#compdef chown chgrp
if [[ CURRENT -eq 2 || CURRENT -eq 3 && $words[CURRENT-1] = -* ]]; then
if [[ $words[1] = chgrp ]] || compset -P '*[:.]'; then
_groups
else
if [[ $OSTYPE = (solaris*|hpux*) ]]; then
_users -S ':' -q
else
_users -S '.' -q
fi
fi
else
_files
fi