GNU/Linux is a free operating system originally developed by Linus Torvalds in 1993. It’s available for everyone to download, use, modify, and distribute it at no cost. Linux comes in many flavors, commonly known as distributions, such as Ubuntu, Linux Mint, and Fedora.
Free software is one answer to a world built-in proprietary (expensive) code. What does free software mean? Free software is like cooking for yourself. It is more work, but it is cheaper, tastier, you know what you are doing (you have the recipe), and it is better for you. Free software means you are free to download it, use it, copy it, modify it, and redistribute it.
Others: If you want to use the Internet anonymously and circumvent censorship, you may want to use Tails, the distro for the privacy conscious. Steam OS and Ubuntu GamePack are the most popular gaming distros today. Kali Linux is the most widely known Linux distro for ethical hacking and penetration testing. It is a Linux distribution specifically geared towards professional penetration testers and security specialists. Elementary is for those who like a beautiful and elegant looking desktop. It looks a lot like Mac OS.