When booting your Linux system, you are usually directed to a graphical user interface that guides you through the login process and the following interactions with the system. Although graphical user interfaces have become very important and user-friendly, using them is not the only way to communicate with your system. You can also use a text-oriented communication like a command line interpreter, usually called the shell, where you can enter commands. Because Linux provides options to start shell windows from the graphical user interface, you can easily use both methods.
In administration, shell-based applications are especially
important for controlling computers over slow network links or if you
want to perform tasks as root on the command line. For Linux
newbies it might be rather unusual to enter commands
in a shell, but you will soon realize that the shell is not only for
administrators—in fact, using the shell is often
the quickest and easiest way to perform some daily tasks.
There are several shells for UNIX or Linux. The default shell in SUSE® Linux Enterprise is Bash (GNU Bourne-Again Shell).
This chapter deals with a couple of basics you need to know for using the shell. This includes the following topics: how to enter commands, the directory structure of Linux, how to work with files and directories and how to use some basic functions, the user and permission concept of Linux, an overview of important shell commands, and a short introduction to the vi editor, which is a default editor always available in Unix and Linux systems.