Linux, in case you’ve never heard, is an open source operating system (OS), and is sometimes a free alternative to running Microsoft Windows on your PC or server. Because of the nature of it’s license, many companies or individuals have the right to compile their own “flavor” and redistribute it, typically with a “brand” name referred to as a distribution.
Two of the more popular enterprise-level distributions are Red Hat Enterprise Linux (RHEL) and Suse Linux from Novell. Because of Red Hat’s license, a distribution called CentOS was created that is basically the same as the Red Hat distribution. Ubuntu is a relatively new distro that is built on the meaning behind the word (see Ubuntu (ideology) on Wikipedia.org)
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