This is an example Ubuntu notifier that can be used with spook (a guard replacement - eg. watch for changes and run something). Clone this gist to:
~/.spook/notifiers/ubuntu
like so:
cd ~
git clone https://gist.github.com/fc803fe80124a0fe1953.git ~/.spook/notifiers/ubuntu
Also make sure you install "notify-send" through apt or this won't work.
and you're good to go.