System administration command. Create new group account group. Options -f and -r are added by RedHat and may not be available on all distributions.
Exit with error if group being added already exists. If a gid requested with -g already exists and the -o option has not been specified, assign a different gid as if -g had not been specified.
Assign numerical group ID. (By default, the first available number above 500 is used.) The value must be unique unless the -o option is used.
Accept a nonunique gid with the -g option.
Add a system account. Assign the first available number lower than 499.