Want to prevent Ubuntu from going to sleep or turning black? Caffeine is a status bar application able to temporarily prevent the activation of both the screensaver and the “sleep” powersaving mode. With that you can enjoy movies without a break.
With caffeine, you can manually disable screensaver by one click:
Or, set automatic activation for flash video, quake live, or other certain programs are running in its preferences window.
To install the applet:
Caffeine is available in the ppa repository for Ubuntu 13.04 Raring, 12.10 Quantal, 12.04 Precise, 10.04 Lucid, and Linux Mint.
Hit Ctrl+Alt+T to open terminal, run command to add the ppa repository:
sudo add-apt-repository ppa:caffeine-developers/ppa
sudo apt-get update
Install the applet:
sudo apt-get install caffeine
Once installed, start it from the Unity Dash.