ircII help: hook

Usage: HOOK <anything you want>
  This command sends <anything you want> in such a way that it can
  be caught by
    ON HOOK "anything you want"
  or any regular ON syntax. E.g. if you have
    ON HOOK * echo one $* three
  and you send
    HOOK two
  it will display "one two three" as the ON is activated.
  This is useful if you want to put a special hook in a script or 
  alias that you can act upon with an ON HOOK or ignore at will.

See Also:
  ON
  ON HOOK