Perl Hacks

Hack #15. Alert Your Mac

Schedule GUI alerts from the command line.

Growl (http://www.growl.info/) is a small utility for Mac OS X that allows any application to send notifications to the user. The notifications pop up as a small box in a corner of the screen, overlayed on the current active window (as shown in Figure 2-1).

Figure 2-1. A simple Growl notification

The Hack

You can send Growl notifications from Perl, thanks to Chris Nandor's Mac::Growl. The first thing you have to do is tell Growl that your script wants to send notifications. The following code registers a script named growlalert and tells Growl that it sends alert notifications:

use Mac::Growl;

Mac::Growl::RegisterNotifications(
    'growlalert', # application name
    [ 'alert' ],  # notifications this app sends
    [ 'alert' ],  # enable these notifications
);

Growl displays a notification to let you know the script has registered successfully (Figure 2-2). You need only register an application once on each machine that uses it.

Figure 2-2. A newly registered application

When you want to send a notification, call PostNotification( ), passing the name of the script, the kind of notification to send, a title, and a description:

Mac::Growl::PostNotification( 'growlalert', # application name 'alert', # type of notification "This is a title", ...