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

Description:
   This hook is triggered whenever the client observes a nickname change.
   It only hooks once per nick change, not once per channel.

Parameters:
   $0    old nickname
   $1    new nickname

Examples:
   To distinguish the client from another user:
      on ^nickname "*" {
         if ( [$0] == N ) {
            echo *** Your nickname is now $1
         } {
            echo *** $0 has changed nicks to $1
         }
      }

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