Linux is the name of a free computer operating system and its kernel. It is the most famous example of free software and of open-source development.
"Linux" strictly refers to the Linux kernel, but the name is commonly used to describe the entire Unix-like operating system (also known as GNU/Linux) formed by combining the Linux kernel with the GNU libraries and tools, and for whole Linux distributions, which typically also bundle large quantities of software, such as web servers, programming languages, databases, desktop environments like GNOME and KDE, and office suites like OpenOffice.org.
Definition taken from wikipedia.
The GNU/Linux Operating System has been steadily growing in popularity, and with recent distribution releases has become a very powerful, and user friendly desktop operating system. Linux is an Open Source Operating System, and many users like to keep to purely Free/Open Source Software, which is just as capable as the proprietory equivalents.
Their are many ways of getting started with Linux, from buying fully supported Boxed Distributions to downloading CD/DVD images from the Distribution's website, with Magazine cover disks in between. If you would like to try Linux but are concerned about fully committing your computer to a new OS, you can either Dual-Boot (install Linux alongside Windows/Mac OS and select your desired Operating system on start-up) or try a Live CD. Live CD's are the most pain free way to try Linux, as it runs completely from RAM and doesn't touch the hard drive at all - although a Live CD will always run slower than if it were installed to the Hard Drive.
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