I use a system wide notification manager called Growl to handle notifications of all sorts of apps on my Mac, including a number of custom scripts and tools. It’s a really neat little system, and even supports handling notification requests across a network. I was working from a cafe today and fired up a little app called Flame to see what was going on in the network around me. It just shows you all Mac machines connected to the same network and tells you what services they are running.

I spotted someone who had the Growl network service active (_growl._tcp.), so I thought I’d give something a try. According to Flame, their computer was called “Brad’s Computer”, and his IP was 192.168.1.148 so I fired up Terminal and entered the following:

$ growlnotify -H 192.168.1.148 -t "Hi Brad" -m "You should really put a password on Growl network notifications"

Obviously it got through and displayed, because some dude freaked out and his eyes went wide while he stared at his screen. I tried not to laugh.

Surprise! 🙂