Linux ( /ˈlɪnəks/ lin-əks, also pronounced /ˈlɪnʊks/ lin-uuks) is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds. Linux system distributions may vary in many details of system operation, configuration, and software package selections.
Linux runs on a wide variety of computer hardware, including mobile phones, tablet computers, network routers, televisions, video game consoles, desktop computers, mainframes and supercomputers. Linux is a leading server operating system, and runs the 10 fastest supercomputers in the world. In addition, more than 90% of today's supercomputers run some variant of Linux.
The development of Linux is one of the most prominent examples of free and open source software collaboration: the underlying source code may be used, modified, and distributed—commercially or non-commercially—by anyone under licenses such as the GNU General Public License. Typically Linux is packaged in a format known as a Linux distribution for desktop and server use. Some popular mainstream Linux distributions include Debian (and its derivatives such as Ubuntu), Fedora and openSUSE. Linux distributions include the Linux kernel, supporting utilities and libraries and usually a large amount of application software to fulfill the distribution's intended use.
A distribution oriented toward desktop use may include the X Window System, the GNOME and KDE Plasma desktop environments. Other distributions may include a less resource intensive desktop such as LXDE or Xfce for use on older or less-powerful computers. A distribution intended to run as a server may omit any graphical environment from the standard install and instead include other software such as the Apache HTTP Server and a SSH server like OpenSSH. Because Linux is freely redistributable, it is possible for anyone to create a distribution for any intended use. Commonly used applications with desktop Linux systems include the Mozilla Firefox web browser, the OpenOffice.org or LibreOffice office application suites, and the GIMP image editor.
The main supporting user space system tools and libraries from the GNU Project (announced in 1983 by Richard Stallman) are the basis for the Free Software Foundation's preferred name GNU/Linux.