type size as needed.

       [1m.SM    [22mSet  subsequent  text in smaller type (2 points smaller than the
              current size) until the next type size, paragraphing, or heading
              macro call.  You can specify this macro multiple times to reduce
              the type size as needed.

       [1m.NL    [22mSet subsequent text at the normal type size ([1m\n[PS][22m).

       When [4mpre[24m is used, a hyphenation control escape sequence [1m\%  [22mthat  would
       ordinarily start [4mtext[24m must start [4mpre[24m instead.

       [4mgroff[24m  [4mms[24m also offers strings to begin and end super‐ and subscripting.
       These are GNU extensions.

       [1m\*{[0m
       [1m\*}    [22mBegin and end superscripting, respectively.

       [1m\*<[0m
       [1m\*>    [22mBegin and end subscripting, respectively.

   [1mIndented regions[0m
       You may need to indent a region of text while otherwise  formatting  it
       normally.  Indented regions can be nested.

       [1m.RS    [22mBegin  a region where headings, paragraphs, and displays are in‐
              dented (further) by [1m\n[PI][22m.

       [1m.RE    [22mEnd the (next) most recent indented region.

   [1mKeeps, boxed keeps, and displays[0m
       On occasion, you may want to [4mkeep[24m several lines of text, or a region of
       a document, together on a single page,  preventing  an  automatic  page
       break  within certain boundaries.  This can cause a page break to occur
       earlier than it normally would.

       You can alternatively specify a [4mfloating[24m [4mkeep:[24m if a keep cannot fit  on
       the  current  page, [4mms[24m holds its contents and allows text following the
       keep (in the source document) to fill in the remainder of  the  current
       page.  When the page breaks, whether by reaching the end or [1mbp [22mrequest,
       [4mms[24m puts the floating keep at the beginning of the next page.

       [1m.KS    [22mBegin a keep.

       [1m.KF    [22mBegin a floating keep.

       [1m.KE    [22mEnd (floating) keep.

       As  an  alternative to the keep mechanism, the [1mne [22mrequest forces a page
       break if there is not at least the amount of vertical  space  specified
       in its argument remaining on the page.

       A [4mboxed[24m [4mkeep[24m has a frame drawn around it.

       [1m.B1    [22mBegin a keep with a box drawn around it.

       [1m.B2    [22mEnd boxed keep.

       Boxed  keep  macros  cause  breaks; if you need to box a word or phrase
       within a line, see the [1mBX [22mmacro in section “Highlighting”  above.   Box
       lines  are  drawn as close as possible to the text they enclose so that
       they are usable within paragraphs.  If you wish to place  one  or  more
       paragraphs in a boxed keep, you may improve their appearance by calling
       [1m.B1 [22mafter the first paragraphing macro, and by adding a small amount of
       vertical space before calling [1m.B2[22m.

       If you want a boxed keep to float, you will need to enclose the [1m.B1 [22mand
       [1m.B2 [22mcalls within a pair of [1m.KF [22mand [1m.KE [22mcalls.

       [4mDisplays[24m  turn  off  filling;  lines of verse or program code are shown
       with their lines broken as in the source document without requiring  [1mbr[0m
       requests  between  lines.  Displays can be kept on a single page or al‐
       lowed to break across pages.  The [1mDS [22mmacro begins a kept display of the
       layout specified in its first argument;  non‐kept  displays  are  begun
       with dedicated macros corresponding to their layout.

       [1m.DS L[0m
       [1m.LD    [22mBegin ([1mDS[22m: kept) left‐aligned display.

       [1m.DS [22m[[1mI [22m[[4mindent[24m]]
       [1m.ID [22m[[4mindent[24m]
              Begin ([1mDS[22m: kept) display indented by [4mindent[24m if specified, [1m\n[DI][0m
              otherwise.

       [1m.DS B[0m
       [1m.BD    [22mBegin  ([1mDS[22m:  kept)  block  display:  the entire display is left‐
              aligned, but indented such that the longest line in the  display
              is centered on the page.

       [1m.DS C[0m
       [1m.CD    [22mBegin  ([1mDS[22m:  kept) centered display: each line in the display is
              centered.

       [1m.DS R[0m
       [1m.RD    [22mBegin ([1mDS[22m: kept) right‐aligned display.  This is  a  GNU  exten‐
              sion.

       [1m.DE    [22mEnd any display.

       The distance stored in [1m\n[DD] [22mis inserted before and after each pair of
       display  macros;  this is a Berkeley extension.  In [4mgroff[24m [4mms[24m, this dis‐
       tance replaces any  adjacent  inter‐paragraph  distance  or  subsequent
       spacing  prior  to  a section heading.  The [1mDI [22mregister is a GNU exten‐
       sion; its value is an indentation applied to displays created with  [1m.DS[0m
       and  [1m.ID [22mwithout arguments, to “[1m.DS I[22m” without an indentation argument,
       and to equations set with “[1m.EQ I[22m”.  Changes to either register take ef‐
       fect at the next display boundary.

   [1mTables, figures, equations, and references[0m
       The [4mms[24m package is often used with the [4mtbl[24m, [4mpic[24m,  [4meqn[24m,  and  [4mrefer[24m  pre‐
       processors.  The [1m\n[DD] [22mdistance is also applied to regions of the doc‐
       ument  preprocessed  with  [4meqn[24m, [4mpic[24m, and [4mtbl[24m.  Mark text meant for pre‐
       processors by enclosing it in pairs of tokens as follows, with  nothing
       between  the dot and the macro name.  The preprocessors match these to‐
       kens only at the start of an input line.

       [1m.TS [22m[[1mH[22m]
       [1m.TE    [22mDemarcate a table to be processed by the [4mtbl[24m preprocessor.   The
              optional  [1mH  [22margument  instructs  [4mms[24m to repeat table rows (often
              column headings) at the top of each new page the table spans, if
              applicable; calling the [1mTH [22mmacro marks the  end  of  such  rows.
              [4mtbl[24m(1)  provides  a  comprehensive reference to the preprocessor
              and offers examples of its use.

       [1m.PS[0m
       [1m.PE[0m
       [1m.PF    .PS [22mbegins a picture to be processed by  the  [4mpic[24m  preprocessor;
              either  of  [1m.PE [22mor [1m.PF [22mends it, the latter with “flyback” to the
              vertical position at its top.

       [1m.EQ [22m[[4malign[24m [[4mlabel[24m]]
       [1m.EN    [22mDemarcate an equation to be processed by the  [4meqn[24m  preprocessor.
              The  equation is centered by default; [4malign[24m can be [1mC[22m, [1mL[22m, or [1mI [22mto
              (explicitly) center, left‐align, or indent it by [1m\n[DI][22m, respec‐
              tively.  If specified, [4mlabel[24m is set right‐aligned.

       [1m.[[0m
       [1m.]     [22mDemarcate a bibliographic citation to be processed by the  [4mrefer[0m
              preprocessor.   [4mrefer[24m(1)  provides  a comprehensive reference to
              the preprocessor and the format of its bibliographic database.

       When [4mrefer[24m emits collected references (as might be  done  on  a  “Works
       Cited”  page),  it  interpolates the string [1m\*[REFERENCES] [22mas an unnum‐
       bered heading ([1m.SH[22m).

       Attempting to place a multi‐page table inside a keep can  lead  to  un‐
       pleasant results, particularly if the [4mtbl[24m “[1mallbox[22m” option is used.

   [1mFootnotes[0m
       A  footnote is typically anchored to a place in the text with a [4mmarker,[0m
       which is a small integer, a symbol, or arbitrary user‐specified text.

       [1m\**    [22mPlace an [4mautomatic[24m [4mnumber,[24m an  automatically  generated  numeric
              footnote marker, in the text.  Each time this string is interpo‐
              lated, the number it produces increments by one.  Automatic num‐
              bers start at 1.  This is a Berkeley extension.

       Enclose  the  footnote  text  in [1mFS [22mand [1mFE [22mmacro calls to set it at the
       nearest available “foot”, or bottom, of a text column or page.

       [1m.FS [22m[[4mmarker[24m]
              Begin a footnote.  The [1m.FS-MARK [22mhook (see below) is called  with
              any  supplied  [4mmarker[24m argument, which is then also placed at the
              beginning of the footnote text.  If [4mmarker[24m is omitted, the  next
              pending  automatic  number  enqueued  by  interpolation of the [1m*[0m
              string is used, and if none exists, nothing is prefixed.

       [1m.FE    [22mEnd footnote text.

       [4mgroff[24m [4mms[24m provides a hook macro, [1mFS-MARK[22m, for user‐determined operations
       to be performed when the [1mFS [22mmacro is called.  It is passed the same ar‐
       guments as [1m.FS [22mitself.  By default, this macro has an empty definition.
       [1m.FS-MARK [22mis a GNU extension.

       Footnote text is formatted as paragraphs are, using  analogous  parame‐
       ters.   The  registers  [1mFI[22m, [1mFPD[22m, [1mFPS[22m, and [1mFVS [22mcorrespond to [1mPI[22m, [1mPD[22m, [1mPS[22m,
       and [1mVS[22m, respectively; [1mFPD[22m, [1mFPS[22m, and [1mFVS [22mare GNU extensions.

       The [1mFF [22mregister controls the formatting of automatically numbered foot‐
       note paragraphs, and those for which [1m.FS [22mis given a [4mmarker[24m argument, at
       the bottom of a column or page as follows.

              0      Set an automatic number, or a specified [1mFS  [4m[22mmarker[24m  argu‐
                     ment,  as  a  superscript (on typesetter devices) or sur‐
                     rounded by square brackets (on terminals).  The  footnote
                     paragraph  is indented as with [1m.PP [22mif there is an [1m.FS [22mar‐
                     gument or an automatic number, and as with [1m.LP [22motherwise.
                     This is the default.

              1      As [1m0[22m, but set the marker as regular text, and  follow  an
                     automatic number with a period.

              2      As [1m1[22m, but without indentation (like [1m.LP[22m).

              3      As  [1m1[22m,  but  set  the  footnote paragraph with the marker
                     hanging (like [1m.IP[22m).

   [1mLanguage and localization[0m
       [4mgroff[24m [4mms[24m provides several strings that you can customize for  your  own
       purposes,  or  redefine  to  adapt the macro package to languages other
       than English.  It is already localized for Czech, German, French, Ital‐
       ian, and Swedish.  Load the desired localization  macro  package  after
       [4mms[24m; see [4mgroff_tmac[24m(5).

                  [1mString            Default[0m
              ───────────────────────────────────
              \*[REFERENCES]   References
              \*[ABSTRACT]     \f[I]ABSTRACT\f[]
              \*[TOC]          Table of Contents
              \*[MONTH1]       January
              \*[MONTH2]       February
              \*[MONTH3]       March
              \*[MONTH4]       April
              \*[MONTH5]       May
              \*[MONTH6]       June
              \*[MONTH7]       July
              \*[MONTH8]       August
              \*[MONTH9]       September
              \*[MONTH10]      October
              \*[MONTH11]      November
              \*[MONTH12]      December
              ───────────────────────────────────
       The  default  for  [1mABSTRACT [22mincludes font selection escape sequences to
       set the word in italics.

   [1mHeaders and footers[0m
       There are multiple ways to produce headers and footers.  One is to  de‐
       fine  the  strings  [1mLH[22m,  [1mCH[22m,  and [1mRH [22mto set the left, center, and right
       headers, respectively; and [1mLF[22m, [1mCF[22m, and [1mRF [22mto set the left, center,  and
       right  footers.   This approach suffices for documents that do not dis‐
       tinguish odd‐ and even‐numbered pages.

       Another method is to call macros that set headers or footers  for  odd‐
       or  even‐numbered  pages.   Each  such macro takes a delimited argument
       separating the left, center, and right header or footer texts from each
       other.  You can replace the neutral apostrophes (')  shown  below  with
       any character not appearing in the header or footer text.  These macros
       are Berkeley extensions.

       [1m.OH [22m'[4mleft[24m'[4mcenter[24m'[4mright[24m'
       [1m.OF [22m'[4mleft[24m'[4mcenter[24m'[4mright[24m'
       [1m.EH [22m'[4mleft[24m'[4mcenter[24m'[4mright[24m'
       [1m.EF [22m'[4mleft[24m'[4mcenter[24m'[4mright[24m'
              The  [1mOH  [22mand [1mEH [22mmacros define headers for odd‐ (recto) and even‐
              numbered (verso) pages, respectively; the [1mOF [22mand [1mEF  [22mmacros  de‐
              fine footers for them.

       With  either  method,  a percent sign [1m% [22min header or footer text is re‐
       placed by the current page number.  By default, [4mms[24m places no header  on
       a page numbered “1” (regardless of its number format).

       [1m.P1    [22mTypeset  the header even on page 1.  To be effective, this macro
              must be called before the header trap is sprung on any page num‐
              bered “1”.  This is a Berkeley extension.

       For even greater flexibility, [4mms[24m permits  redefinition  of  the  macros
       called  when  the  page  header and footer traps are sprung.  [1mPT [22m(“page
       trap”) is called by [4mms[24m when the header is to be written, and [1mBT  [22m(“bot‐
       tom trap”) when the footer is to be.  The [4mgroff[24m page location trap that
       [4mms[24m  sets up to format the header also calls the (normally undefined) [1mHD[0m
       macro after [1m.PT[22m; you can define [1m.HD [22mif you need  additional  processing
       after  setting  the  header.  The [1mHD [22mhook is a Berkeley extension.  Any
       such macros you (re)define must implement  any  desired  specialization
       for odd‐, even‐, or first numbered pages.

