Linux
Linux is a family of Unix-like operating systems based on the Linux kernel, which includes one or another set of utilities and programs of the GNU project, and possibly other components. Like the Linux kernel, systems based on it are typically built and distributed according to the free and open source software development model. Linux-systems are distributed mostly free of charge in the form of various distributions - in a form ready for installation and convenient for maintenance and updates - and having their own set of system and application components, both free and, possibly, proprietary.