Copyleft

ops culture

A licensing mechanism (the GPL family) that permits modification and redistribution on one condition: the redistributed version must carry the same freedoms forward. Copyright law used against its usual grain - the share-alike rule is the mechanism, the pun is the philosophy.

The counterpart family is permissive licensing (MIT, BSD, Apache): keep the notice and otherwise do as you like, including closing the code into proprietary products. Copyleft protects the freedom of the code downstream; permissive maximizes the freedom of the next developer. Both families sit fully inside the free-software and open-source definitions.

Also known as: share-alike

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