Chapter 1. Basic UNIX System Concepts

Users and Groups
File Basics
Processes
A Short Introduction to the Command Line
cd: Change Directory
Some Environment Variables and the echo Command
cat: Print the Contents of One or More Files to the Screen
less: a Pager
ls: Listing Files
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.