The free OS runs on your phone, your netbook, your desktop, and even your alarm clock. You named your dog Linus and you have Tux wallpaper. Andrew Morton signed your underwear. But how much do you really know about the most pervasive open source project on the planet? Core files, httpd service checks, determining the architecture of a Linux box from the shell — take the Linux IQ Test: Round 2 and find out.