Command Line Interface

Finding your way around in Unix or Linux

Please practice your command line skills on a test system, not on a production system. Talk to the administrator if you need access to a test system to practice.

In this document, there are several key terms. These will be italicized. You may need to look up these terms to get a full understanding of them. Commands are generally shown in bold.

In these notes, I will assume your Linux home directory is

/home/username

If you have a different path, adapt!

Generally, these notes show commands in;

bold letters or in a separate

code block for showing commands

Be careful, it can be hard to see where the spaces are. If you get an error when you type a command, the chances are you have missed a space somewhere. Linux also uses the “.” symbol in places, for this reason, I leave out full stops on any line which ends with a Linux command.

In Linux, the characters are also CaSe SeNsItIvE! If you create a file called Computing.txt, this is a completely different file from one called computing.txt

There are times when we need to press and hold a control key, or an alt key, and then press a letter. For example, in these notes if I want you to press and hold the ctrl key and then press the letter d key, I show it as [ctrl][d].

Linux systems have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of Linux (via the terminal and its shell) is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in an SSH or telnet session, or on a server which does not have a GUI at all. Note that it is normal practice to not have a GUI on any production server.