Do you deal with UNIX or Linux?

You are at the right place! Go with me and I will show you some good sites with explanations and explained material for all levels UNIX or Linux users, I have found:
Unix:

• Are you a Beginner? Want to be an Expert? When you should visit A Complete Tutorial for UNIX. It will show you what is UNIX and you will get a step by step tutorial information so it’s good place to start!
• Like lectures and exercises? Visit UNIX\Linux Lectures and Exercises. On this site you will find lecture notes and exercises that were designed to support an intensive introductory course on UNIX or to act as a reference to users who are new to UNIX. Applies both for UNIX and Linux users.

Linux:

• Are you in a hurry? Need Quick Linux Tutorial? You will find a quick Hands-On tutorial to start understanding what is going on, Enjoy!
• What about some Linux Shell Scripting Tutorial? You will find there basic questions and explained answers along with some chapters about shell programming. Give it a chance!.

Maybe you prefer a PDF\DJVU Book, and if you will something interesting just share with us.