HOWTO: Run Steam without giving it root access

The following HOWTO tells you how to install the Steam for Linux Limited Beta in a separate user account without giving any root privileges to Steam.This gives you double security:1. None of the Steam programs is ever executed as root, not even the install script2. Steam is not even run with privileges of your primary user account. You are told how to generate a second user account which is a sandbox for Steam.The HOWTO was written and tested on Kubuntu 12.10 amd64 on 2012-12-07.Here it is: http://pastebin.com/cjA1nQpk