Linux is an open-source, Unix-like operating system that was developed in 1991 by Linus Torvalds. It began as an alternative to expensive proprietary Unix operating systems that aimed to provide a free kernel for an operating system. The GNU project established in 1984 by Richard Stallman contributed many free software tools to develop a complete free operating system. Major Linux distributions include Red Hat, Debian, Ubuntu, and Linux Mint that bundle the Linux kernel with other free software applications and have gained widespread adoption for servers, desktops, and embedded systems.