What is Linux

The following post is a section of the book 'Just Enough Linux'.  The entire book can be downloaded in pdf format for free from Leanpub or you can read it online here.
Since this post is a snapshot in time. I recommend that you download a copy of the book which is updated frequently to improve and expand the content.

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In it’s simplest form, the answer to the question “What is Linux?” is that it’s a computer operating system. As such it is the software that forms a base that allows applications that run on that operating system to run.

In the strictest way of speaking, the term ‘Linux’ refers to the Linux kernel. That is to say the central core of the operating system, but the term is often used to describe the set of programs, tools, and services that are bundled together with the Linux kernel to provide a fully functional operating system.

An operating system is software that manages computer hardware and software resources for computer applications. For example Microsoft Windows could be the operating system that will allow the browser application Firefox to run on our desktop computer.

Linux is a computer operating system that is can be distributed as free and open-source software. The defining component of Linux is the Linux kernel, an operating system kernel first released on 5 October 1991 by Linus Torvalds.

Linux was originally developed as a free operating system for Intel x86-based personal computers. It has since been made available to a huge range of computer hardware platforms and is a leading operating system on servers, mainframe computers and supercomputers. Linux also runs on embedded systems, which are devices whose operating system is typically built into the firmware and is highly tailored to the system; this includes mobile phones, tablet computers, network routers, facility automation controls, televisions and video game consoles. Android, the most widely used operating system for tablets and smart-phones, is built on top of the Linux kernel.

The Linux mascot ‘Tux’

The development of Linux is one of the most prominent examples of free and open-source software collaboration. Typically, Linux is packaged in a form known as a Linux distribution, for both desktop and server use. Popular mainstream Linux distributions include Debian, Ubuntu and the commercial Red Hat Enterprise Linux. Linux distributions include the Linux kernel, supporting utilities and libraries and usually a large amount of application software to carry out the distribution’s intended use.

A distribution intended to run as a server may omit all graphical desktop environments from the standard install, and instead include other software to set up and operate a solution stack such as LAMP (Linux, Apache, MySQL and PHP). Because Linux is freely re-distributable, anyone may create a distribution for any intended use.

Linux is not an operating system that people will typically use on their desktop computers at home and as such, regular computer users can find the barrier to entry for using Linux high. This is made easier through the use of Graphical User Interfaces that are included with many Linux distributions, but these graphical overlays are something of a shim to the underlying workings of the computer. There is a greater degree of control and flexibility to be gained by working with Linux at what is called the ‘Command Line’ (or CLI), and the booming field of educational computer elements such as the Raspberry Pi have provided access to a new world of learning opportunities at this more fundamental level.

The post above (and heaps of other stuff) is in the book 'Just Enough Linux' that can be downloaded for free (or donate if you really want to :-)).