Linux is an open-source operating system that runs on various hardware platforms. It was created in 1991 by Linus Torvalds and is developed collaboratively by its community of users and developers. Linux exists in many different distributions, or "distros", that package the Linux kernel along with other software. Popular distros include Ubuntu, Fedora, openSUSE, Debian, and Arch Linux. Linux is widely used for servers, mainframes, embedded systems, and as an alternative to Windows on desktop computers and laptops. It offers advantages like open source access, customizability, security, and reliability.