Linux is an Open Source Operating System. An operating system is the set of basic programs and utilities that make your computer run. It was created by Linus Torvalds back in 1991 when he was studying computer science at the University of Helsinki. For understanding Linux better lets first discuss Linux Kernel and its distributions.
In an operating system, "Kernel" is like a middleman sitting between computer hardware and application programs. It receives requests from the application programs and provides access to requested hardware, acting as an interface between them. The required programs, tools and utilities to serve Linux as a fully functional OS totally depends on you. So it is more accurate to consider Linux as a kernel. You are free to configure Linux OS with tools and programs of your choice and requirement.
Programmers and Organizations started designing their own custom operating systems using Linux Kernel. You can also build your own custom operating system by having Linux Kernel as the backbone and selecting tools, utilities, and programs as per your requirement. Doing so is a very complex task and the resulting system may not function as you would have expected.
Many popular operating systems were already developed using Linux Kernel like Ubuntu, Fedora, Debian and the list go on. They have a large community which actively provides support, so instead of creating your own flavor of Linux, you can use an existing one which suits your requirement. We will discuss different distributions in detail in another article. For a beginner the following distributions are good choice:
Linux Kernel is generally bundled with GNU tools and utilities to provide a full set of functionality an operating system should have. GNU is also an open source project and all software created by them are free and released under their own Open Source License like GPL License. For that reason, the operating system created with GNU tools and utilities are often referred to as GNU/Linux. However, not all Linux distributions use GNU components as part of their System. For example, Android relies very little on GNU tools and yet uses Linux kernel at its core.
Linux development is far from over, and developers are working around the clock to make it more reliable and secure with time. If you are a developer and Linux is on your list, install a distribution which suits your requirement and start learning it today.
There are many resources available online for learning linux. I will mention a couple of them here: