Linux is a Unix-like operating system created by Linus Torvalds in 1991 as a free software alternative to other Unix-like operating system. The key component of Linux is the kernel, also called Linux. Linux is typically distributed with user space applications developed from the GNU Project. Because of this the Free Software Foundation, which created the GNU Project, prefers to refer to the operating system resulting from the combined kernel and applications as GNU/Linux.
Developer Linux Torvalds created Linux in 1991 as he was dissatisfied with the license restrictions of the MINIX operating system, which only allowed distribution for educational purposes. He initially developed the Linux kernel on MINIX, and Linux used MINIX applications. Development eventually moved to Linux when the kernel had matured.
Torvalds initially released Linux under a license that restricted commercial distribution, then in 1992 switched to the GNU General Public License (GPL). The GPL is a free software license and does not contain the same restrictions as Torvalds' initial license choice. After switching the license to GPL, developers worked on porting the GNU Project applications to Linux, creating what is now commonly referred to as Linux or GNU/Linux.
Linux has long been a popular platform for free and open source games such as NetHack. Commercial games began appearing in 1994 when Dave Taylor ported the popular first-person shooter Doom to the platform. With the creation of Loki Software in 1998, porting became more common. Former Loki Software developer Ryan C. Gordon continues to be involved in porting games to Linux to this day.
In 2013, the Steam digital distribution platform was officially released for the Ubuntu Linux distribution.