What is Linux?

Linux is an operating system, which is free and open-source. Linux is the name given to all of the UNIX-like operating systems that are based on the Linux kernel. Those different operating systems are called Linux Distributions. 

It is probably the most popular free open-source software there is. 

Linux is a part of the LAMP bundle, where the L stands for Linux OS. The different distributions of Linux are targeted at different user groups. They differ in interface, system tools, and various other features:

• The desktop distributions are used mainly in the home or in the office, by end users. 
• The server distributions are as the name suggests used for servers. Lots of the desktop distributions can and are being used as server distributions as well.
• The most popular distributions of Linux are Debian, Ubuntu, Fedora, Linux Mint, CentOS, openSUSE and many others.