   [1mTab stops[0m
       Use the [1mta [22mrequest to set tab stops as needed.

       [1m.TA    [22mReset  the  tab stops to the [4mms[24m default (every 5 ens).  Redefine
              this macro to create a different set of default tab stops.

   [1mMargins[0m
       Control margins using the registers summarized in the “Margins” portion
       of the table in section “Document control settings” above.  There is no
       setting for the right margin; the combination of page offset [1m\n[PO] [22mand
       line length [1m\n[LL] [22mdetermines it.

   [1mMultiple columns[0m
       [4mms[24m can set text in as many columns as reasonably fit on the page.   The
       following  macros force a page break if a multi‐column layout is active
       when they are called.  [1m\n[MINGW] [22mis the default minimum  gutter  width;
       it is a GNU extension.  When multiple columns are in use, keeps and the
       [1mHORPHANS  [22mand [1mPORPHANS [22mregisters work with respect to column breaks in‐
       stead of page breaks.

       [1m.1C    [22mArrange page text in a single column (the default).

       [1m.2C    [22mArrange page text in two columns.

       [1m.MC [22m[[4mcolumn‐width[24m [[4mgutter‐width[24m]]
              Arrange page text in multiple columns.  If you specify no  argu‐
              ments,  it  is  equivalent  to the [1m2C [22mmacro.  Otherwise, [4mcolumn‐[0m
              [4mwidth[24m is the width of each column and [4mgutter‐width[24m is the  mini‐
              mum distance between columns.

   [1mCreating a table of contents[0m
       Define  an  entry  to appear in the table of contents by bracketing its
       text between calls to the [1mXS [22mand [1mXE [22mmacros.  A typical  application  is
       to  call  them  immediately  after [1mNH [22mor [1mSH [22mand repeat the heading text
       within them.  The [1mXA [22mmacro, used within [1m.XS[22m/[1m.XE [22mpairs,  supplements  an
       entry—for instance, when it requires multiple output lines, whether be‐
       cause  a heading is too long to fit or because style dictates that page
       numbers not be repeated.  You may wish to indent the text thus  wrapped
       to  correspond to its heading depth; this can be done in the entry text
       by prefixing it with tabs or horizontal motion escape sequences, or  by
       providing a second argument to the [1mXA [22mmacro.  [1m.XS [22mand [1m.XA [22mautomatically
       associate the page number where they are called with the text following
       them,  but they accept arguments to override this behavior.  At the end
       of the document, call [1mTC [22mor [1mPX [22mto emit the table of contents;  [1m.TC  [22mre‐
       sets  the page number to [1mi [22m(Roman numeral one), and then calls [1mPX[22m.  All
       of these macros are Berkeley extensions.

       [1m.XS [22m[[4mpage‐number[24m]
       [1m.XA [22m[[4mpage‐number[24m [[4mindentation[24m]]
       [1m.XE    [22mBegin, supplement, and end a table of contents entry.  Each  en‐
              try  is  associated with [4mpage‐number[24m (otherwise the current page
              number); a [4mpage‐number[24m of “[1mno[22m” prevents a leader and page number
              from being emitted for that entry.  Use of [1m.XA [22mwithin [1m.XS[22m/[1m.XE [22mis
              optional; it can be repeated.  If [4mindentation[24m is present, a sup‐
              plemental entry is indented by that amount; ens are  assumed  if
              no  unit  is indicated.  Text on input lines between [1m.XS [22mand [1m.XE[0m
              is stored for later recall by [1m.PX[22m.

       [1m.PX [22m[[1mno[22m]
              Switch to single‐column layout.  Unless “[1mno[22m” is specified,  cen‐
              ter  and  interpolate [1m\*[TOC] [22min bold and two points larger than
              the body text.  Emit the table of contents entries.

       [1m.TC [22m[[1mno[22m]
              Set the page number to 1, the page number  format  to  lowercase
              Roman numerals, and call [1mPX [22m(with a “[1mno[22m” argument, if present).

       The remaining features in this subsection are GNU extensions.  [4mgroff[24m [4mms[0m
       obviates the need to repeat heading text after [1m.XS [22mcalls.  Call [1m.XN [22mand
       [1m.XH  [22mafter  [1m.NH [22mand [1m.SH[22m, respectively.  Text to be appended to the for‐
       matted section heading, but not to appear in the table of contents  en‐
       try, can follow these calls.

       [1m.XN [4m[22mheading‐text[0m
              Format [4mheading‐text[24m and create a corresponding table of contents
              entry;  the  indentation  is computed from the [4mdepth[24m argument of
              the preceding [1mNH [22mcall.

       [1m.XH [4m[22mdepth[24m [4mheading‐text[0m
              As [1m.XN[22m, but use [4mdepth[24m to determine the indentation.

       [4mgroff[24m [4mms[24m encourages customization of table of  contents  entry  produc‐
       tion.  (Re‐)define any of the following macros as desired.

       [1m.XN-REPLACEMENT [4m[22mheading‐text[0m
       [1m.XH-REPLACEMENT [4m[22mdepth[24m [4mheading‐text[0m
              These  hook  macros  implement [1m.XN [22mand [1m.XH[22m, and call [1mXN-INIT [22mand
              [1mXH-INIT[22m, respectively, then call [1mXH-UPDATE-TOC  [22mwith  the  argu‐
              ments given them.

       [1m.XH-INIT[0m
       [1m.XN-INIT[0m
              These hook macros do nothing by default.

       [1m.XH-UPDATE-TOC [4m[22mdepth[24m [4mheading‐text[0m
              Bracket [4mheading‐text[24m with [1mXS [22mand [1mXE [22mcalls, indenting it by 2 ens
              per level of [4mdepth[24m beyond the first.

       You  can  customize  the style of the leader that bridges each table of
       contents entry with its page number; define the [1mTC-LEADER [22mspecial char‐
       acter by using the [1mchar [22mrequest.  A typical  leader  combines  the  dot
       glyph  “[1m.[22m” with a horizontal motion escape sequence to spread the dots.
       The width of the page number field is stored in the [1mTC-MARGIN [22mregister.

[1mDifferences from AT&T [4mms[0m
       The [4mgroff[24m [4mms[24m macros are an independent reimplementation, using no  AT&T
       code.   Since  they  take  advantage of the extended features of [4mgroff[24m,
       they cannot be used with AT&T [4mtroff[24m.  [4mgroff[24m [4mms[24m  supports  features  de‐
       scribed  above  as Berkeley and Tenth Edition Research Unix extensions,
       and adds several of its own.

       •  The internals of [4mgroff[24m [4mms[24m differ from  the  internals  of  AT&T  [4mms[24m.
          Documents that depend upon implementation details of AT&T [4mms[24m may not
          format  properly  with  [4mgroff[24m [4mms[24m.  Such details include macros whose
          function was not documented in the AT&T [4mms[24m manual (“Typing Documents
          on the UNIX System: Using the -ms Macros with Troff and  Nroff”,  M.
          E. Lesk, Bell Laboratories, 1978).

       •  The  error‐handling  policy  of [4mgroff[24m [4mms[24m is to detect and report er‐
          rors, rather than to ignore them silently.

       •  Tenth Edition Research Unix supported [1mP1[22m/[1mP2 [22mmacros to  bracket  code
          examples; [4mgroff[24m [4mms[24m does not.

       •  [4mgroff[24m  [4mms[24m  does not work in GNU [4mtroff[24m’s AT&T compatibility mode.  If
          loaded when that mode is enabled, it aborts processing with a  diag‐
          nostic message.

       •  Multiple line spacing is not supported.  Use a larger vertical spac‐
          ing instead.

       •  [4mgroff[24m  [4mms[24m uses the same header and footer defaults in both [4mnroff[24m and
          [4mtroff[24m modes as AT&T [4mms[24m does in [4mtroff[24m mode; AT&T’s default  in  [4mnroff[0m
          mode  is to put the date, in U.S. traditional format (e.g., “January
          1, 2021”), in the center footer (the [1mCF [22mstring).

       •  Many [4mgroff[24m [4mms[24m macros, including those for paragraphs, headings,  and
          displays,  cause  a reset of paragraph rendering parameters, and may
          change the indentation; they do so not by incrementing or decrement‐
          ing it, but by setting it absolutely.  This can cause  problems  for
          documents that define additional macros of their own that try to ma‐
          nipulate indentation.  Use [1m.RS [22mand [1m.RE [22minstead of the [1min [22mrequest.

       •  AT&T [4mms[24m interpreted the values of the registers [1mPS [22mand [1mVS [22min points,
          and  did  not  support the use of scaling units with them.  [4mgroff[24m [4mms[0m
          interprets values of the registers [1mPS[22m, [1mVS[22m, [1mFPS[22m, and [1mFVS[22m, equal to or
          larger than 1,000 (one thousand)  as  decimal  fractions  multiplied
          by  1,000.   (Register  values  are converted to and stored as basic
          units.  See  “Measurements”  in  the  [4mgroff[24m  Texinfo  manual  or  in
          [4mgroff[24m(7)).   This  threshold  makes use of a scaling unit with these
          parameters practical for high‐resolution  devices  while  preserving
          backward  compatibility.  It also permits expression of non‐integral
          type sizes.  For example, “[1mgroff -rPS=10.5p[22m” at the shell prompt  is
          equivalent  to  placing “[1m.nr PS 10.5p[22m” at the beginning of the docu‐
          ment.

       •  AT&T [4mms[24m’s [1mAU [22mmacro  supported  arguments  used  with  some  document
          types; [4mgroff[24m [4mms[24m does not.

       •  Right‐aligned  displays  are available.  The AT&T [4mms[24m manual observes
          that “it is tempting to assume that “[1m.DS R[22m” will right adjust lines,
          but it doesn’t work”.  In [4mgroff[24m [4mms[24m, it does.

       •  To make [4mgroff[24m [4mms[24m use the default page offset (which  also  specifies
          the  left  margin),  the  [1mPO  [22mregister must stay undefined until the
          first [4mms[24m macro is called.  This implies that [1m\n[PO]  [22mshould  not  be
          used  early in the document, unless it is changed also: accessing an
          undefined register automatically defines it.

       •  [4mgroff[24m [4mms[24m supports the [1mPN [22mregister, but it is not necessary; you  can
          access  the  page  number via the usual [1m% [22mregister and invoke the [1maf[0m
          request to assign a different format to it if desired.  (If you  re‐
          define  the [4mms[24m [1mPT [22mmacro and desire special treatment of certain page
          numbers—like “[1m1[22m”—you may need to handle  a  non‐Arabic  page  number
          format, as [4mgroff[24m [4mms[24m’s [1m.PT [22mdoes; see the macro package source.  [4mgroff[0m
          [4mms[24m aliases the [1mPN [22mregister to [1m%[22m.)

       •  The  AT&T [4mms[24m manual documents registers [1mCW [22mand [1mGW [22mas setting the de‐
          fault column width and “intercolumn gap”,  respectively,  and  which
          applied when [1m.MC [22mwas called with fewer than two arguments.  [4mgroff[24m [4mms[0m
          instead  treats  [1m.MC [22mwithout arguments as synonymous with [1m.2C[22m; there
          is thus no occasion for a default column width  register.   Further,
          the  [1mMINGW [22mregister and the second argument to [1m.MC [22mspecify a [4mminimum[0m
          space between columns, not the fixed gutter width of AT&T [4mms[24m.

       •  The AT&T [4mms[24m manual did not document the [1mQI  [22mregister;  Berkeley  and
          [4mgroff[24m [4mms[24m do.

       •  The  register [1mGS [22mis set to 1 by the [4mgroff[24m [4mms[24m macros, but is not used
          by the AT&T [4mms[24m package.  Documents that need  to  determine  whether
          they  are  being  formatted  with [4mgroff[24m [4mms[24m or another implementation
          should test this register.

   [1mUnix Version 7 macros not implemented by [4mgroff[24m [4mms[0m
       Several macros described in the Unix Version  7  [4mms[24m  documentation  are
       unimplemented by [4mgroff[24m [4mms[24m because they are specific to the requirements
       of  documents  produced  internally by Bell Laboratories, some of which
       also require a glyph for the Bell System logo that [4mgroff[24m does not  sup‐
       port.   These macros implemented several document type formats ([1mEG[22m, [1mIM[22m,
       [1mMF[22m, [1mMR[22m, [1mTM[22m, [1mTR[22m), were meaningful only in conjunction with  the  use  of
       certain  document  types  ([1mAT[22m,  [1mCS[22m,  [1mCT[22m, [1mOK[22m, [1mSG[22m), stored the postal ad‐
       dresses of Bell Labs sites ([1mHO[22m, [1mIH[22m, [1mMH[22m, [1mPY[22m, [1mWH[22m), or lacked a stable de‐
       finition over time ([1mUX[22m).

[1mLegacy features[0m
       [4mgroff[24m [4mms[24m retains some legacy features solely to support  formatting  of
       historical  documents;  contemporary  ones  should not use them because
       they can render poorly.  See [4mgroff_char[24m(7) instead.

