What is Linux?
Linux is a free operating system that works with almost all CPUs, motherboards and computers. There are many different versions, some of which are proprietary, such as Red Hat Enterprise Linux, but most of the versions are free and open source, which means you can download them and install them yourself for free and even use them for your own business without paying anyone (unless you need a consultant to help you install and set it up). Open source means that it is supported largely by volunteers who like computers and programming. Anyone can suggest an improvement or change to the basic Linux operating system, but the change must usually get the approval of a core number of enthusiasts who act sort of like the "board of directors" of that particular version of Linux. The great thing about all the Linux versions or "distros" (distributions) is that there are thousands of programs and games that work with them; many of these software packages are very similar to name-brand programs.
Although the Linux operating system is free, there is a much steeper learning curve to getting it installed and functioning correctly. If you like a challenge and know a little bit about how computers work from the Windows or the Mac operating system, then it shouldn't be too difficult to learn Linux. There are many helpful forums, user groups, and websites that can assist you with any problems or questions.
Linux is based on the old UNIX operating system, which is still around. (UNIX was the basis for the NeXT computer, which Steve Jobs developed in the '90s.) Linux was created by Linus Torvalds, a famous Finnish-American computer programmer, in the '90s, but is still being updated and improved today by Torvalds and thousands of other enthusiasts.
It is very easy to mess up your Linux installation and then have to reinstall it, especially if you are a beginner, so be sure to back up your data frequently. Or don't use it for anything important until you have some facility with it and have a stable Linux system. It can be very satisfying when you figure out a problem or learn a new trick or tip in Linux.
Here are the most popular distros:
Red Hat Enterprise Linux
Linux is generally more secure than the other operating systems, but nothing is perfect, of course, so you still have to take precautions. Some Windows and Mac OS viruses that your Linux system encounters will not infect your computer, but can accidentally be transferred to Windows and Mac machines by e-mail or other transfer methods. There are free or low cost antivirus/antispyware programs that you can download and install that will protect your Linux installation and the Windows/Mac machines of your contacts.