cd ${TMPDIR:=/var/tmp}
rm -f u

${THIS_SH} -c 'exec 10>&1; echo fd 10 >&10' 10>u
cat u
rm -f u

${THIS_SH} -c 'exec 8>&1; echo fd 8 >&8' 8>u
cat u
rm -f u

exec 10>u
exec 10>&1; echo 'fd 10' >&10
cat u
rm -f u
exec 10>&-

exec 8>u
exec 8>&1; echo 'fd 8' >&8
cat u
rm -f u
exec 8>&-

rm -f infile
cat > infile <<EOF
1
2
3
4
EOF

exec 7<&0
exec 10<infile
exec 0<&10; cat <&10
exec 0<&7
exec 7<&-

exec 7<&0
exec 8<infile
exec 0<&8 ; cat <&8
exec 0<&7
exec 7<&-

exec 7<&0
exec 0</dev/null
exec 10<infile
exec 10<&0; cat <&10
exec 0<&7
exec 7<&-

exec 7<&0
exec 0</dev/null
exec 8<infile
exec 8<&0; cat <&8
exec 0<&7
exec 7<&-

rm -f infile

cd $OLDPWD
exit 0