   [1mAT&T [4mms[24m accent mark strings[0m
       AT&T [4mms[24m defined accent mark strings as follows.

       [1mString   Description[0m
       ──────────────────────────────────────────────────────
       \*[']    Apply acute accent to subsequent glyph.
       \*[`]    Apply grave accent to subsequent glyph.
       \*[:]    Apply dieresis (umlaut) to subsequent glyph.
       \*[^]    Apply circumflex accent to subsequent glyph.
       \*[~]    Apply tilde accent to subsequent glyph.
       \*[C]    Apply caron to subsequent glyph.
       \*[,]    Apply cedilla to subsequent glyph.

   [1mBerkeley [4mms[24m accent mark and glyph strings[0m
       Berkeley [4mms[24m offered an [1mAM [22mmacro; calling it redefined the  AT&T  accent
       mark strings (except for [1m\*C[22m), applied them to the [4mpreceding[24m glyph, and
       defined additional strings, some for spacing glyphs.

       [1m.AM    [22mEnable alternative accent mark and glyph‐producing strings.

       [1mString   Description[0m
       ───────────────────────────────────────────────────────────────
       \*[']    Apply acute accent to preceding glyph.
       \*[`]    Apply grave accent to preceding glyph.
       \*[:]    Apply dieresis (umlaut) to preceding glyph.
       \*[^]    Apply circumflex accent to preceding glyph.
       \*[~]    Apply tilde accent to preceding glyph.
       \*[,]    Apply cedilla to preceding glyph.
       \*[/]    Apply stroke (slash) to preceding glyph.
       \*[v]    Apply caron to preceding glyph.
       \*[_]    Apply macron to preceding glyph.
       \*[.]    Apply underdot to preceding glyph.
       \*[o]    Apply ring accent to preceding glyph.
       ───────────────────────────────────────────────────────────────
       \*[?]    Interpolate inverted question mark.
       \*[!]    Interpolate inverted exclamation mark.
       \*[8]    Interpolate small letter sharp s.
       \*[q]    Interpolate small letter o with hook accent (ogonek).
       \*[3]    Interpolate small letter yogh.
       \*[d‐]   Interpolate small letter eth.
       \*[D‐]   Interpolate capital letter eth.
       \*[th]   Interpolate small letter thorn.
       \*[TH]   Interpolate capital letter thorn.
       \*[ae]   Interpolate small ae ligature.
       \*[AE]   Interpolate capital ae ligature.
       \*[oe]   Interpolate small oe ligature.
       \*[OE]   Interpolate capital oe ligature.

[1mNaming conventions[0m
       The  following  conventions  are used for names of macros, strings, and
       registers.  External names available to documents that use the [4mgroff[24m [4mms[0m
       macros contain only uppercase letters and digits.

       Internally, the macros are divided into modules.  Conventions for iden‐
       tifier names are as follows.

       •  Names used only within one module are of the form [4mmodule[24m[1m*[4m[22mname[24m.

       •  Names used outside the module in which they are defined are  of  the
          form [4mmodule[24m[1m@[4m[22mname[24m.

       •  Names  associated  with  a  particular  environment  are of the form
          [4menvironment[24m[1m:[4m[22mname[24m; these are used only within the [1mpar [22mmodule.

       •  [4mname[24m does not have a module prefix.

       •  Constructed  names  used  to  implement  arrays  are  of  the   form
          [4marray[24m[1m![4m[22mindex[24m.

       Thus the [4mgroff[24m [4mms[24m macros reserve the following names:

       •  Names containing the characters [1m*[22m, [1m@[22m, and [1m:[22m.

       •  Names containing only uppercase letters and digits.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/s.tmac[0m
              implements the package.

       [4m/usr/share/groff/1.23.0/tmac/refer-ms.tmac[0m
              implements [4mrefer[24m(1) support for [4mms[24m.

       [4m/usr/share/groff/1.23.0/tmac/ms.tmac[0m
              is  a  wrapper  enabling the package to be loaded with “[1mgroff -m[0m
              [1mms[22m”.

[1mAuthors[0m
       The GNU version of the [4mms[24m macro package was written by James Clark  and
       contributors.   This  document  was  written  by  Clark,  Larry  Kollar
       ⟨lkollar@despammed.com⟩, and G. Branden  Robinson  ⟨g.branden.robinson@
       gmail.com⟩.

[1mSee also[0m
       A  manual is available in source and rendered form.  On your system, it
       may be compressed and/or available in additional formats.

       [4m/usr/share/doc/groff-1.23.0/ms.ms[0m
       [4m/usr/share/doc/groff-1.23.0/ms.ps[0m
              “Using [4mgroff[24m with  the  [4mms[24m  Macro  Package”;  Larry  Kollar  and
              G. Branden Robinson.

       [4m/usr/share/doc/groff-1.23.0/msboxes.ms[0m
       [4m/usr/share/doc/groff-1.23.0/msboxes.pdf[0m
              “Using  PDF  boxes  with  [4mgroff[24m  and the [4mms[24m macros”; Deri James.
              [1mBOXSTART [22mand [1mBOXSTOP [22mmacros are available via the [4msboxes[24m  exten‐
              sion package, enabling colored, bordered boxes when the [1mpdf [22mout‐
              put device is used.

       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       [4mgroff[24m(1), [4mtroff[24m(1), [4mtbl[24m(1), [4mpic[24m(1), [4meqn[24m(1), [4mrefer[24m(1)

groff 1.23.0                      5 July 2023                      [4mgroff_ms[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_rfc1345[24m(7)       Miscellaneous Information Manual       [4mgroff_rfc1345[24m(7)

[1mName[0m
       groff_rfc1345 - special character names from RFC 1345 and Vim digraphs

[1mDescription[0m
       The  file  [4mrfc1345.tmac[24m  defines special character escape sequences for
       [4mgroff[24m(7) based on the glyph mnemonics specified in RFC 1345 and the di‐
       graph table of the text editor Vim.  Each escape sequence translates to
       a Unicode code point, and will render correctly if the underlying  font
       is a Unicode font that covers the code point.

       For example, “[1m\[Rx][22m” is the “recipe” or “prescription take” symbol, and
       maps  to the code point U+211E.  [4mgroff[24m lets you write it as “[1m\[u211E][22m”,
       but “[1m\[Rx][22m” is more mnemonic.

       For  a  list  of  the  glyph  names  provided,  please  see  the   file
       [4mrfc1345.tmac[24m, which contains definitions of the form
              .char \[Rx] \[u211E]    \" PRESCRIPTION TAKE
       where  [1m.char[22m’s  first argument defines a [4mgroff[24m special character escape
       sequence with a mnemonic glyph name, its second argument is  a  special
       character  escape sequence based on the code point, and the comment de‐
       scribes the glyph defined.

       The RFC 1345 glyph names cover a wide range of Unicode code points, in‐
       cluding supplemental Latin, Greek, Cyrillic, Hebrew, Arabic,  Hiragana,
       Katakana,  and  Bopomofo  letters, punctuation, math notation, currency
       symbols, industrial and entertainment icons, and box‐drawing symbols.

       The Vim digraph table is practically a subset of RFC 1345  (being  lim‐
       ited  to two‐character mnemonics), but, as a newer implementation, adds
       four mnemonics not specified in the RFC (the horizontal  ellipsis,  the
       Euro sign, and two mappings for the rouble sign).  These have also been
       added to [4mrfc1345.tmac[24m.

       [4mrfc1345.tmac[24m contains a total of 1,696 glyph names.  It is not an error
       to load [4mrfc1345.tmac[24m if your font does not have all the glyphs, as long
       as it contains the glyphs that you actually use in your document.

       The  RFC 1345 mnemonics are not identical in every case to the mappings
       for special character glyph names that are built in to [4mgroff[24m; for exam‐
       ple, “[1m\[<<][22m” means the “much less than” sign (U+226A) when [4mrfc1345.tmac[0m
       is not loaded and this special character is not otherwise defined by  a
       document  or  macro  package.   [4mrfc1345.tmac[24m  redefines  “[1m\[<<][22m” to the
       “left‐pointing   double   angle   quotation   mark”   (U+00AB).     See
       [4mgroff_char[24m(7)  for the full list of predefined special character escape
       sequences.

   [1mUsage[0m
       Load the [4mrfc1345.tmac[24m file.  This can be done by  either  adding  “[1m.mso[0m
       [1mrfc1345.tmac[22m” to your document before the first use of any of the glyph
       names  the  macro  file  defines,  or  by using the [4mtroff[24m(1) option “[1m-m[0m
       [1mrfc1345[22m” from the shell.

   [1mBugs[0m
       As the [4mgroff[24m Texinfo manual notes, “[o]nly the current font is  checked
       for  ligatures  and  kerns;  neither special fonts nor entities defined
       with the [1mchar [22mrequest (and its siblings) are taken into account.”  Many
       of the characters defined in [4mrfc1345.tmac[24m are accented  Latin  letters,
       and  will  be  affected by this deficiency, producing subpar typography
       ⟨https://savannah.gnu.org/bugs/?59932⟩.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/rfc1345.tmac[0m
              implements the character mappings.

[1mAuthors[0m
       [4mrfc1345.tmac[24m was contributed by Dorai Sitaram ⟨ds26gte@yahoo.com⟩.

[1mSee also[0m
       RFC 1345 ⟨https://tools.ietf.org/html/rfc1345⟩, by Keld Simonsen,  June
       1992.

       The  Vim  digraph  table  can be listed using the [4mvim[24m(1) command “[1m:help[0m
       [1mdigraph-table[22m”.

       [4mgroff_char[24m(7)

groff 1.23.0                      5 July 2023                 [4mgroff_rfc1345[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_trace[24m(7)         Miscellaneous Information Manual         [4mgroff_trace[24m(7)

[1mName[0m
       groff_trace - macros for debugging GNU [4mroff[24m documents

[1mSynopsis[0m
       [1mgroff -m trace [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       [4mtrace[24m is a macro package for the [4mgroff[24m(7) document  formatting  system,
       designed as an aid for debugging documents written in its language.  It
       issues  a  message  to the standard error stream upon entry to and exit
       from each macro call.  This can ease the process of isolating errors in
       macro definitions.

       Activate the package by specifying the command‐line option  “[1m-m  trace[22m”
       to  the formatter program (often [4mgroff[24m(1)).  You can achieve finer con‐
       trol by including the macro file within the document;  invoke  the  [1mmso[0m
       request,  as  in “[1m.mso trace.tmac[22m”.  Only macros that are defined after
       this invocation are traced.  If the [1mtrace-full [22mregister  is  set  to  a
       true value, as with the command‐line option “[1m-r trace-full=1[22m”, register
       and  string  assignments,  along  with  some other requests, are traced
       also.  If another macro package should be traced as  well,  specify  it
       after “[1m-m trace[22m” on the command line.

       The  macro  file  [4mtrace.tmac[24m is unusual because it does not contain any
       macros to be called by a user.  Instead, [4mgroff[24m’s macro  definition  and
       alteration  facilities  are  wrapped  such that they display diagnostic
       messages.

   [1mLimitations[0m
       Because [4mtrace.tmac[24m wraps the [1mde [22mrequest (and its cousins), macro  argu‐
       ments are expanded one level more.  This causes problems if an argument
       uses  four or more backslashes to delay interpretation of an escape se‐
       quence.  For example, the macro call
              .foo \\\\n[bar]
       normally passes “\\n[bar]” to macro “foo”, but with  [1mde  [22mredefined,  it
       passes “\n[bar]” instead.

       The  solution  to this problem is to use [4mgroff[24m’s [1m\E [22mescape sequence, an
       escape character that is not interpreted in copy mode.
              .foo \En[bar]

[1mExamples[0m
       We will illustrate [4mtrace.tmac[24m using the shell’s “here document” feature
       to supply [4mgroff[24m with a document on the standard input stream.  Since we
       are interested only in diagnostic messages appearing  on  the  standard
       error  stream, we discard the formatted output by redirecting the stan‐
       dard output stream to [4m/dev/null[24m.

   [1mObserving nested macro calls[0m
       Macro calls can be nested,  even  with  themselves.   Tracing  recurses
       along with them; this feature can help to detangle complex call stacks.

              $ [1mcat <<EOF | groff -m trace > /dev/null[0m
              [1m.de countdown[0m
              [1m. nop \\$1[0m
              [1m. nr count (\\$1 ‐ 1)[0m
              [1m. if \\n[count] .countdown \\n[count][0m
              [1m..[0m
              [1m.countdown 3[0m
              [1mblastoff[0m
              [1mEOF[0m
               *** .de countdown
               *** de trace enter: .countdown "3"
                *** de trace enter: .countdown "2"
                 *** de trace enter: .countdown "1"
                 *** trace exit: .countdown "1"
                *** trace exit: .countdown "2"
               *** trace exit: .countdown "3"

   [1mTracing with the mso request[0m
       Now  let  us  activate tracing within the document, not with a command‐
       line option.  We might do this when using a macro package  like  [4mms[24m  or
       [4mmom[24m,  where  we  may  not  want to be distracted by traces of macros we
       didn’t write.

