Linux is a free and open-source operating system kernel, the core part of an operating system that manages the hardware and runs programs. In everyday speech, "Linux" usually means a complete operating system built around that kernel. Linux runs on most of the world's web servers, on all of the most powerful supercomputers, on Android phones and on countless devices from routers to cars, and it is also a popular choice for desktop computers.

A short history

Linux was started in 1991 by Linus Torvalds, then a student at the University of Helsinki, as a hobby project. He announced it on a Usenet newsgroup and published the source code, and developers around the world soon began to contribute.

The kernel was combined with tools from the GNU Project, which Richard Stallman had started in 1983 with the goal of building a completely free Unix-like system. That combination is why some people prefer the name "GNU/Linux" for the full operating system.

Linux is released under the GNU General Public License version 2 (GPLv2). Anyone can use, study, modify and share it, but changed versions that are distributed must stay under the same license.

How Linux is organised

• Kernel – manages memory, processes, files and hardware drivers.
• System tools and libraries – the basic programs and shared code, many from the GNU Project.
• Shell – the command-line interface, most often Bash.
• Desktop environment (optional) – the graphical interface, such as GNOME, KDE Plasma or Xfce.
• Package manager – installs, updates and removes software from the distribution's repositories.

Distributions

A distribution ("distro") is a complete Linux operating system put together by a company or a community: the kernel, tools, desktop, installer and a curated set of software packages. Some well-known ones:

Distribution	Typical use
Ubuntu	Desktop and server, very popular and beginner-friendly
Debian	Stable base for servers and desktops; many other distros are built on it
Fedora	Up-to-date desktop and developer system, sponsored by Red Hat
Red Hat Enterprise Linux (RHEL)	Commercial enterprise servers with paid support
Linux Mint	Desktop for people coming from other systems
Arch Linux	Minimal, do-it-yourself system for experienced users
openSUSE	Desktop and server, known for its YaST configuration tool

Where Linux is used

• Servers and the cloud – Linux is the dominant operating system for web servers and cloud computing.
• Supercomputers – every machine on the TOP500 list of the world's fastest supercomputers has run Linux since 2017.
• Phones – Android is built on the Linux kernel.
• Embedded devices – routers, TVs, set-top boxes, cars and many industrial devices.
• Desktops and laptops – for developers, administrators and anyone who prefers a free system.
• Containers – technologies like Docker and Kubernetes are built on Linux kernel features.

Why people choose Linux

• Free – no license fees for most distributions.
• Open source – you can see and change how everything works.
• Stable and secure – a long track record on servers, and a permission model that limits damage from mistakes.
• Flexible – runs on old hardware as well as on the newest servers, and can be shaped to almost any purpose.
• Package managers – software is installed and updated from trusted repositories with one command.
• Strong command line – powerful for automation and server administration.

Getting started

1. Pick a beginner-friendly distribution, such as Ubuntu, Fedora or Linux Mint.
2. Try it without installing: most distributions can boot from a USB stick as a "live" system.
3. Install it alongside your current system or on a spare computer.
4. Learn a few basic commands: ls, cd, cp, mv, rm, man, and your distribution's package manager.

Official sources

• The Linux kernel: https://www.kernel.org/
• The Linux Foundation: https://www.linuxfoundation.org/
• The GNU Project: https://www.gnu.org/