Linux is a family of free and open operating systems based on the Linux kernel – an operating system kernel created by Linus Torvalds in the early 1990’s.
Since its release in 1991, Linux’s popularity has grown to the point that it’s now used on the majority of computer servers that power the Internet. It is also used in a broad range of consumer products (such as automobiles, TVs, and even house-holds appliances) and hundreds of millions of Android based smartphones.
With over 1,500 developers contributing over 10,000 changes per release, Linux is arguably the most successful example of the open source software development model at work today.
Linux is often packaged as a distribution (i.e. Debian, Fedora, and Ubuntu, and Red hat Enterprise Linux, etc.) which include other software such as the X Window System as well as programs from the GNU Project.