              $ [1mcat <<EOF | groff ‐ms > /dev/null[0m
              [1m.LP[0m
              [1mThis is my introductory paragraph.[0m
              [1m.mso trace.tmac[0m
              [1m.de Mymac[0m
              [1m..[0m
              [1m.Mymac[0m
              [1m.PP[0m
              [1mLet us review the existing literature.[0m
              [1mEOF[0m
               *** .de Mymac
               *** de trace enter: .Mymac
               *** trace exit: .Mymac

       As tracing was not yet active when the macros “LP” and  “PP”  were  de‐
       fined (by [4ms.tmac[24m), their calls were not traced; contrast with the macro
       “Mymac”.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/trace.tmac[0m
              implements the package.

[1mAuthors[0m
       [4mtrace.tmac[24m  was  written  by James Clark.  This document was written by
       Bernd Warken ⟨groff-bernd.warken-72@web.de⟩  and  G.  Branden  Robinson
       ⟨g.branden.robinson@gmail.com⟩.

[1mSee also[0m
       [4mGroff:[24m  [4mThe[24m  [4mGNU[24m [4mImplementation[24m [4mof[24m [4mtroff[24m, by Trent A. Fisher and Werner
       Lemberg, is the primary [4mgroff[24m manual.  You can browse it  interactively
       with “info groff”.

       [4mgroff[24m(1)
              gives an overview of the [4mgroff[24m document formatting system.

       [4mtroff[24m(1)
              supplies details of the [1m-m [22mcommand‐line option.

       [4mgroff_tmac[24m(5)
              offers a survey of [4mgroff[24m macro packages.

       [4mgroff[24m(7)
              is a reference manual for the [4mgroff[24m language.

groff 1.23.0                      5 July 2023                   [4mgroff_trace[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mgroff_www[24m(7)           Miscellaneous Information Manual           [4mgroff_www[24m(7)

[1mName[0m
       groff_www - GNU [4mroff[24m macros for authoring web pages

[1mSynopsis[0m
       [1mgroff -m www [22m[[4moption[24m ...] [[4mfile[24m ...]

[1mDescription[0m
       This  manual page describes the GNU [4mwww[24m macro package, which is part of
       the [4mgroff[24m(7) document formatting system.  This macro file is  automati‐
       cally  loaded  by  the default [4mtroffrc[24m file when the formatter (usually
       [4mgroff[24m(1)) is called with either of the options [1m-Thtml [22mor  [1m-Txhtml[22m.   To
       see  hyperlinks  in action, format this man page using one of those op‐
       tions.

       This document is a basic guide; the HTML output  driver  ([4mgrohtml[24m)  re‐
       mains in an alpha state.  It has been included with the distribution to
       encourage testing.

       Here is a summary of the functions found in this macro set.

       .JOBNAME     split output into multiple files
       .HX          automatic heading level cut off
       .BCL         specify colours on a web page
       .BGIMG       specify background image
       .URL         create a URL using two parameters
       .FTP         create an FTP reference
       .MTO         create an HTML email address
       .TAG         generate an HTML name
       .IMG         include an image file
       .PIMG        include PNG image
       .MPIMG       place PNG on the margin and wrap text around it
       .HnS         begin heading
       .HnE         end heading
       .LK          emit automatically collected links.
       .HR          produce a horizontal rule
       .NHR         suppress automatic generation of rules.
       .HTL         only generate HTML title
       .HEAD        add data to <head> block
       .ULS         unorder list begin
       .ULE         unorder list end
       .OLS         ordered list begin
       .OLE         ordered list end
       .DLS         definition list begin
       .DLE         definition list end
       .LI          insert a list item
       .DC          generate a drop capital
       .HTML        pass an HTML raw request to the device driver
       .CDS         code example begin
       .CDE         code example end
       .ALN         place links on left of main text.
       .LNS         start a new two‐column table with links in the left.
       .LNE         end the two‐column table.
       .LINKSTYLE   initialize default URL attributes.

[1mMacros[0m
       [1m.JOBNAME filename[0m
              Split output into multiple HTML files.  A file is split whenever
              a  .SH  or  .NH 1 is encountered.  Its argument is the file stem
              name for future output files.   This  option  is  equivalent  to
              [4mgrohtml[24m’s [1m-j [22moption.

       [1m.HX n  [22mSpecify  the  cut  off  depth when generating links from section
              headings.  For example, a parameter of 2 would cause [4mgrohtml[24m  to
              generate  a list of links for [1m.NH 1 [22mand [1m.NH 2 [22mbut not for [1m.NH 3[22m.
              Whereas

                     .HX 0

              tells [4mgrohtml[24m that no heading links should be  created  at  all.
              Another  method for turning automatic headings off is by issuing
              the command‐line switch [1m-P-l [22mto [4mgroff[24m.

       [1m.BCL [4m[22mforeground[24m [4mbackground[24m [4mactive[24m [4mnot‐visited[24m [4mvisited[0m
              This macro takes five parameters: foreground, background, active
              hypertext link, hypertext link not yet visited, and visited  hy‐
              pertext link colour.

       [1m.BGIMG imagefile[0m
              the only parameter to this macro is the background image file.

       [1m.URL url [description] [after][0m
              generates  a URL using either one, two, or three arguments.  The
              first parameter is the actual URL, the second is the name of the
              link, and the third is optional stuff to be printed  immediately
              afterwards.   If  [1mdescription  [22mand [1mafter [22mare absent then the [1mURL[0m
              becomes the anchor text.  Hyphenation is disabled while printing
              the actual URL; explicit breakpoints should be inserted with the
              [1m\: [22mescape sequence.  Here  is  how  to  encode  foo  ⟨http://foo
              .org/⟩:

                     [1m.URL http://\:foo\:.org/ foo :[0m

              If this is processed by a device other than [1m-Thtml [22mor [1m-Txhtml [22mit
              appears as:

                     foo ⟨http://foo.org⟩:

              The  URL macro can be of any type; for example, we can reference
              Eric Raymond’s [4mpic[24m guide ⟨pic.html⟩ by:

                     [1m.URL pic\:.html "Eric Raymond's pic guide"[0m

       [1m.MTO address [description] [after][0m
              Generate an email HTML reference.  The first argument is  manda‐
              tory  as the email address.  The optional second argument is the
              text you see in your browser.  If an empty  argument  is  given,
              [1maddress  [22mis  used  instead.  An optional third argument is stuff
              printed immediately afterwards.  Hyphenation is  disabled  while
              printing  the actual email address.  For example, Joe User ⟨joe@
              user.org⟩ can be achieved by the following macro:

                     [1m.MTO joe@user.org "Joe User"[0m

              All URLs currently are treated as consuming no textual space  in
              [4mgroff[24m.   This  could be considered as a bug since it causes some
              problems.  To circumvent this,  [1mwww.tmac  [22minserts  a  zero‐width
              character  which  expands  to a harmless space (only if run with
              [1m-Thtml [22mor [1m-Txhtml[22m).

       [1m.FTP url [description] [after][0m
              indicates that data can be obtained via FTP.  The first argument
              is the URL and the second is the browser text.   A  third  argu‐
              ment, similar to the macros above, is intended for stuff printed
              immediately  afterwards.  The second and the third parameter are
              optional.  Hyphenation is disabled  while  printing  the  actual
              URL.   As an example, here is the location of the GNU FTP server
              ⟨ftp://ftp.gnu.org/⟩.  The macro example above can be  specified
              as:

                     [1m.FTP ftp://\:ftp\:.gnu\:.org/ "GNU FTP server" .[0m

       [1m.TAG name[0m
              Generates  an HTML name tag from its argument.  This can then be
              referenced using the URL ⟨#URL⟩ macro.  As you can see, you must
              precede the tag name with [1m# [22msince it is a local reference.  This
              link was achieved via placing  a  TAG  in  the  URL  description
              above; the source looks like this:

                     .TP
                     .B URL
                     generates
                     .TAG URL
                     a URL using either two or three arguments.
                     ...

       [1m.IMG [-R|-L|-C] filename [width] [height][0m
              Include  a picture into the document.  The first argument is the
              horizontal location: right, left, or center  ([1m-R[22m,  [1m-L[22m,  or  [1m-C[22m).
              Alignment  is  centered by default ([1m-C[22m).  The second argument is
              the filename.  The optional third and fourth arguments  are  the
              width and height.  If the width is absent it defaults to 1 inch.
              If  the  height  is  absent it defaults to the width.  This maps
              onto an HTML img tag.  If you are including a PNG image then  it
              is advisable to use the [1mPIMG [22mmacro.

       [1m.PIMG [-R|-L|-C] filename [width [height]][0m
              Include  an  image  in PNG format.  This macro takes exactly the
              same parameters as the [1mIMG [22mmacro; it has the advantage of  work‐
              ing with PostScript and HTML devices also since it can automati‐
              cally convert the image into the EPS format, using the following
              programs  of the [1mnetpbm [22mpackage: [1mpngtopnm[22m, [1mpnmcrop[22m, and [1mpnmtops[22m.
              If the document isn’t processed with [1m-Thtml  [22mor  [1m-Txhtml  [22mit  is
              necessary to use the [1m-U [22moption of [4mgroff[24m.

       [1m.MPIMG [-R|-L] [-G gap] filename [width [height]][0m
              Place  a  PNG  image on the margin and wrap text around it.  The
              first parameters are optional.  The alignment: left or right ([1m-L[0m
              or [1m-R[22m) specifies the margin where the picture is placed at.  The
              default alignment is left ([1m-L[22m).  Optionally, [1m-G [4m[22mgap[24m can be  used
              to  arrange  a  gap  between the picture and the text that wraps
              around it.  The default gap width is zero.
              The first non‐optional argument is the filename.   The  optional
              following  arguments  are the width and height.  If the width is
              absent it defaults to 1 inch.  If the height is  absent  it  de‐
              faults to the width.  Example:

                     .MPIMG -L -G 2c foo.png 3c 1.5c

              The  height  and  width  may  also be given as percentages.  The
              PostScript device calculates the width from the [1m.l [22mregister  and
              the height from the [1m.p [22mregister.  For example:

                     .MPIMG -L -G 2c foo.png 15%

       [1m.HnS n [22mBegin  heading.  The numeric heading level [4mn[24m is specified by the
              first parameter.  Use this macro if your headings  contain  URL,
              FTP or MTO macros.  Example:

                     .HnS 1
                     .HR
                     GNU Troff
                     .URL https://\:www\:.gnu\:.org/\:software/\:groff/
                     \[em]a
                     .URL http://www\:.gnu\:.org/ GNU
                     project.
                     .HR
                     .HnE

              In  this case you might wish to disable automatic links to head‐
              ings.  This can be done via [1m-P-l [22mfrom the command line.

       [1m.HnE   [22mEnd heading.

       [1m.LK    [22mForce [4mgrohtml[24m to place the automatically generated links at this
              position.

       [1m.HR    [22mGenerate a full‐width horizontal rule for  [1m-Thtml  [22mand  [1m-Txhtml[22m.
              No effect for all other devices.

       [1m.NHR   [22mSuppress  generation  of  the top and bottom rules which [4mgrohtml[0m
              emits by default.

       [1m.HTL   [22mGenerate an HTML title only.  This differs from the [1mTL [22mmacro  of
              the  [1mms  [22mmacro package which generates both an HTML title and an
              <H1> heading.  Use it to provide an HTML title as search  engine
              fodder  but  a  graphic title in the document.  The macro termi‐
              nates when a space or break is seen (.sp, .br).

       [1m.HEAD  [22mAdd arbitrary HTML data to the <head>  block.   Ignored  if  not
              processed with [1m-Thtml [22mor [1m-Txhtml[22m.  Example:

                     .HEAD "<link \
                       rel=""icon"" \
                       type=""image/png"" \
                       href=""http://foo.org//bar.png""/>"

       [1m.HTML  [22mAll  text after this macro is treated as raw HTML.  If the docu‐
              ment is processed without [1m-Thtml [22mor [1m-Txhtml [22mthen  the  macro  is
              ignored.  Internally, this macro is used as a building block for
              other higher‐level macros.

              For example, the [1mBGIMG [22mmacro is defined as

                     .de BGIMG
                     .   HTML <body background=\\$1>
                     ..

       [1m.DC l text [color][0m
              Produce a drop capital.  The first parameter is the letter to be
              dropped and enlarged, the second parameter [1mtext [22mis the adjoining
              text  whose  height the first letter should not exceed.  The op‐
              tional third parameter is the color of the dropped  letter.   It
              defaults to black.

       [1m.CDS   [22mStart displaying a code section in constant width font.

       [1m.CDE   [22mEnd code display

       [1m.ALN [color] [percentage][0m
              Place  section  heading  links  automatically to the left of the
              main text.  The color argument is optional and if present  indi‐
              cates which HTML background color is to be used under the links.
              The  optional percentage indicates the amount of width to devote
              to displaying the links.  The default values are #eeeeee and  30
              for color and percentage width, respectively.  This macro should
              only  be  called  once  at the beginning of the document.  After
              calling this macro each section heading emits an HTML table con‐
              sisting of the links in the left and the  section  text  on  the
              right.

       [1m.LNS   [22mStart  a  new  two‐column  table  with links in the left column.
              This can be called if the document has text before the first .SH
              and if .ALN is used.  Typically this is called just  before  the
              first  paragraph  and  after the main title as it indicates that
              text after this point should be positioned to the right  of  the
              left‐hand navigational links.

       [1m.LNE   [22mEnd a two‐column table.  This should be called at the end of the
              document if .ALN was used.

