Introduction to Linux

Here are a few online resources which are useful for understanding what Linux, Unix and Open Source Software really are.

• History of Unix, Linux, and Open Source / Free Software. It is easy to think that Linux is the same thing as Unix but it’s not.
• What is a Linux distribution?. Linux is a kernel. To be useful, it needs to be bundled with hundreds of system and user applications. The bundle is then called a distribution and myriads exist e.g. RedHat, CentOS, Debian and Ubuntu. Why?
• Open Source Definition by the Open Source Initiative. It is equally easy to think that Open Source Software should always be free (for example). But things are much subtler than that. For example, Red Hat Linux needs to be bought but is still open source…
• Finally, The Cathedral and the Bazaar by Eric Raymond. How can software which is developed by hundreds of developers distributed over the whole planet and who are doing it for free can possibly create Linux, an operating system which is arguably better than most commercial operating systems?

Using Linux

Linux is a powerful operating system which provides both text and graphical interfaces. A system administrator must be comfortable with both environments.

The Linux command line

Linux system administrators need to master the Linux command line as this is, arguably, the most efficient and powerful way to interact with the operating system.

In order to know how to use the command line correctly, we will learn a number of important aspects:

• Shells and the Bash shell in particular
• Commands and sequences of commands
• Environment variables
• Managing the command history
• The system path
• Manual and info pages

The Linux Graphical interface

Typical Linux distributions use either Gnome or KDE as graphical interface. A competent Linux system administrator needs to be comfortable with both.