usage: AWAY [<flags>] [<away message>]

  Marks you as "away".  Whenever someone sends you a msg or a
  does a whois on you, they automatically see whatever message
  you set.  While you are away, all messages you receive will be
  timestamped and you will optionally get beeped (see help on
  set BEEP_WHEN_AWAY) for each message.  Using /away with no
  parameters marks you as no longer being away.  Some IRC activity is logged
  while your are away.  You will be asked if you want to read and or delete
  the saved messages when you unmark yourself away.

flags:
  -one  Send away message to only the server in the current window.
  -all  (default) send away message to all servers you may be on.

see also help on:
    set BEEP_WHEN_AWAY
    set SHOW_AWAY_ONCE
