groups(1) -- Linux man page

 

NAME

groups - print the groups a user is in  

SYNOPSIS

groups [OPTION]... [USERNAME]...  

DESCRIPTION

--help
display this help and exit
--version
output version information and exit

Same as id -Gn. If no USERNAME, use current process.  

REPORTING BUGS

Report bugs to <bug-coreutils@gnu.org>.  

SEE ALSO

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 coreutils groups

should give you access to the complete manual.