groups - print the groups a user is in
groups [OPTION]... [USERNAME]...
--help display this help and exit
Same as id -Gn. If no USERNAME, use current process.
Written by David MacKenzie.
Report bugs to <bug-coreutils@gnu.org>.
Copyright (C) 2004 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The full documentation for groups is maintained as a Texinfo manual. If the info and groups programs are properly installed at your site, the command
info groups
should give you access to the complete manual.