This tag is for programming questions related to software and tools provided by the GNU ("GNU's Not Unix") project.
The GNU Project is a free software, mass collaboration project, announced on September 27, 1983, by Richard Stallman at MIT. It initiated GNU operating system development in 1984. The founding goal of the project was, in the words of its initial announcement, to develop "a sufficient body of free software [...] to get along without any software that is not free."
To make this happen, the GNU Project began working on an operating system called GNU ("GNU" is a recursive acronym that stands for "GNU's Not Unix"). This goal of making a free software operating system was achieved in 1992 when the last gap in the GNU system, a kernel, was filled by the third-party Linux kernel being released as Free Software, under version 2 of the GNU GPL.