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

Description:
   This hook is triggered whenever anyone on a channel common to the client
   changes nicknames.  It is triggered for any nickname change, including
   the client's.

Parameters:
   $0    the channel on which the nick change was observed
   $1    the person's old nickname
   $2    the person's new nickname

Examples:
   To make a distinction between the client changing nicks and other people:
      on ^channel_nick "*" {
         if ( [$0] == C ) {
            if ( [$1] == N ) {
               echo *** You have changed nicks to $2
            } {
               echo *** $1 has changed nicks to $2
            }
         } {
            if ( [$1] == N ) {
               echo *** You have changed nicks to $2 on $0
            } {
               echo *** $1 has changed nicks to $2 on $0
            }
         }
      }

See Also:
   nick(1); on(5) nickname

Other Notes:
   This hook differs from the NICKNAME hook in that it is triggered once per
   nick change per channel, whereas NICKNAME is only triggered once per nick
   change.