       [1m.LINKSTYLE color [ fontstyle [ openglyph closeglyph ] ][0m
              Initialize  default  URL attributes to be used if this macro set
              is not used with the HTML device.  The macro set initializes it‐
              self with the following call

                     .LINKSTYLE blue CR \[la] \[ra]

              but these values will be superseded by a user call to LINKSTYLE.

[1mSection heading links[0m
       By default [4mgrohtml[24m generates links to all section headings  and  places
       these at the top of the HTML document.  (See LINKS ⟨#LK⟩ for details of
       how to switch this off or alter the position).

[1mLimitations of [4mgrohtml[0m
       [4mtbl[24m(1)  tables are rendered as PNG images.  Paul DuBois’s approach with
       [4mtblcvt[24m(1), part of  the  [4mtroffcvt[24m  distribution  ⟨http://www.snake.net/
       software/troffcvt/⟩, should be explored.

[1mFiles[0m
       [4m/usr/share/groff/1.23.0/tmac/www.tmac[0m

[1mAuthors[0m
       The  [4mwww[24m  macro package was written by Gaius Mulley ⟨gaius@glam.ac.uk⟩,
       with  additions  by  Werner  Lemberg  ⟨wl@gnu.org⟩  and  Bernd   Warken
       ⟨groff-bernd.warken-72@web.de⟩.

[1mSee also[0m
       [4mgroff[24m(1), [4mtroff[24m(1), [4mgrohtml[24m(1), [4mnetpbm[24m(1)

groff 1.23.0                      5 July 2023                     [4mgroff_www[24m(7)
───────────────────────────────────────────────────────────────────────────────
[4mroff[24m(7)                Miscellaneous Information Manual                [4mroff[24m(7)

[1mName[0m
       roff - concepts and history of [4mroff[24m typesetting

[1mDescription[0m
       The  term [4mroff[24m denotes a family of document formatting systems known by
       names like [4mtroff[24m, [4mnroff[24m, and [4mditroff[24m.  A [4mroff[24m system consists of an in‐
       terpreter for an extensible text formatting language and a set of  pro‐
       grams for preparing output for various devices and file formats.  Unix‐
       like  operating  systems  often  distribute  a [4mroff[24m system.  The manual
       pages on Unix systems (“man pages”) and bestselling books  on  software
       engineering,  including Brian Kernighan and Dennis Ritchie’s [4mThe[24m [4mC[24m [4mPro‐[0m
       [4mgramming[24m [4mLanguage[24m and W. Richard Stevens’s [4mAdvanced[24m [4mProgramming[24m [4min[24m  [4mthe[0m
       [4mUnix[24m [4mEnvironment[24m have been written using [4mroff[24m systems.  GNU [4mroff[24m—[4mgroff[24m—
       is arguably the most widespread [4mroff[24m implementation.

       Below we present typographical concepts that form the background of all
       [4mroff[24m implementations, narrate the development history of some [4mroff[24m sys‐
       tems,  detail the command pipeline managed by [4mgroff[24m(1), survey the for‐
       matting language, suggest tips for editing [4mroff[24m  input,  and  recommend
       further reading materials.

[1mConcepts[0m
       [4mroff[24m input files contain text interspersed with instructions to control
       the  formatter.   Even in the absence of such instructions, a [4mroff[24m for‐
       matter still processes its input in several ways, by filling, hyphenat‐
       ing, breaking, and adjusting it, and supplementing it  with  inter‐sen‐
       tence space.  These processes are basic to typesetting, and can be con‐
       trolled at the input document’s discretion.

       When a device‐independent [4mroff[24m formatter starts up, it obtains informa‐
       tion  about  the  device for which it is preparing output from the lat‐
       ter’s description file (see [4mgroff_font[24m(5)).  An essential  property  is
       the length of the output line, such as “6.5 inches”.

       The  formatter interprets plain text files employing the Unix line‐end‐
       ing convention.  It reads input a character at a time, collecting words
       as it goes, and fits as many words together on an  output  line  as  it
       can—this is known as [4mfilling.[24m  To a [4mroff[24m system, a [4mword[24m is any sequence
       of  one  or more characters that aren’t spaces or newlines.  The excep‐
       tions separate words.

       A [4mroff[24m formatter attempts to detect boundaries between  sentences,  and
       supplies  additional  inter‐sentence space between them.  It flags cer‐
       tain characters (normally “[1m![22m”, “[1m?[22m”, and “[1m.[22m”) as  potentially  ending  a
       sentence.   When  the formatter encounters one of these [4mend‐of‐sentence[0m
       [4mcharacters[24m at the end of an input line, or one of them is  followed  by
       two (unescaped) spaces on the same input line, it appends an inter‐word
       space  followed  by  an  inter‐sentence space in the output.  The dummy
       character escape sequence [1m\& [22mcan be used after an end‐of‐sentence char‐
       acter to defeat end‐of‐sentence  detection  on  a  per‐instance  basis.
       Normally, the occurrence of a visible non‐end‐of‐sentence character (as
       opposed to a space or tab) immediately after an end‐of‐sentence charac‐
       ter cancels detection of the end of a sentence.  However, several char‐
       acters are treated [4mtransparently[24m after the occurrence of an end‐of‐sen‐
       tence  character.   That is, a [4mroff[24m does not cancel end‐of‐sentence de‐
       tection when it processes them.  This is because  such  characters  are
       often  used  as footnote markers or to close quotations and parentheti‐
       cals.  The default set is [1m"[22m, [1m'[22m, [1m)[22m,  [1m][22m,  [1m*[22m,  [1m\[dg][22m,  [1m\[dd][22m,  [1m\[rq][22m,  and
       [1m\[cq][22m.   The  last  four are examples of [4mspecial[24m [4mcharacters,[24m escape se‐
       quences whose purpose is to obtain glyphs that are not easily typed  at
       the keyboard, or which have special meaning to the formatter (like [1m\[22m).

       When  an  output  line is nearly full, it is uncommon for the next word
       collected from the input to exactly fill it—typically,  there  is  room
       left  over  only for part of the next word.  The process of splitting a
       word so that it appears partially on one line (with a hyphen  to  indi‐
       cate to the reader that the word has been broken) with its remainder on
       the next is [4mhyphenation.[24m  Hyphenation points can be manually specified;
       [4mgroff[24m  also  uses a hyphenation algorithm and language‐specific pattern
       files to decide which words can be hyphenated and  where.   Hyphenation
       does  not always occur even when the hyphenation rules for a word allow
       it; it can be disabled, and when not disabled there are several parame‐
       ters that can prevent it in certain circumstances.

       Once an output line is full, the next word (or remainder of  a  hyphen‐
       ated one) is placed on a different output line; this is called a [4mbreak.[0m
       In  this  document  and in [4mroff[24m discussions generally, a “break” if not
       further qualified always refers to the termination of an  output  line.
       When  the formatter is filling text, it introduces breaks automatically
       to keep output lines from exceeding the configured line length.   After
       an  automatic  break,  a  [4mroff[24m formatter [4madjusts[24m the line if applicable
       (see below), and then resumes collecting and filling text on  the  next
       output line.

       Sometimes,  a  line  cannot be broken automatically.  This usually does
       not happen with natural language text unless the output line length has
       been manipulated to be extremely short, but  it  can  with  specialized
       text  like  program source code.  [4mgroff[24m provides a means of telling the
       formatter where the line may be broken without hyphens.  This  is  done
       with the non‐printing break point escape sequence [1m\:[22m.

       There  are  several ways to cause a break at a predictable location.  A
       blank input line not only causes a break, but by default it  also  out‐
       puts  a  one‐line  vertical  space  (effectively  a blank output line).
       Macro packages may discourage or disable this “blank  line  method”  of
       paragraphing in favor of their own macros.  A line that begins with one
       or  more spaces causes a break.  The spaces are output at the beginning
       of the next line without being  [4madjusted[24m  (see  below).   Again,  macro
       packages  may  provide  other methods of producing indented paragraphs.
       Trailing spaces on [4mtext[24m [4mlines[24m (see below) are discarded.   The  end  of
       input causes a break.

       After the formatter performs an automatic break, it may then [4madjust[24m the
       line,  widening inter‐word spaces until the text reaches the right mar‐
       gin.  Extra spaces between words are preserved.  Leading  and  trailing
       spaces  are handled as noted above.  Text can be aligned to the left or
       right margin only, or centered, using [4mrequests.[0m

       A [4mroff[24m formatter translates horizontal tab characters, also called sim‐
       ply “tabs”, in the input into movements to the next  tab  stop.   These
       tab stops are by default located every half inch measured from the cur‐
       rent position on the input line.  With them, simple tables can be made.
       However, this method can be deceptive, as the appearance (and width) of
       the  text  in  an  editor  and  the results from the formatter can vary
       greatly, particularly when proportional  typefaces  are  used.   A  tab
       character does not cause a break and therefore does not interrupt fill‐
       ing.   The formatter provides facilities for sophisticated table compo‐
       sition; there are many details  to  track  when  using  the  “tab”  and
       “field” low‐level features, so most users turn to the [4mtbl[24m(1) preproces‐
       sor to lay out tables.

   [1mRequests and macros[0m
       A  [4mrequest[24m  is an instruction to the formatter that occurs after a [4mcon‐[0m
       [4mtrol[24m [4mcharacter,[24m which is recognized at the beginning of an input  line.
       The  regular  control character is a dot “[1m.[22m”.  Its counterpart, the [4mno‐[0m
       [4mbreak[24m [4mcontrol[24m [4mcharacter,[24m a neutral apostrophe “[1m'[22m”, suppresses the break
       implied by some requests.  These characters were chosen because  it  is
       uncommon for lines of text in natural languages to begin with them.  If
       you  require a formatted period or apostrophe (closing single quotation
       mark) where the formatter is expecting a control character, prefix  the
       dot  or  neutral  apostrophe  with the dummy character escape sequence,
       “[1m\&[22m”.

       An input line beginning with a control character is  called  a  [4mcontrol[0m
       [4mline.[24m  Every line of input that is not a control line is a [4mtext[24m [4mline.[0m

       Requests  often  take [4marguments,[24m words (separated from the request name
       and each other by spaces) that specify details of the action  the  for‐
       matter is expected to perform.  If a request is meaningless without ar‐
       guments,  it  is typically ignored.  Of key importance are the requests
       that define macros.  Macros are invoked like requests, enabling the re‐
       quest repertoire to be extended or overridden.

       A [4mmacro[24m can be thought of as an abbreviation you can define for a  col‐
       lection  of control and text lines.  When the macro is [4mcalled[24m by giving
       its name after a control character, it is replaced with what it  stands
       for.   The  process  of  textual replacement is known as [4minterpolation.[0m
       Interpolations are handled as soon as they  are  recognized,  and  once
       performed, a [4mroff[24m formatter scans the replacement for further requests,
       macro calls, and escape sequences.

       In [4mroff[24m systems, the “[1mde[22m” request defines a macro.

   [1mPage geometry[0m
       [4mroff[24m  systems  format  text under certain assumptions about the size of
       the output medium, or page.  For the formatter  to  correctly  break  a
       line it is filling, it must know the line length, which it derives from
       the  page  width.   For it to decide whether to write an output line to
       the current page or wait until the next one,  it  must  know  the  page
       length.   A device’s [4mresolution[24m converts practical units like inches or
       centimeters to [4mbasic[24m [4munits,[24m a convenient length measure for the  output
       device or file format.  The formatter and output driver use basic units
       to  reckon  page measurements.  The device description file defines its
       resolution and page dimensions (see [4mgroff_font[24m(5)).

       A [4mpage[24m is a two‐dimensional structure upon which a [4mroff[24m system  imposes
       a  rectangular coordinate system with its upper left corner as the ori‐
       gin.  Coordinate values are in basic units and increase down and to the
       right.  Useful ones are therefore always positive  and  within  numeric
       ranges corresponding to the page boundaries.

       While  the  formatter (and, later, output driver) is processing a page,
       it keeps track of its [4mdrawing[24m [4mposition,[24m which is the location at  which
       the next glyph will be written, from which the next motion will be mea‐
       sured,  or  where  a geometric object will commence rendering.  Notion‐
       ally, glyphs are drawn from the text baseline upward and to the  right.
       ([4mgroff[24m  does not yet support right‐to‐left scripts.)  The [4mtext[24m [4mbaseline[0m
       is a (usually invisible) line upon which the glyphs of a  typeface  are
       aligned.   A  glyph  therefore  “starts” at its bottom‐left corner.  If
       drawn at the origin, a typical letter  glyph  would  lie  partially  or
       wholly  off the page, depending on whether, like “g”, it features a de‐
       scender below the baseline.

       Such a situation is nearly always undesirable.  It is furthermore  con‐
       ventional  not  to  write  or  draw  at  the extreme edges of the page.
       Therefore the initial drawing position of a [4mroff[24m formatter  is  not  at
       the  origin,  but  below  and to the right of it.  This rightward shift
       from the left edge is known as the [4mpage[24m [4moffset.[24m  ([4mgroff[24m’s terminal out‐
       put devices have page offsets of zero.)  The downward shift leaves room
       for a text output line.

