GNU/Linux – це операційна система: серія застосунків, які дозволяють взаємодіяти з комп’ютером та запускати інші додатки.

Операційна система складається з різноманітних ключових програм, які потрібні комп’ютеру для спілкування з користувачами та отримання від них інструкцій, для читання та запису/передачі даних на жорсткі диски, стрічки та принтери, для контролю використання пам'яті та для запуску іншого програмного забезпечення. Найважливішою складовою операційної системи є ядро. У системі GNU/Linux основним компонентом ядра є Linux. Решта системи складається з інших програм, багато з яких були написані Проєктом GNU або для нього. Оскільки ядро Linux не є самостійною операційною системою, ми вважаємо за краще для позначення систем, які багато людей називають просто «Linux» використовувати термін «GNU/Linux».

GNU/Linux is modelled on the Unix operating system. From the start, GNU/Linux was designed to be a multi-tasking, multi-user system. These facts are enough to make GNU/Linux different from other well-known operating systems. However, GNU/Linux is even more different than you might imagine. In contrast to other operating systems, nobody owns GNU/Linux. Much of its development is done by unpaid volunteers.

Development of what later became GNU/Linux began in 1984, when the Free Software Foundation began development of a free Unix-like operating system called GNU.

The GNU Project has developed a comprehensive set of free software tools for use with Unix™ and Unix-like operating systems such as GNU/Linux. These tools enable users to perform tasks ranging from the mundane (such as copying or removing files from the system) to the arcane (such as writing and compiling programs or doing sophisticated editing in a variety of document formats).

While many groups and individuals have contributed to GNU/Linux, the largest single contributor is still the Free Software Foundation, which created not only most of the tools used in GNU/Linux, but also the philosophy and the community that made GNU/Linux possible.

The Linux kernel first appeared in 1991, when a Finnish computing science student named Linus Torvalds announced an early version of a replacement kernel for Minix to the Usenet newsgroup comp.os.minix. See Linux International's Linux History Page.

Linus Torvalds continues to coordinate the work of several hundred developers with the help of a number of subsystem maintainers. There is an official website for the Linux kernel. Information about the linux-kernel mailing list can be found on the linux-kernel mailing list FAQ.

GNU/Linux users have immense freedom of choice in their software. For example, they can choose from a dozen different command line shells and several graphical desktops. This selection is often bewildering to users of other operating systems, who are not used to thinking of the command line or desktop as something that they can change.

GNU/Linux is also less likely to crash, better able to run more than one program at the same time, and more secure than many operating systems. With these advantages, Linux is the fastest growing operating system in the server market. More recently, Linux has begun to be popular among home and business users as well.