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

Description:
   This hook is triggered whenever the client receives a CTCP message,
   whether directly or one sent to a channel it is on.

Parameters:
   $0    nickname of CTCP message sender
   $1    target of CTCP (client's nickname or channel name)
   $2    type of CTCP
   $3-   arguments to CTCP command, if any

Examples:
   To customize the normal CTCP message:
      on ^ctcp "*" {
         if ( [$1] == C ) {
            echo *** $0 sent a CTCP $2 to $1${[$3] ? [\: $3-] : []}
         } {
            echo *** $0 sent you a CTCP $2${[$3] ? [\: $3-] : []}
         }
      }

See Also:
   ctcp(1); on(5) ctcp_reply

Restrictions:
   Automatic replies from within this hook are limited by the irc protocol.
   Since a CTCP is really just a PRIVMSG, the client may only automatically
   reply with NOTICEs, not MSGs.  Any attempt to send a MSG or CTCP from
   within this hook will result in it automatically being converted to a
   NOTICE (or CTCP REPLY).  This is because the protocol
   specifically forbids such behavior.

Other Notes:
   The client's default behavior of automatically responding to certain CTCP
   messages cannot be suppressed with this hook.  To prevent the client from
   replying to CTCPs, use IGNORE.

