One of the coolest things that Linux has to offer is the concept of virtual terminals. Back in the days of MS-DOS, one program could only be run by one user at a time. Linux in non-graphics mode may resemble MS-DOS somewhat, but that's where the similarities end. Linux is a true multi-tasking, multi-user system. Unlike MS-DOS, you can work as more than one user with more than one program at a time The ALT-F keys Let's say, if you were working as a user, 'bob' for example, and you found that you needed to do something as 'root'. You wouldn't have to shutdown the program you were working with. You could just press ALT-F2 and Linux will prompt you to login as a different user, in this case, 'root'. You'd just type the root password and then you can do stuff as 'root'. Pretty cool, wouldn't you say? The combination of ALT, plus the F keys will allow you to login as a different user, or as the same user, but to run a different program. All you then need to do is type: 'exit' when your finished, and then press ALT-F1 again to get back to your original terminal . A preview of virtual terminals in X-window It's true that the 1990's brought us the era of the graphic user interface, popularized by Macintosh and Microsoft Windows. This gave us the opportunity to have various programs running at the same time. The X-window system of Linux will let you do this as well, but then we can add the concept of multi-user to it. If you've been experimenting with your windows manager already, you might want to try one more thing. The combination CRL-ALT-F6 will get you out of your windows manager momentarily so you can login as a different user. Pressing ALT-F7 will get you back to your windows manager again. We'll mention this again in the lesson on X-window.