GNU General Public License

The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses. The GPL is a copyleft license, which means that it guarantees end users the freedom to run, study, share, or modify the software, but if you distribute a derivative work or modification, you must provide the source code to those recipients under the same or equivalent license terms — there is no requirement to publish anything to the public at large. The GPL was the first copyleft license available for general use. It was originally written by Richard Stallman, the founder of the Free Software Foundation (FSF), for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. The GPL states more obligations on redistribution than the GNU Lesser General Public License and differs significantly from widely used permissive software licenses such as BSD, MIT, and Apache. Historically, the GPL license family has been one of the most popular software licenses in the free and open-source software (FOSS) domain. Prominent free software programs licensed under the GPL include the Linux operating system kernel and the GNU Compiler Collection (GCC). David A. Wheeler argues that the copyleft provided by the GPL was crucial to the success of Linux-based systems, giving the contributing programmers some assurance that their work would benefit the world and remain free, rather than being potentially exploited by software companies who would not be required to contribute to the community. In 2007, the third version of the license (GPLv3) was released to address perceived shortcomings in the second version (GPLv2) that had become apparent through long-term use. To keep the license current, the GPL includes an optional "any later version" clause, which allows users to choose between two options –the...