This session will take you through the basics of Linux, an operating system commonly used to run webservers.
You're advised to read through Part 1 first. After this, you should login to our pre-installed Linux system. Once you have an OS to play with, you should then read through Part 2 and 3, trying out some of the commands (you'll be able to navigate round, just not use the commands demanding superuser access).
For more information on Linux, especially Linux administration, good starter books include Linux All-in-One For Dummies and Linux: The Complete Reference, though almost any similar book covering installation and security will do. Also, there's a good basic Unix tutorial at Surrey University's Electronic Engineering dept.