The GNU General Public License (GPL) is a widely used free software license that guarantees end users the freedom to use, study, share, and modify software. Created by the Free Software Foundation (FSF), the GPL is a cornerstone of the open-source software movement. Below is a summary of its key principles and terms:
1. Key Principles of the GPL
(a) Freedom to Use
Users can run the software for any purpose without restrictions.
(b) Freedom to Study
The source code of the software must be available, allowing users to study how it works and make changes if desired.
(c) Freedom to Share
Users can redistribute the software to others, either as is or with modifications, under the same license.
(d) Freedom to Modify
Users can modify the software and distribute their modified versions, provided they also comply with the GPL terms.
2. Distribution and Derivatives
When distributing GPL-licensed software or its derivatives:
You must include the original source code or make it available upon request.
The distributed software must also be licensed under the GPL, preserving the same freedoms for future users.
Any modifications must include a clear notice that changes were made.
3. Copyleft Requirement
The GPL ensures that any derivative work remains free and open-source. This "copyleft" principle means that:
If you incorporate GPL-licensed software into your project, the entire project must also be released under the GPL if distributed.
This prevents proprietary use of GPL software.
4. No Warranty
GPL-licensed software is provided "as-is" without any guarantees of functionality or support. Users assume all risks associated with using the software.
5. Compatibility
The GPL is compatible with many other free software licenses, but not all. Developers must ensure that all components of their project comply with the GPL if they use GPL-licensed software.
6. Applicability
The GPL applies only when GPL-licensed software is distributed. If you use the software privately or modify it for personal use without distributing it, you are not required to share the source code or changes.
7. Variants of the GPL
The GPL has several versions, with the most common being:
GPLv2: Introduced in 1991, focusing on user freedoms and copyleft.
GPLv3: Released in 2007, with updated provisions addressing software patents, digital rights management (DRM), and compatibility with other licenses.
8. Examples of GPL Software
Many popular software programs are licensed under the GPL, including:
The Linux kernel.
WordPress (a platform used on OverflowDigital).
GNU utilities and tools.
9. Your Rights as a User
When using GPL-licensed software, you are entitled to:
Access the source code.
Use the software for any purpose.
Share the software freely.
Modify the software and distribute the modified version under the same license.
10. Contact for Questions
For more information on the GNU General Public License, visit the Free Software Foundation website.
Disclaimer: This summary is provided for informational purposes only and does not constitute legal advice. For detailed information, refer to the full GPL text.