Chapter 1. Basic UNIX System Concepts

1. Users and Groups
2. File Basics
3. Processes
4. A Short Introduction to the Command Line
4.1. cd: Change Directory
4.2. Some Environment Variables and the echo Command
4.3. cat: Print the Contents of One or More Files to the Screen
4.4. less: a Pager
4.5. ls: Listing Files
4.6. Useful Keyboard Shortcuts

The name “UNIX®” may be familiar to some of you. You may even use a UNIX® system at work, in which case this chapter may not be very interesting.

For those of you who have never used a UNIX® system, reading this chapter is absolutely necessary. Understanding the concepts which will be introduced here will answer a surprisingly large number of questions commonly asked by beginners in the GNU/Linux world. Similarly some of these concepts will likely answer most of the problems you may encounter in the future.