The operating system created in 1992 by combining the GNU system, the Linux kernel and other software. Although "Linux" is the name most widely heard, many prefer to use "GNU/Linux" to give credit to the GNU Project, which contributed essential components to the system. The Linux kernel provides the nucleus of the system, but a "Linux distribution" includes a huge amount of software from the GNU Project and other sources (see Linux distribution).

The basic GNU/Linux operating system is open source software because it complies with the "free software" philosophy of the Free Software Foundation. However, most distributions of GNU/Linux include some programs that are neither free nor open source. See GNU Project, Linux, free software and open source.