!	 $eterna: mode,v 1.9 2021/03/21 04:29:43 mrg Exp $
!
! Copyright (c) 1990-2021  Michael Sandrof, Troy Rollo, Matthew Green,
! and other ircII contributors.
!
! All rights reserved.  See the HELP IRCII COPYRIGHT file for more
! information.
!
Usage: MODE *|<channel> [+|-]<modechars> [<parameters>]
       MODE *|<channel> [+|-]b [<nick>[!<user>[@<host>]]]
       MODE <nick> [+|-]<umodechars>

  Mode command is quite complicated and it allows channel
  operators to change channel mode, or any user to change
  their personal mode. For a channel mode, <modechars> is one of 
  the following:
    i                - channel is invite only.
    k <key>          - Adds join key <key> to the channel.  Keys can
                       added or removed (MODE <channel> -k <key>),
                       but not changed.
    l <number>       - channel is limited, where <number> is the
                       maximum number of users allowed.
    m                - channel is moderated (only channel operators
                       talk).
    n                - No MSGs to the channel are allowed
                       from someone outside the channel.
    o <nick>         - Makes <nick> a channel operator.
    p                - channel is private.
    s                - channel is secret.
                       Note: On 2.8 servers you cannot set both +p
                       and +s modes
    t                - Topic limits, only the channel operators may
                       change it.
    v <nick>         - Gives someone a voice to talk on a moderated
                       channel.
    b user!nick@host - Adds ban.
    e user!nick@host - Adds ban exception.
    I user!nick@host - Adds need-invite exception (notice uppercase I).

  A + or - sign determines whether the specified mode should be
  added or deleted.
  If you supply * as channel name, modes will apply to your current channel.

  The form which takes user!nick@host is special in that
  it needs specifying a sting of the form nick!user@host.
  Banning examples:
    MODE #MyChannel +b *!*@gus.*
  bans everybody from the channel who is on IRC from any
  machine whose name is gus.
    MODE #MyChannel +b netw1z
  bans anybody using the nickname netw1z.
    MODE #MyChannel +b *!merklin@*
  bans anybody whose user name is merklin.
    MODE #MyChannel +b jerk!tug@boat.edu
  bans the user tug@boat.edu from the channel whenever he
  is using the nickname "jerk".

  You can list the bans in effect on a channel:
    MODE #MyChannel b
  With the same way, you can list invite-exceptions on a channel:
    MODE #MyChannel I
  And ban exceptions:
    MODE #MyChannel e
  
  The third form of the MODE command allows you to modify your
  personal parameters. You can precede any combination of the
  following with + or - (+to switch that mode on, - to switch it off).

    o        - IRC operator status. You may not turn this on
               with mode. To assert operator status, you must use OPER
    w        - Receive WALLOPS (messages directed at all operators.
               see WALLOPS.
    s        - Receive server notices. This includes KILL notices
               and notices about what is happening with links
               to the local server.
    i        - Render yourself invisible. This prevents you from
               being seen in WHO and WHOIS information, unless
               somebody specifies your exact nickname with WHOIS.
               This is quite useful, because it often let's you
               "idle in peace" without getting harmed by mass
               advertisers etc.

Note:
  Attempting to avoid a ban placed on you may result in
  forcible removal from IRC or being banned from your server.