LIST ACTIVE [wildmat]

    LIST ACTIVE is exactly the same as the LIST command specified in
    RFC977. The responses and the format should exactly match the LIST
    command without arguments.  If the optional matching parameter is
    specified, the list is limited to only the groups that match the
    pattern.  Specifying a single group is usually very efficient for
    the server, and multiple groups may be specified by using wildmat
    patterns (described later in this document), not regular
    expressions. If nothing is matched an empty list is returned,
    not an error. This command first appeared in the UNIX reference
    version.