I have a application running on Ubuntu 12.04.2 LTS and I am running an application server like mailman server or faye server on ubuntu screen. The problem is, at times the process that is running on screen gets stopped and my application crashes because of that. Now I want to be notified whenever that 'faye server' or 'mailman server' is stopped that is running on screen. I am using Digital Ocean and I have already setup postfix server.