       Text is arranged on a one‐dimensional lattice of  text  baselines  from
       the  top  to  the bottom of the page.  [4mVertical[24m [4mspacing[24m is the distance
       between adjacent text baselines.  Typographic tradition sets this quan‐
       tity to 120% of the type size.  The initial vertical  drawing  position
       is  one unit of vertical spacing below the page top.  Typographers term
       this unit a [4mvee.[0m

       Vertical spacing has an impact on page‐breaking decisions.   Generally,
       when  a  break  occurs, the formatter moves the drawing position to the
       next text baseline automatically.  If the formatter were already  writ‐
       ing  to  the last line that would fit on the page, advancing by one vee
       would place the next text baseline off the page.  Rather than let  that
       happen,  [4mroff[24m  formatters instruct the output driver to eject the page,
       start a new one, and again set the drawing position to  one  vee  below
       the page top; this is a [4mpage[24m [4mbreak.[0m

       When  the  last  line of input text corresponds to the last output line
       that fits on the page, the break caused by the end of input  will  also
       break  the  page,  producing  a useless blank one.  Macro packages keep
       users from having to confront this difficulty by setting “traps”; more‐
       over, all but the simplest page layouts tend to have headers and  foot‐
       ers, or at least bear vertical margins larger than one vee.

   [1mOther language elements[0m
       [4mEscape[24m  [4msequences[24m  start  with the [4mescape[24m [4mcharacter,[24m a backslash [1m\[22m, and
       are followed by at least one additional  character.   They  can  appear
       anywhere in the input.

       With  requests,  the escape and control characters can be changed; fur‐
       ther, escape sequence recognition can be turned off and back on.

       [4mStrings[24m store character sequences.  In [4mgroff[24m, they can be parameterized
       as macros can.

       [4mRegisters[24m store numerical values, including measurements.   The  latter
       are  generally in basic units; [4mscaling[24m [4munits[24m can be appended to numeric
       expressions to clarify their meaning when stored or interpolated.  Some
       read‐only predefined registers interpolate text.

       [4mFonts[24m are identified either by a name or by a mounting position (a non‐
       negative number).  Four styles are available on all devices.  [1mR [22mis “ro‐
       man”: normal, upright text.  [1mB [22mis [1mbold[22m,  an  upright  typeface  with  a
       heavier weight.  [1mI [22mis [4mitalic[24m, a face that is oblique on typesetter out‐
       put  devices and usually underlined instead on terminal devices.  [1mBI [22mis
       [4m[1mbold‐italic[24m[22m, combining both of the foregoing style  variations.   Type‐
       setting  devices  group  these four styles into [4mfamilies[24m of text fonts;
       they also typically offer one or more [4mspecial[24m fonts  that  provide  un‐
       styled glyphs; see [4mgroff_char[24m(7).

       [4mgroff[24m  supports named [4mcolors[24m for glyph rendering and drawing of geomet‐
       ric objects.  Stroke and fill colors are distinct; the stroke color  is
       used for glyphs.

       [4mGlyphs[24m  are  visual  representation forms of [4mcharacters.[24m  In [4mgroff,[24m the
       distinction between those two elements is not  always  obvious  (and  a
       full  discussion  is  beyond  our scope).  In brief, “A” is a character
       when we consider it in the abstract: to make it a glyph, we must select
       a typeface with which to render it, and determine  its  type  size  and
       color.   The  formatting  process  turns  input  characters into output
       glyphs.  A few characters commonly seen on keyboards are  treated  spe‐
       cially  by the [4mroff[24m language and may not look correct in output if used
       unthinkingly; they are the (double) quotation  mark  ([1m"[22m),  the  neutral
       apostrophe  ([1m'[22m),  the  minus  sign ([1m-[22m), the backslash ([1m\[22m), the caret or
       circumflex accent ([1m^[22m), the grave accent ([1m`[22m), and the tilde ([1m~[22m).  All of
       these and more can be produced with [4mspecial[24m [4mcharacter[24m escape sequences;
       see [4mgroff_char[24m(7).

       [4mgroff[24m offers [4mstreams[24m, identifiers for writable files, but for  security
       reasons this feature is disabled by default.

       A  further  few language elements arise as page layouts become more so‐
       phisticated and demanding.  [4mEnvironments[24m collect formatting  parameters
       like line length and typeface.  A [4mdiversion[24m stores formatted output for
       later  use.  A [4mtrap[24m is a condition on the input or output, tested auto‐
       matically by the formatter, that is associated with a macro, calling it
       when that condition is fulfilled.

       Footnote support often exercises all three of the  foregoing  features.
       A simple implementation might work as follows.  A pair of macros is de‐
       fined:  one  starts a footnote and the other ends it.  The author calls
       the first macro where a footnote marker is desired.  The  macro  estab‐
       lishes  a diversion so that the footnote text is collected at the place
       in the body text where its corresponding marker appears.   An  environ‐
       ment  is  created for the footnote so that it is set at a smaller type‐
       face.  The footnote text is formatted in the diversion using that envi‐
       ronment, but it does not yet appear in the output.  The document author
       calls the footnote end macro, which returns to the previous environment
       and ends the diversion.  Later, after much more body text in the  docu‐
       ment,  a  trap,  set a small distance above the page bottom, is sprung.
       The macro called by the trap draws a line across the page and emits the
       stored diversion.  Thus, the footnote is rendered.

[1mHistory[0m
       Computer‐driven document formatting dates back to the 1960s.  The  [4mroff[0m
       system  is intimately connected with Unix, but its origins lie with the
       earlier operating systems CTSS, GECOS, and Multics.

   [1mThe predecessor—[4mRUNOFF[0m
       [4mroff[24m’s ancestor [4mRUNOFF[24m was written in the MAD language by Jerry Saltzer
       to prepare his Ph.D. thesis  on  the  Compatible  Time  Sharing  System
       (CTSS),  a  project of the Massachusetts Institute of Technology (MIT).
       This program is referred to in full capitals, both  to  distinguish  it
       from  its  many  descendants,  and because bits were expensive in those
       days; five‐ and six‐bit character encodings were  still  in  widespread
       usage,  and  mixed‐case  alphabetics  in  file  names seen as a luxury.
       [4mRUNOFF[24m introduced a syntax of inlining formatting directives amid docu‐
       ment text, by beginning a line with a period (an unlikely occurrence in
       human‐readable material) followed by a “control word”.   Control  words
       with obvious meaning like “.line length [4mn[24m” were supported as well as an
       abbreviation system; the latter came to overwhelm the former in popular
       usage  and later derivatives of the program.  A sample of control words
       from a [4mRUNOFF[24m manual of December 1966  ⟨http://web.mit.edu/Saltzer/www/
       publications/ctss/AH.9.01.html⟩ was documented as follows (with the pa‐
       rameter notation slightly altered).  The abbreviations will be familiar
       to [4mroff[24m veterans.

                           Abbreviation   Control word
                                    [1m.ad   [22m.adjust
                                    [1m.bp   [22m.begin page
                                    [1m.br   [22m.break
                                    [1m.ce   [22m.center
                                    [1m.in   [22m.indent [4mn[0m
                                    [1m.ll   [22m.line length [4mn[0m
                                    [1m.nf   [22m.nofill
                                    [1m.pl   [22m.paper length [4mn[0m
                                    [1m.sp   [22m.space [[4mn[24m]

       In  1965, MIT’s Project MAC teamed with Bell Telephone Laboratories and
       General Electric (GE) to inaugurate the Multics  ⟨http://www.multicians
       .org⟩  project.  After a few years, Bell Labs discontinued its partici‐
       pation in Multics, famously prompting the development of  Unix.   Mean‐
       while,  Saltzer’s  [4mRUNOFF[24m proved influential, seeing many ports and de‐
       rivations elsewhere.

       In 1969, Doug McIlroy wrote one such  reimplementation,  adding  exten‐
       sions, in the BCPL language for a GE 645 running GECOS at the Bell Labs
       location  in  Murray Hill, New Jersey.  In its manual, the control com‐
       mands were termed “requests”, their two‐letter  names  were  canonical,
       and  the  control character was configurable with a [1m.cc [22mrequest.  Other
       familiar requests emerged at this time; no‐adjust  ([1m.na[22m),  need  ([1m.ne[22m),
       page  offset  ([1m.po[22m),  tab  configuration ([1m.ta[22m, though it worked differ‐
       ently), temporary indent ([1m.ti[22m), character translation ([1m.tr[22m), and  auto‐
       matic  underlining  ([1m.ul[22m; on [4mRUNOFF[24m you had to backspace and underscore
       in the input yourself).  [1m.fi [22mto enable filling of output lines got  the
       name it retains to this day.  McIlroy’s program also featured a heuris‐
       tic  system  for automatically placing hyphenation points, designed and
       implemented by Molly Wagner.  It furthermore introduced  numeric  vari‐
       ables, termed registers.  By 1971, this program had been ported to Mul‐
       tics and was known as [4mroff[24m, a name McIlroy attributes to Bob Morris, to
       distinguish it from CTSS [4mRUNOFF[24m.

   [1mUnix and [4mroff[0m
       McIlroy’s  [4mroff[24m was one of the first Unix programs.  In Ritchie’s term,
       it was “transliterated” from BCPL to DEC PDP‐7  assembly  language  for
       the fledgling Unix operating system.  Automatic hyphenation was managed
       with  [1m.hc  [22mand  [1m.hy [22mrequests, line spacing control was generalized with
       the [1m.ls [22mrequest, and what later [4mroff[24ms would call diversions were avail‐
       able via “footnote” requests.  This [4mroff[24m  indirectly  funded  operating
       systems  research  at Murray Hill; AT&T prepared patent applications to
       the U.S. government with it.  This arrangement enabled the group to ac‐
       quire a PDP‐11; [4mroff[24m promptly proved equal to the  task  of  formatting
       the  manual  for what would become known as “First Edition Unix”, dated
       November 1971.

       Output from all of the foregoing programs was limited to line  printers
       and  paper  terminals such as the IBM 2471 (based on the Selectric line
       of typewriters) and the Teletype Corporation Model 37.   Proportionally
       spaced type was unavailable.

   [1mNew [4mroff[24m and Typesetter [4mroff[0m
       The first years of Unix were spent in rapid evolution.  The practicali‐
       ties  of preparing standardized documents like patent applications (and
       Unix manual pages), combined with McIlroy’s enthusiasm for  macro  lan‐
       guages,  perhaps created an irresistible pressure to make [4mroff[24m extensi‐
       ble.  Joe Ossanna’s [4mnroff[24m, literally a “new roff”, was the  outlet  for
       this pressure.  By the time of Unix Version 3 (February 1973)—and still
       in  PDP‐11 assembly language—it sported a swath of features now consid‐
       ered essential to [4mroff[24m systems: definition of macros  ([1m.de[22m),  diversion
       of  text  thither ([1m.di[22m), and removal thereof ([1m.rm[22m); trap planting ([1m.wh[22m;
       “when”) and relocation ([1m.ch[22m; “change”); conditional  processing  ([1m.if[22m);
       and  environments  ([1m.ev[22m).  Incremental improvements included assignment
       of the next page number ([1m.pn[22m); no‐space mode ([1m.ns[22m) and  restoration  of
       vertical  spacing  ([1m.rs[22m); the saving ([1m.sv[22m) and output ([1m.os[22m) of vertical
       space; specification of replacement characters for tabs ([1m.tc[22m) and lead‐
       ers ([1m.lc[22m); configuration  of  the  no‐break  control  character  ([1m.c2[22m);
       shorthand  to  disable  automatic  hyphenation ([1m.nh[22m); a condensation of
       what were formerly six different requests  for  configuration  of  page
       “titles”  (headers and footers) into one ([1m.tl[22m) with a length controlled
       separately from the line length ([1m.lt[22m); automatic line numbering  ([1m.nm[22m);
       interactive  input ([1m.rd[22m), which necessitated buffer‐flushing ([1m.fl[22m), and
       was made convenient with early program cessation ([1m.ex[22m); source file in‐
       clusion in its modern form ([1m.so[22m; though [4mRUNOFF[24m had an “.append” control
       word for a similar purpose) and early advance to the next file argument
       ([1m.nx[22m); ignorable content ([1m.ig[22m); and programmable abort ([1m.ab[22m).

       Third Edition Unix also brought the [4mpipe[24m(2) system call, the  explosive
       growth  of a componentized system based around it, and a “filter model”
       that remains perceptible today.  Equally  importantly,  the  Bell  Labs
       site  in  Murray Hill acquired a Graphic Systems C/A/T phototypesetter,
       and with it came the necessity of expanding the capabilities of a  [4mroff[0m
       system  to  cope  with  a variety of proportionally spaced typefaces at
       multiple sizes.  Ossanna wrote a parallel implementation of  [4mnroff[24m  for
       the  C/A/T,  dubbing  it [4mtroff[24m (for “typesetter roff”).  Unfortunately,
       surviving documentation does not illustrate what requests  were  imple‐
       mented  at this time for C/A/T support; the [4mtroff[24m(1) man page in Fourth
       Edition Unix (November 1973) does not feature a  request  list,  unlike
       [4mnroff[24m(1).   Apart from typesetter‐driven features, Unix Version 4 [4mroff[24ms
       added string definitions ([1m.ds[22m); made the escape character  configurable
       ([1m.ec[22m);  and enabled the user to write diagnostics to the standard error
       stream ([1m.tm[22m).  Around 1974, empowered with multiple type  sizes,  ital‐
       ics, and a symbol font specially commissioned by Bell Labs from Graphic
       Systems,  Kernighan  and Lorinda Cherry implemented [4meqn[24m for typesetting
       mathematics.  In the same year, for Fifth Edition  Unix,  Ossanna  com‐
       bined  and reimplemented the two [4mroff[24ms in C, using that language’s pre‐
       processor to generate both from a single source tree.

