Debian GNU/Linux, is a Linux distribution composed of free and open-source software, developed by the community-supported Debian Project.

Debian is a free operating system (OS) for your computer.
It provides more than a pure OS: it comes with over 60,000 packages, precompiled software bundled up in a nice format for your machine.
The first version of Debian (0.01) was released on September 15, 1993, and its first stable version (1.1) was released on June 17, 1996.
To give you an idea of how far back that was, Apple was still a sinking company with no real technology in the mainstream market, the first Palm Pilot was released, which revolutionized the mobile devices industry, and the internet did not even exist in many countries.

When most people think about free software, the first thought that usually comes to mind is price. Although it is true that most free software is, in fact, free in price (gratis), that is not the most important part of the essence of free software.

Debian is, without a doubt, The Universal Operating System

Debian is one of the most popular Linux distributions, and many other distributions have been created from the Debian codebase.
As of 2018, DistroWatch lists 141 active Debian derivatives.
The cost of developing all of the packages included in Debian 5.0 Lenny (323 million lines of code) has been estimated to be about US$8 billion.

Debian is freely redistributable.

The license of a Debian component may not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license may not require a royalty or other fee for such sale.

A program is free software if the user has the following freedoms:

  • (Freedom 0) The freedom to run the program as you wish, for any purpose.
  • (Freedom 1) The freedom to study how the program works, and change it so it does your computing as you wish.
  • (Freedom 2) The freedom to redistribute copies so you can help your neighbour.
  • (Freedom 3)The freedom to distribute copies of your modified versions to others.

If these four freedoms are not given to the user, then the program is considered non-free (proprietary).

Debian is and will remain 100% free Linux distribution.

It provides the guidelines to determine if a work is free in the document entitled The Debian Free Software Guidelines.There is a promise that the Debian system and all its components will be free according to these guidelines. Its developers will never make the system require the use of a non-free component, and they support people who create or use both free and non-free works on Debian.