Linux is an open source operating system based on the UNIX operating system. Linux is freely distributable and works on a wide range of devices such as desktops, laptops, tablets, netbooks and even video game consoles.
Linux is a version of GNU developed by the GNU Project. The GNU operating system, which is upward-compatible with UNIX, is a completely free software system.
Linux has three primary components: the kernel, the system utility and the system library. The kernel, which is the main component, is responsible for all major activities of the operating system. The kernel also hides irrelevant hardware details from application programs and system programs. System utility programs are responsible for specialized, individual-level tasks. System libraries are special functions that the application programs and system utilities use to access the kernel's features.
The Linux operating system has four main layers: the hardware, the kernel, the shell and the utilities. The hardware layer consists of all peripheral devices such as the hard disk drive and RAM. The kernel interacts directly with the hardware. The shell, which is an interface to the kernel, hides the complexity of the kernel's function from users. Utilities provide users with most of the operating system's functionality.