GNU general public license is an open source software license which gives complete details on how a software and its accompanying source code can be used in several ways. It specifies on how the end users can copy, modify, run and distribute the software. It is also more popularly referred as GNU GPL. Any individual or company or organization can avail the facility. One important consideration is that the customer that uses the software must also supply it to the other users requiring it under the same license agreement. The license is only meant for copying, modifying and distributing the source code.
The GNU general public license follows the concept of “copyleft”. It is opposite to the customary term “copyrights” which means the rights to that particular material are reserved for a particular entity and is a private exclusive software. Copyleft means it is openly available to the public not cost wise but in the sense the freedom to use. It allows the users to distribute copies of the free software even at a price but on the condition they have to pass on all the freedom to the new users that they have been enjoying. The free software does not carry any warranty. Any modifications made to the software are clearly marked as changed so that in case any problem arises in the modified versions are not connected to the previous writers.
GNU general public license also permits the writers to amend the software and also not release it in public. They can keep it for their personal use, be it an individual or an organization but if they make it available for the others to use they have to adhere to the policies of the GPL and pass on the same rights and benefits that they have been experiencing. GNU in simple terms gives the users freedom to amend a version of the programs and ensures its availability to everyone.