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What is open source

Is a set of principles and practices on how to write software, the most important of which is that the source code is openly available. The Open Source Definition, which was created by Bruce Perens and Eric Raymond and is currently maintained by the Open Source Initiative, adds additional meaning to the term: one should not only get the source code but also have the right to use it. If the latter is denied the license is categorized as a shared source license.

Courtesy: wikipedia