TrueCombat: Elite (TC:E or TC:Elite) is a total-conversion modification by Team Terminator and Groove Six Studios for the freeware first person shooter game Wolfenstein: Enemy Territory, started in the late 2004. The modification is in the tactical realism genre and supports Windows, Linux and Mac operating systems. It is an offspring to a Quake 3 modification called TrueCombat, which holds some similarity in the game mechanics.

Make sure that the driver to your 3D graphic card is proper installed and working.
Make sure you have a working install of Enemy Territory.

Code:

cd ~/Desktop
wget -c http://dragons-perch.net/tce/true.combat.elite_0.49-english.run
sudo sh true.combat.elite_0.49-english.run

You should be able to launch TCE from your applications list (either in Games or Other).

Enjoy!