Execute a shell script when growl notification is shown

Question

How do you execute a shell script whenever a Growl notification is shown? And make it application specific. For instance, run a the shell script say "You have new mail" whenever a growlMail notification is shown?

Answer 1

To play a custom sound in response to a Growl notification:

• Create a sound file and make it available to the system:

  say -o YouHaveMail "You have Mail"

  creates the sound file, "YouHaveMail.aiff". Sudo cp the file to /System/Library/Sounds/.

• Configure Growl to use that sound for the particular app and notification:

  Growl preference pane | Applications
  In the Application list, select your application.

  Configure | Notifications
  In the Notifications: dropdown, select a notification.
  In the Play Sound: dropdown, select YouHaveMail.

Answer 2

I know you can forward growl notifications to other computers. Perhaps you could forward them to a port on localhost. If you had something listening to that port it could do something every time the notification was forwarded on that port. maybe..?