Synopsis:
   lusers [<server mask> [<remote server>]]

Description:
   LUSERS (shorthand for list users) returns some summary information
   about who is currently using the network.  It shows how many users
   are currently online (broken up between visible and invisible users),
   the number of channels formed, and the number of servers currently
   connected to the network.  Some servers may return other information
   as well, such as the maximum number of clients that have connected
   to it at one time, or the maximum number of users on the network at
   once (from its perspective).

   If a server mask is specified, the data returned will only apply to
   servers matching that mask.  If a remote server is specified as well,
   that server is queried for the LUSERS information instead of the
   client's current server.

Other Notes:
   Servers using "dog3/super" patched code may disallow use of the LUSERS
   command from time to time.  Such servers have a "high traffic mode",
   in which certain commands are disabled to conserve server resources.
   A 263 numeric will be returned if LUSERS is unavailable.