Linux is a free Unix-like computer operating system that is actively developed by a number of companies and unaffiliated enthusiasts.
Some of the major contributors are: Red Hat, Google, Microsoft, Dell, IBM, HP, Oracle, Oracle, Novell, and Nokia.

It runs on mobile phones, tablet computers, network routers, televisions, video game consoles and is the leading operating system on servers and other big systems such as mainframe computers and supercomputers, more than 90% of today’s 500 fastest supercomputers run some variant of Linux. (see link)

Linux is the dominant platform now for smartphones, web servers, and super-computers and is a foundational element of the largest and most powerful technology companies and websites today (Google, Amazon, Samsung, IBM, Facebook, Wikipedia, etc).

The main component of Linux, the kernel, is the biggest active software project in history, being the most prominent example of free and open source software collaboration: the underlying source code may be used, modified, and distributed (commercially or non-commercially) by anyone under the GNU General Public License. Because of the fact that any programmer in the world can have a look at the source code (the “recipe” of any program), Linux is pretty close to being free of viruses. More eyes make fewer security flaws that can be exploited by viruses and malware.

Typically Linux is packaged in a format known as a Linux distribution (distro) for desktop and server use. A distro usually comes with a various pre-selected packages installed, and a graphical user environment (several nice looking choices are available: Gnome, KDE, Cinnamon, Unity, Xfce, LXDE, Enlightenment, etc)

Some popular mainstream Linux distributions include Debian (and its derivatives such as Ubuntu and Linux Mint), Fedora (and its derivatives such as Red Hat Enterprise Linux and CentOS), OpenSUSE, and Arch Linux. An interesting time graph with all the known linux distributions since its inception can be seen here.

Linux distributions include the Linux kernel, supporting utilities and libraries and usually a large amount of application software to fulfill the distribution’s intended use.

Installing, updating and removing software in Linux is typically done through the use of simple applications called package managers. These package managers are using  extensive online repositories, containing tens of thousands of packages.

Due to it’s stability and, the use of Linux distributions in home and enterprise desktops has been growing. They have also gained popularity with various local and national governments.

- Since 2009 the White House have moved their computers to a Linux platform based on Red Hat Linux and Apache HTTP Server. (see link)

- Russian military started creating its own Linux distribution, under the name of G.H.ost Project (see link)
- State owned Industrial and Commercial Bank of China (ICBC) has installed Linux in all of its 20,000 retail branches as the basis for its web server and a new terminal platform. (see link)
- The French Parliament has switched to using Ubuntu on desktop PCs (see link), and now is trying to make free software law for higher education (see link)
- CERN (European Organization for Nuclear Research) partnered with Fermilab (Fermi National Accelerator Laboratory) to produce Scientific Linux, a distribution based on Red Hat Enterprise Linux especially for internal use in research
- NASA used Linux in their last Mars mission (see link)
- The London Stock Exchange uses the Linux based MillenniumIT Millennium Exchange software for its trading platform (see link)

Though, the list can be never ending, here is a list that includes the most popular reasons why one should try to use Linux:

  1. Linux gives freedom for software vendors and customers, so everyone has a level playing field, that encourages competition, thus benefiting customers, software vendors, and innovation in general.
  2. Since Linux has a wide range of hardware support and is customizable, it can be trimmed down (or built up) just to run on that particular hardware, that enhances the performance, reduces the footprint and cost of the device.
  3. Linux is free (as in freedom), so it can be used to solve specific problems in your local community e.g reducing language barrier to learn some software. When that software efficiently solves local problem, it can be scaled up to solve similar problems in global scale. This idea is reverse of what traditional software does, someone else trying to guess what local problems you need to solve using software.
  4. Linux can be used to plan and get your business setup very fast. There is almost no lack of software that can help you get your business started. After you get it running, you can invest time on refining the software you use, to help everyone else (or the platform), just as you got help from them. This is the heart of what open source is all about. Do it fast, do it without burden, and return back to improve overall experience.