Linux and Unix are two of the most popular operating systems in the world. An operating system is the basic system software on a computer which determines the basic paradigm of how the system is organized and how it will run. There are many operating systems - dozens of popular ones; however there are three operating systems which have the widest distribution and the highest level of popularity - these are the Microsoft Windows operating system, the Mac OS operating system with products from Apple, and the Linux or Unix operating systems. Unix predates Linux and was the most popular operating system on the internet during the early days of the internet's development - it remains one of the most popular operating systems for business purposes as well as for running servers on the world wide web.

One of the distinguishing features of Unix from early on has been its easy and transparent support for connections between processes on different computers - Unix was designed for systems which were networked at academic and government institutions and is one of the easiest systems to use if you are designing web software or programs which need to communicate consistently over the internet. Unix is also unusual among the operating systems in that it was written in a high level programming language, instead of low level machine language. Because of this, the Unix operating system could be compiled easily on a wide range of systems and was very compatible wherever it was used, which helped lead to its wide usage across the net.

Linux was developed as a free variant of Unix - giving you the internet connectivity and the same general paradigm of systems operations as Unix but with a system which is free for anyone to use. The first version of Linux was released in 1992 using the GNU license for free software. Since then a number of variants of Linux have been developed, such as Red Hat, Mandrake and Debian. Some of these installations of Linux have been released in software stores in commercial boxes for easy installation, although the software itself is generally completely free on the world wide web and you can download it from any of the Linux development sites.

Both people who are computer hobbyists, interested in the theoretical and practical issues of computer science and free software, and people who are putting together computer systems for commercial purposes have used Unix and Linux for their online servers. All of the most popular software packages on the world wide web such as Mysql, PHP and Ruby on Rails are fully compatible with Unix, and are generally compatible with the majority of versions of Linux. Most University computer science courses will expect students to learn the basics of Unix so that they can get around the academic systems and program things which will work over the communications lines of the world wide web. You can learn how to use Unix and Linux from lots of sites on the internet and the basic commands for getting around the system and for scripting are easy to learn.