USAGE: groups [-a | -d] [groupname] [name 1] [name 2] ...

The group command allows you to add personal groups that may
be used to alias a group of people, generally for sending mail.

No flag:  Shows the mud's standard groups and your private groups.

    -a :  Adds a group to your groups info, along with a list of
          at least 1 name, all separated by spaces.
    -d :  Deletes a group, or if you give a list of names, deletes
          that list from the specified personal group.
