Synopsis:   This week we pull back the curtain and take a look at some of the parts of Linux underneath the GUI that most people never see. Links: 10 Immutable Laws of Security Linux File Permissions Explained Linux Run Levels Telinit Tips: Command Line: Screens End-user Tip: Linux Certifications- CompTIA and LPI Noob Discovery: Tux the Penguin Tips: Command line of the week: Aptitude