Linux Tutorial for Advanced Users

This is by far one of the best tutorials on Linux for advanced users from Linux.org

http://www.linux.org/lessons/advanced/book1.html

Some of the examples given in the tutorial are now a bit dated given that the article was written in circa 2006, but the topics are very pertinent for system administrators and web application developers using php, python or perl.

If you are new to linux consider the beginner and the intermediate level tutorial though it may be easier to follow a good book on Linux before starting with this tutorial.