The GNU Project was launched in 1984 to develop a complete Unix-like operating system which is free software: the GNU system.
GNU’s kernel wasn’t finished, so GNU is used with the kernel Linux. The combination of GNU and Linux is the GNU/Linux operating system, now used by millions. (Sometimes this combination is incorrectly called Linux.)
There are many variants or “distributions” of GNU/Linux. We recommend the GNU/Linux distributions that are 100% free software; in other words, entirely freedom-respecting.
The name “GNU” is a recursive acronym for “GNU’s Not Unix”; it is pronounced g-noo, as one syllable with no vowel sound between the g and the n.
The above text is quoted from the GNU official site.
So , what is GNU?
GNU is a free Unix-like operating system. They started making the operating system in January 1984. You can read the initial announcement at http://www.gnu.org/gnu/initial-announcement.html.
The Free Software Foundation was founded in October 1985, initially to raise funds to help develop GNU.
By 1990 they managed to finish most of the parts of the operating system except for the kernel. In that time a Unix-like kernel, was developed by Linus Torvalds in 1991 and made free software in 1992. Combining Linux with the almost-complete GNU system resulted in a complete operating system: the GNU/Linux system.
Estimates are that tens of millions of people now use GNU/Linux systems, typically via distributions such as Slackware, Debian, Red Hat, and others.
The GNU General Public License (GPL), the GNU Lesser General Public License (LGPL), and the GNU Free Documentation License (GFDL) were written for GNU, but are also used by many unrelated projects.
To learn more about the GNU and the complete history of development, visit the GNU official site at http://www.gnu.org and you can visit the free software foundation site at http://www.fsf.org/
You can even buy a GNU shirt or adopt a Gnu.
http://shop.fsf.org/