complete -c unexpand -s a -l all        -d 'convert all blanks, instead of just initial blanks'
complete -c unexpand -l first-only      -d 'convert only leading sequences of blanks (overrides -a)'
complete -c unexpand -s t -l tabs -x    -d 'have tabs N characters apart instead of 8 (enables -a)'
complete -c unexpand -s t -l tabs -x    -d 'use comma separated LIST of tab positions (enables -a)'
complete -c unexpand -l help     -d 'display this help and exit'
complete -c unexpand -l version  -d 'output version information and exit'