Growl Arduino Receiver


I'm working on project which I have and Arduino with a Lan Shield and LCD display which displays MQTT messages from a server and an other Arduino which is connected to my doorbell. I want to expand on this by having my growl notifications from my mac display on the LCD as well.

I know that growl can run shell scripts, but i can't figure out how to get it to forward the notifications to the Arduino, have any of you got any idea how i can do this or if there is a libraries that i can use?