The GNU Project is a community akin to FreeBSD and other open source projects. It was founded by Richard Stallman as part of the Free Software Foundation and exists to create an operating system similar in operation to UNIX while not containing any UNIX code. This is where the project's recursive acronym originates: 'GNU's Not Unix'.
While the project's original aim for an independent kernel is a long way from completion the operating system tools, such as commands, shells, etc. have been developed and in existence for well over a decade. In fact the tools have been used on the Linux kernel to provide functionality and has been the cause for calling it 'GNU/Linux'.
While FreeBSD and its related family of OpenBSD, NetBSD and others use the BSD Licence to release software the GNU Project uses their own GNU General Public License. There are many differences between the two and often the cause of great debates (or flame wars, depending on the point of view)!
Despite the licensing differences, plenty of GPL licensed code is readily available through the ports and packages systems. This greatly increases the number of applications available to FreeBSD. Some examples of GPL apps available through ports and packages:
- CLAM AV anti virus;
- GCC source code compiler;
- GIMP graphics manipulation;
- MPlayer multimedia playback;
- MySQL database server (RDBMS);
- NMAP network monitor;
- Pidgin instant messenger (an 'emulator' for MSN, ICQ, et al.);
- WINE Windows API emulation (albeit the 'Lesser GPL' license);
- Xine DVD playback;