GNU

"GNU's Not Unix". The GNU project was started by RichardStallman in 1984 to create a complete free Unix system. By creating various utilities which could be used under other Unix'es as well, they have created a lot of programs which are considered to be the standard toolkit on any Unix machine. Their Operating system (known as Hurd) would be a major step in the project's goal.

GNU's home page is at http://www.gnu.org