The Linux operating system (or Linux OS) is an open source, freely available OS that can be installed on a wide range of devices such as desktops, servers, smartphones and tablets, supercomputers, video game consoles, and purpose-built devices from in-car entertainment systems, to the Mars Rover, to medical wearables.
In contrast with proprietary operating systems like Windows and Mac which require licensing fees, Linux is an example of free, open-source software collaboration. The term “open source” refers to the fact that the underlying source code may be downloaded, used, modified and distributed—commercially or non-commercially—by anyone under the terms of its respective licenses, such as the GNU General Public License.
Linux for the desktop comes in a number of different versions, or distributions (distros). Some popular distros are Ubuntu, Linux Mint, openSUSE, Fedora, and Debian. Each distro has its own unique approach to the desktop. A distribution will include the Linux kernel, all of the utilities and libraries needed to make the OS function properly, and a large number of applications that work together to provide the functionality offered by the distro. Linux servers are also available – some are free, and some offer a version that is hardened and refined for the rigors of enterprise use. SUSE Linux Enterprise Server and Red Hat Enterprise Linux are examples of commercial distributions that have been hardened to meet the demands of enterprise customers.
Linux was originally developed for personal computers, but has now been ported to more platforms than any other OS. Linux is a dominant player in the smartphone arena due to the Linux kernel-based Android OS, and is a leading server OS and is the only OS used on TOP500 supercomputers.