This is an introductory guide for people learning to use a Linux system. It focuses on command-line usage. This is not because everyone will be doing everything at the command line. On the contrary, there are many useful GUI tools and programs in Linux, and some people will be content to stay with these. However, in contrast to GUI programs, which can be learned largely by “click and try”, the command-line requires some deliberate learning, and reading documentation. The benefit of this investment is that you will learn the tools and tricks of the command line which are in many cases faster, more powerful, and more flexible than any GUI program.