       Ossanna documented the syntax of the input language to  the  [4mnroff[24m  and
       [4mtroff[24m  programs  in the “Troff User’s Manual”, first published in 1976,
       with further revisions as late as 1992  by  Kernighan.   (The  original
       version  was  entitled “Nroff/Troff User’s Manual”, which may partially
       explain why [4mroff[24m practitioners have tended to refer to it by  its  AT&T
       document  identifier, “CSTR #54”.)  Its final revision serves as the [4mde[0m
       [4mfacto[24m specification of AT&T [4mtroff[24m, and all subsequent  implementors  of
       [4mroff[24m systems have done so in its shadow.

       A  small  and  simple  set of [4mroff[24m macros was first used for the manual
       pages of Unix Version 4 and persisted for two further releases, but the
       first macro package to be formally described and installed  was  [4mms[24m  by
       Michael  Lesk  in Version 6.  He also wrote a manual, “Typing Documents
       on the Unix System”, describing [4mms[24m and basic [4mnroff[24m/[4mtroff[24m usage,  updat‐
       ing it as the package accrued features.  Sixth Edition additionally saw
       the debut of the [4mtbl[24m preprocessor for formatting tables, also by Lesk.

       For  Unix  Version 7 (January 1979), McIlroy designed, implemented, and
       documented the [4mman[24m macro package, introducing most of  the  macros  de‐
       scribed  in  [4mgroff_man[24m(7)  today,  and edited volume 1 of the Version 7
       manual using it.  Documents composed using [4mms[24m  featured  in  volume  2,
       edited by Kernighan.

       Meanwhile,  [4mtroff[24m proved popular even at Unix sites that lacked a C/A/T
       device.  Tom Ferrin of the University of California  at  San  Francisco
       combined  it  with  Allen  Hershey’s  popular  vector  fonts to produce
       [4mvtroff[24m, which translated [4mtroff[24m’s output to the command language used by
       Versatec and Benson‐Varian plotters.

       Ossanna had passed away unexpectedly in 1977, and after the release  of
       Version 7, with the C/A/T typesetter becoming supplanted by alternative
       devices  such  as  the Mergenthaler Linotron 202, Kernighan undertook a
       revision and rewrite of [4mtroff[24m to generalize its design.   To  implement
       this revised architecture, he developed the font and device description
       file  formats  and the page description language that remain in use to‐
       day.  He described these novelties in the article  “A  Typesetter‐inde‐
       pendent TROFF”, last revised in 1982, and like the [4mtroff[24m manual itself,
       it is widely known by a shorthand, “CSTR #97”.

       Kernighan’s innovations prepared [4mtroff[24m well for the introduction of the
       Adobe  PostScript language in 1982 and a vibrant market in laser print‐
       ers with built‐in interpreters for it.   An  output  driver  for  Post‐
       Script, [4mdpost[24m, was swiftly developed.  However, AT&T’s software licens‐
       ing  practices  kept  Ossanna’s  [4mtroff[24m,  with its tight coupling to the
       C/A/T’s capabilities, in parallel distribution with  device‐independent
       [4mtroff[24m  throughout  the  1980s.  Today, however, all actively maintained
       [4mtroff[24ms follow Kernighan’s device‐independent design.

   [4m[1mgroff[24m—a free [4mroff[24m from GNU[0m
       The most important free [4mroff[24m project historically has been  [4mgroff[24m,  the
       GNU  implementation of [4mtroff[24m, developed by James Clark starting in 1989
       and distributed under copyleft ⟨http://www.gnu.org/copyleft⟩  licenses,
       ensuring to all the availability of source code and the freedom to mod‐
       ify  and  redistribute  it, properties unprecedented in [4mroff[24m systems to
       that point.  [4mgroff[24m rapidly attracted contributors, and has served as  a
       replacement  for  almost all applications of AT&T [4mtroff[24m (exceptions in‐
       clude [4mmv[24m, a macro package for preparation of viewgraphs and slides, and
       the [4mideal[24m preprocessor, which produces diagrams from mathematical  con‐
       straints).    Beyond   that,   it  has  added  numerous  features;  see
       [4mgroff_diff[24m(7).  Since its inception and  for  at  least  the  following
       three  decades,  it  has been used by practically all GNU/Linux and BSD
       operating systems.

       [4mgroff[24m continues to be developed, is available for almost all  operating
       systems  in  common use (along with several obscure ones), and is free.
       These factors make [4mgroff[24m the [4mde[24m [4mfacto[24m [4mroff[24m standard today.

   [1mOther free [4mroff[24ms[0m
       In 2007, Caldera/SCO and Sun Microsystems, having  acquired  rights  to
       AT&T  Documenter’s Workbench (DWB) [4mtroff[24m (a descendant of the Bell Labs
       code), released it under a free but GPL‐incompatible license.  This im‐
       plementation ⟨https://github.com/n-t-roff/DWB3.3⟩ was made portable  to
       modern  POSIX  systems, and adopted and enhanced first by Gunnar Ritter
       and  then  Carsten   Kunze   to   produce   Heirloom   Doctools   [4mtroff[0m
       ⟨https://github.com/n‐t‐roff/heirloom‐doctools⟩.

       In  July 2013, Ali Gholami Rudi announced [4mneatroff[24m ⟨https://github.com/
       aligrudi/neatroff⟩, a permissively licensed new implementation.

       Another descendant of DWB [4mtroff[24m is part  of  Plan  9  from  User  Space
       ⟨https://9fans.github.io/plan9port/⟩.   Since 2021, this [4mtroff[24m has been
       available under permissive terms.

[1mUsing [4mroff[0m
       When you read a man page, often a [4mroff[24m is  the  program  rendering  it.
       Some [4mroff[24m implementations provide wrapper programs that make it easy to
       use  the  [4mroff[24m system from the shell’s command line.  These can be spe‐
       cific to a macro package, like [4mmmroff[24m(1), or  more  general.   [4mgroff[24m(1)
       provides  command‐line  options  sparing the user from constructing the
       long, order‐dependent pipelines familiar to AT&T [4mtroff[24m users.  Further,
       a heuristic program, [4mgrog[24m(1), is available to infer from  a  document’s
       contents which [4mgroff[24m arguments should be used to process it.

   [1mThe [4mroff[24m pipeline[0m
       A  typical  [4mroff[24m document is prepared by running one or more processors
       in series, followed by a a formatter program and then an output  driver
       (or  “device  postprocessor”).  Commonly, these programs are structured
       into a pipeline; that is, each is run in sequence such that the  output
       of  one is taken as the input to the next, without passing through sec‐
       ondary storage.  (On non‐Unix systems, pipelines may have to  be  simu‐
       lated with temporary files.)

              $ [4mpreproc1[24m [1m< [4m[22minput‐file[24m [1m| [4m[22mpreproc2[24m [1m| [22m... [1m| troff [22m[[4moption[24m] ... [1m\[0m
                  [1m| [4m[22moutput‐driver[0m

       Once  all preprocessors have run, they deliver pure [4mroff[24m language input
       to the formatter, which in turn generates a document in a page descrip‐
       tion language that is then interpreted by a postprocessor for  viewing,
       printing, or further processing.

       Each  program interprets input in a language that is independent of the
       others; some are purely descriptive, as with [4mtbl[24m(1)  and  [4mroff[24m  output,
       and  some  permit the definition of macros, as with [4meqn[24m(1) and [4mroff[24m in‐
       put.  Most [4mroff[24m input files employ the macros of a document  formatting
       package,  intermixed  with  instructions for one or more preprocessors,
       and seasoned with escape sequences and requests from the [4mroff[24m language.
       Some documents are simpler still, since their formatting packages  dis‐
       courage direct use of [4mroff[24m requests; man pages are a prominent example.
       Many features of the [4mroff[24m language are seldom needed by users; only au‐
       thors of macro packages require a substantial command of them.

   [1mPreprocessors[0m
       A  [4mroff[24m  preprocessor is a program that, directly or ultimately, gener‐
       ates output in the [4mroff[24m language.  Typically, each preprocessor defines
       a language of its own that transforms its input into that for  [4mroff[24m  or
       another  preprocessor.   As an example of the latter, [4mchem[24m produces [4mpic[0m
       input.  Preprocessors must consequently be run in an appropriate order;
       [4mgroff[24m(1) handles this automatically for all preprocessors  supplied  by
       the GNU [4mroff[24m system.

       Portions  of the document written in preprocessor languages are usually
       bracketed by tokens that look like [4mroff[24m macro calls.  [4mroff[24m preprocessor
       programs transform only the regions of the document intended for  them.
       When  a  preprocessor language is used by a document, its corresponding
       program must process it before the input is seen by the  formatter,  or
       incorrect rendering is almost guaranteed.

       GNU  [4mroff[24m provides several preprocessors, including [4meqn[24m, [4mgrn[24m, [4mpic[24m, [4mtbl[24m,
       [4mrefer[24m, and [4msoelim[24m.  See [4mgroff[24m(1) for a complete list.  Other preproces‐
       sors for [4mroff[24m systems are known.

              [4mdformat[24m   depicts data structures;
              [4mgrap[24m      constructs statistical charts; and
              [4mideal[24m     draws diagrams using a constraint‐based language.

   [1mFormatter programs[0m
       A [4mroff[24m formatter transforms [4mroff[24m language input into a single file in a
       page description language, described in [4mgroff_out[24m(5), intended for pro‐
       cessing by a selected device.  This page description language  is  spe‐
       cialized  in  its  parameters, but not its syntax, for the selected de‐
       vice; the format is device‐[4mindependent[24m, but not  device‐[4magnostic[24m.   The
       parameters the formatter uses to arrange the document are stored in [4mde‐[0m
       [4mvice[24m and [4mfont[24m [4mdescription[24m [4mfiles[24m; see [4mgroff_font[24m(5).

       AT&T  Unix  had two formatters—[4mnroff[24m for terminals, and [4mtroff[24m for type‐
       setters.  Often, the name [4mtroff[24m is used loosely to refer to both.  When
       generalizing thus, [4mgroff[24m documentation prefers the term “[4mroff[24m”.  In GNU
       [4mroff[24m, the formatter program is always [4mtroff[24m(1).

   [1mDevices and output drivers[0m
       To a [4mroff[24m system, a [4mdevice[24m is a hardware interface like  a  printer,  a
       text  or  graphical  terminal, or a standardized file format that unre‐
       lated software can interpret.  An  [4moutput[24m  [4mdriver[24m  is  a  program  that
       parses  the  output  of [4mtroff[24m and produces instructions specific to the
       device or file format it supports.  An output driver might support mul‐
       tiple devices, particularly if they are similar.

       The names of the devices and their driver programs  are  not  standard‐
       ized.   Technological  fashions  evolve;  the devices used for document
       preparation when AT&T [4mtroff[24m was first  written  in  the  1970s  are  no
       longer  used  in  production  environments.   Device  capabilities have
       tended to increase,  improving  resolution  and  font  repertoire,  and
       adding color output and hyperlinking.  Further, to reduce file size and
       processing time, AT&T [4mtroff[24m’s page description language placed low lim‐
       its on the magnitudes of some quantities it could represent.  Its Post‐
       Script output driver, [4mdpost[24m(1), had a resolution of 720 units per inch;
       [4mgroff[24m’s [4mgrops[24m(1) uses 72,000.

[4m[1mroff[24m programming[0m
       Documents  using  [4mroff[24m are normal text files interleaved with [4mroff[24m for‐
       matting elements.  The [4mroff[24m language is powerful enough to support  ar‐
       bitrary  computation  and  it supplies facilities that encourage exten‐
       sion.  The primary such facility is macro definition;  with  this  fea‐
       ture, macro packages have been developed that are tailored for particu‐
       lar applications.

   [1mMacro packages[0m
       Macro  packages  can  have  a much smaller vocabulary than [4mroff[24m itself;
       this trait combined with their domain‐specific  nature  can  make  them
       easy  to  acquire  and  master.  The macro definitions of a package are
       typically kept in a file called  [4mname[24m[1m.tmac  [22m(historically,  [1mtmac.[4m[22mname[24m).
       Find  details  on  the  naming  and  placement  of  macro  packages  in
       [4mgroff_tmac[24m(5).

       A macro package anticipated for use in a document can  be  declared  to
       the  formatter by the command‐line option [1m-m[22m; see [4mtroff[24m(1).  It can al‐
       ternatively be specified within a document using the [1mmso [22mrequest of the
       [4mgroff[24m language; see [4mgroff[24m(7).

       Well‐known macro packages include [4mman[24m for  traditional  man  pages  and
       [4mmdoc[24m for BSD‐style manual pages.  Macro packages for typesetting books,
       articles,  and letters include [4mms[24m (from “manuscript macros”), [4mme[24m (named
       by a system administrator from the first name of its creator, Eric All‐
       man), [4mmm[24m (from “memorandum macros”), and [4mmom[24m, a punningly named package
       exercising many [4mgroff[24m extensions.  See [4mgroff_tmac[24m(5) for more.

