Synopsis:
   on [<modes>]msg [<serial#>] [-|^]<match> { <action> }

Description:
   This hook is triggered whenever the client receives a MSG from another
   client.

Parameters:
   $0    nickname of message sender
   $1-   text of message

See Also:
   msg(1); on(5) encrypted_privmsg, notice, send_msg

Restrictions:
   The client does not permit automated responses to a MSG with another MSG.
   Such replies may use NOTICE instead.  Any attempt to use MSG within this
   hook will be automatically converted to a NOTICE.  The whole point of
   this is to prevent loops between clients.