Linux Pocket Guide, 2nd Edition

Name

groupadd — stdin  stdout  - file  -- opt  --help  --version

Synopsis

groupadd [options] group

The groupadd command creates a group. In most cases, you should use the -f option to prevent duplicate groups from being created:

# groupadd -f friends

Useful options

-g gid	Specify your own numeric group ID instead of letting groupadd choose one.
-f	If the specified group exists already, complain and exit.