   [1mThe [4mroff[24m formatting language[0m
       The [4mroff[24m language provides requests, escape sequences, macro definition
       facilities, string variables, registers for storage of numbers  or  di‐
       mensions, and control of execution flow.  The theoretically minded will
       observe that a [4mroff[24m is not a mere markup language, but Turing‐complete.
       It has storage (registers), it can perform tests (as in conditional ex‐
       pressions like “[1m(\n[i] >= 1)[22m”), its “[1mif[22m” and related requests alter the
       flow of control, and macro definition permits unbounded recursion.

       [4mRequests[24m and [4mescape[24m [4msequences[24m are instructions, predefined parts of the
       language, that perform formatting operations, interpolate stored mater‐
       ial,  or otherwise change the state of the parser.  The user can define
       their own request‐like elements by composing together  text,  requests,
       and  escape sequences [4mad[24m [4mlibitum.[24m  A document writer will not (usually)
       note any difference in usage for requests or macros; both are found  on
       control lines.  However, there is a distinction; requests take either a
       fixed  number  of arguments (sometimes zero), silently ignoring any ex‐
       cess, or consume the rest of the input line, whereas macros can take  a
       variable number of arguments.  Since arguments are separated by spaces,
       macros  require  a  means of embedding a space in an argument; in other
       words, of quoting it.  This then demands a mechanism of  embedding  the
       quoting character itself, in case [4mit[24m is needed literally in a macro ar‐
       gument.  AT&T [4mtroff[24m had complex rules involving the placement and repe‐
       tition  of the double quote to achieve both aims.  [4mgroff[24m cuts this knot
       by supporting a special character escape sequence for the neutral  dou‐
       ble  quote,  “[1m\[dq][22m”,  which  never performs quoting in the typesetting
       language, but is simply a glyph, ‘[1m"[22m’.

       [4mEscape[24m [4msequences[24m start with a backslash, “[1m\[22m”.  They can  appear  almost
       anywhere,  even  in  the midst of text on a line, and implement various
       features, including the insertion of special characters with “[1m\([4mxx[24m[22m”  or
       “[1m\[[4mxxx[24m][22m”,  break  suppression  at  input  line  endings with “[1m\c[22m”, font
       changes with “[1m\f[22m”, type size changes with “[1m\s[22m”, in‐line  comments  with
       “[1m\"[22m”, and many others.

       [4mStrings[24m  store text.  They are populated with the [1mds [22mrequest and inter‐
       polated using the [1m\* [22mescape sequence.

       [4mRegisters[24m store numbers and measurements.  A register can be  set  with
       the  request  [1mnr  [22mand its value can be retrieved by the escape sequence
       [1m\n[22m.

[1mFile naming conventions[0m
       The structure or content of a file name, beyond  its  location  in  the
       file  system, is not significant to [4mroff[24m tools.  [4mroff[24m documents employ‐
       ing “full‐service” macro packages (see [4mgroff_tmac[24m(5)) tend to be  named
       with a suffix identifying the package; we thus see file names ending in
       [4m.man[24m, [4m.ms[24m, [4m.me[24m, [4m.mm[24m, and [4m.mom[24m, for instance.  When installed, man pages
       tend  to  be named with the manual’s section number as the suffix.  For
       example, the file name for this document is [4mroff.7[24m.  Practice for “raw”
       [4mroff[24m documents is less consistent; they are sometimes seen  with  a  [4m.t[0m
       suffix.

[1mInput conventions[0m
       Since [4mtroff[24m fills text automatically, it is common practice in the [4mroff[0m
       language  to  avoid  visual composition of text in input files: the es‐
       thetic appeal of the formatted output is what matters.  Therefore, [4mroff[0m
       input should be arranged such that it is easy for authors and maintain‐
       ers to compose and develop the document, understand the syntax of  [4mroff[0m
       requests, macro calls, and preprocessor languages used, and predict the
       behavior  of the formatter.  Several traditions have accrued in service
       of these goals.

       • Follow sentence endings in the input  with  newlines  to  ease  their
         recognition.   It  is  frequently  convenient to end text lines after
         colons and semicolons as well, as these typically precede independent
         clauses.  Consider doing so after commas; they often occur  in  lists
         that become easy to scan when itemized by line, or constitute supple‐
         ments  to the sentence that are added, deleted, or updated to clarify
         it.  Parenthetical and quoted phrases are also  good  candidates  for
         placement on text lines by themselves.

       • Set your text editor’s line length to 72 characters or fewer; see the
         subsections  below.   This  limit, combined with the previous item of
         advice, makes it less common that an input line  will  wrap  in  your
         text  editor,  and  thus will help you perceive excessively long con‐
         structions in your text.  Recall that natural languages originate  in
         speech,  not  writing, and that punctuation is correlated with pauses
         for breathing and changes in prosody.

       • Use [1m\& [22mafter “[1m![22m”, “[1m?[22m”, and “[1m.[22m” if they are followed by space, tab, or
         newline characters and don’t end a sentence.

       • In filled text lines, use [1m\& [22mbefore “[1m.[22m” and “[1m'[22m” if they are  preceded
         by  space, so that reflowing the input doesn’t turn them into control
         lines.

       • Do not use spaces to perform indentation or align columns of a table.
         Leading spaces are reliable when text is not being filled.

       • Comment your document.  It is never too soon  to  apply  comments  to
         record  information  of use to future document maintainers (including
         your future self).  The [1m\" [22mescape sequence causes [4mtroff[24m to ignore the
         remainder of the input line.

       • Use the empty request—a control character followed immediately  by  a
         newline—to  visually  manage  separation  of material in input files.
         Many of the [4mgroff[24m project’s own documents use an  empty  request  be‐
         tween  sentences,  after  macro definitions, and where a break is ex‐
         pected, and two empty requests between paragraphs or  other  requests
         or  macro calls that will introduce vertical space into the document.
         You can combine the empty request with the comment escape sequence to
         include whole‐line comments in your document, and even “comment  out”
         sections of it.

       An  example  sufficiently  long to illustrate most of the above sugges‐
       tions in practice follows.  An arrow → indicates a tab character.

              .\"   nroff this_file.roff | less
              .\"   groff -T ps this_file.roff > this_file.ps
              →The theory of relativity is intimately connected with
              the theory of space and time.
              .
              I shall therefore begin with a brief investigation of
              the origin of our ideas of space and time,
              although in doing so I know that I introduce a
              controversial subject.  \" remainder of paragraph elided
              .
              .

              →The experiences of an individual appear to us arranged
              in a series of events;
              in this series the single events which we remember
              appear to be ordered according to the criterion of
              \[lq]earlier\[rq] and \[lq]later\[rq], \" punct swapped
              which cannot be analysed further.
              .
              There exists,
              therefore,
              for the individual,
              an I-time,
              or subjective time.
              .
              This itself is not measurable.
              .
              I can,
              indeed,
              associate numbers with the events,
              in such a way that the greater number is associated with
              the later event than with an earlier one;
              but the nature of this association may be quite
              arbitrary.
              .
              This association I can define by means of a clock by
              comparing the order of events furnished by the clock
              with the order of a given series of events.
              .
              We understand by a clock something which provides a
              series of events which can be counted,
              and which has other properties of which we shall speak
              later.
              .\" Albert Einstein, _The Meaning of Relativity_, 1922

   [1mEditing with Emacs[0m
       Official GNU doctrine holds that the best program for  editing  a  [4mroff[0m
       document  is Emacs; see [4memacs[24m(1).  It provides an [4mnroff[24m major mode that
       is suitable for all kinds of [4mroff[24m dialects.  This mode can be activated
       by the following methods.

       When editing a file within Emacs the mode can be changed by typing “[4mM‐x[0m
       [1mnroff-mode[22m”, where [4mM‐x[24m means to hold down the meta key (often  labelled
       “Alt”) while pressing and releasing the “x” key.

       It is also possible to have the mode automatically selected when a [4mroff[0m
       file is loaded into the editor.

       • The most general method is to include file‐local variables at the end
         of the file; we can also configure the fill column this way.

                .\" Local Variables:
                .\" fill-column: 72
                .\" mode: nroff
                .\" End:

       • Certain  file  name  extensions,  such  as those commonly used by man
         pages, trigger the automatic activation of the [4mnroff[24m mode.

       • Technically, having the sequence

                .\" -*- nroff -*-

         in the first line of a file will cause Emacs to enter the [4mnroff[24m major
         mode when it is loaded into the buffer.  Unfortunately,  some  imple‐
         mentations of the [4mman[24m(1) program are confused by this practice, so we
         discourage it.

   [1mEditing with Vim[0m
       Other editors provide support for [4mroff[24m‐style files too, such as [4mvim[24m(1),
       an  extension  of the [4mvi[24m(1) program.  Vim’s highlighting can be made to
       recognize [4mroff[24m files by setting the [1mfiletype [22moption in a Vim  [4mmodeline[24m.
       For  this  feature to work, your copy of [4mvim[24m must be built with support
       for, and configured to enable, several features; consult  the  editor’s
       online  help topics “auto-setting”, “filetype”, and “syntax”.  Then put
       the following at the end of your [4mroff[24m files, after any Emacs configura‐
       tion:

                     .\" vim: set filetype=groff textwidth=72:

       Replace “groff” in the above with “nroff” if you want highlighting that
       does [4mnot[24m recognize many of the GNU extensions to [4mroff[24m, such as request,
       register, and string names longer than two characters.

[1mAuthors[0m
       This document was written by  Bernd  Warken  ⟨groff-bernd.warken-72@web
       .de⟩ and G. Branden Robinson ⟨g.branden.robinson@gmail.com⟩.

[1mSee also[0m
       Much  [4mroff[24m documentation is available.  The Bell Labs papers describing
       AT&T [4mtroff[24m remain available, and [4mgroff[24m is documented comprehensively.

   [1mInternet sites[0m
       [4mUnix[24m       [4mText[24m       [4mProcessing[24m       ⟨https://github.com/larrykollar/
       Unix-Text-Processing⟩, by Dale Dougherty and Tim O’Reilly, 1987, Hayden
       Books.   This  well‐regarded  text brings the reader from a state of no
       knowledge of Unix or text editing (if necessary) to sophisticated  com‐
       puter‐aided  typesetting.  It has been placed under a free software li‐
       cense by its authors and updated by a team of  [4mgroff[24m  contributors  and
       enthusiasts.

       “History  of  Unix  Manpages” ⟨http://manpages.bsd.lv/history.html⟩, an
       online article maintained by the mdocml project, provides  an  overview
       of [4mroff[24m development from Saltzer’s [4mRUNOFF[24m to 2008, with links to origi‐
       nal  documentation and recollections of the authors and their contempo‐
       raries.

       troff.org ⟨http://www.troff.org/⟩, Ralph Corderoy’s  [4mtroff[24m  site,  pro‐
       vides an overview and pointers to much historical [4mroff[24m information.

       Multicians ⟨http://www.multicians.org/⟩, a site by Multics enthusiasts,
       contains a lot of information on the MIT projects CTSS and Multics, in‐
       cluding  [4mRUNOFF[24m;  it is especially useful for its glossary and the many
       links to historical documents.

       The Unix Archive ⟨http://www.tuhs.org/Archive/⟩, curated  by  the  Unix
       Heritage Society, provides the source code and some binaries of histor‐
       ical  Unices  (including  the source code of some versions of [4mtroff[24m and
       its documentation) contributed by their copyright holders.

       Jerry Saltzer’s home page ⟨http://web.mit.edu/Saltzer/www/publications/
       pubs.html⟩ stores some documents using the original  [4mRUNOFF[24m  formatting
       language.

       [4mgroff[24m  ⟨http://www.gnu.org/software/groff⟩,  GNU  [4mroff[24m’s web site, pro‐
       vides convenient access to [4mgroff[24m’s source code repository, bug tracker,
       and mailing lists (including archives and the subscription interface).

   [1mHistorical [4mroff[24m documentation[0m
       Many AT&T [4mtroff[24m documents are available online, and  can  be  found  at
       Ralph Corderoy’s site (see above) or via Internet search.

       Of  foremost significance are two mentioned in section “History” above,
       describing the language and its device‐independent implementation,  re‐
       spectively.

       “Troff  User’s  Manual” by Joseph F. Ossanna, 1976 (revised by Brian W.
       Kernighan, 1992), AT&T Bell Laboratories  Computing  Science  Technical
       Report No. 54.

       “A Typesetter‐independent TROFF” by Brian W. Kernighan, 1982, AT&T Bell
       Laboratories Computing Science Technical Report No. 97.

       You  can  obtain  many  relevant  Bell  Labs  papers  in PDF from Bernd
       Warken’s  “roff  classical”  GitHub   repository   ⟨https://github.com/
       bwarken/roff_classical.git⟩.

   [1mManual pages[0m
       As  a system of multiple components, a [4mroff[24m system potentially has many
       man pages, each describing an aspect of it.  Unfortunately, there is no
       consistent naming scheme for these pages among the different  [4mroff[24m  im‐
       plementations.

       For  GNU  [4mroff[24m, the [4mgroff[24m(1) man page enumerates all man pages distrib‐
       uted with the system, and individual pages frequently refer to external
       resources as well as manuals distributed with [4mgroff[24m  on  a  variety  of
       topics.

       With  other  [4mroff[24ms,  you  are on your own, but [4mtroff[24m(1) might be a good
       starting point.

groff 1.23.0                      5 July 2023                          [4mroff[24m(7)
