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

Description:
   This hook is triggered whenever the client observes someone signoff from
   irc.  It is not hooked when the client itself signs off.

Parameters:
   $0    the channel the signoff was observed on
   $1    the nickname of the person leaving irc
   $2-   signoff message

Examples:
   To distinguish signoffs from one channel to another:
      on ^channel_nick "*" {
         if ( [$0] == C ) {
            echo *** Signoff by $1 \($2-\)
         } {
            echo *** Signoff by $1 from $0 \($2-\)
         }
      }
   
See Also:
   on(5) quit, signoff; quit(1)

Other Notes:
   This hook is not triggered by the client exiting irc.  Use the QUIT hook
   to perform an action when the client quits.  This hook differs from the
   SIGNOFF hook in that this is triggered for every channel on which the
   person is observed signing off.