GNU GPL Explained: Delving into the What and Why of this Essential Definition

The GNU General Public License (GNU GPL or simply GPL) is a widely used free software license, which guarantees end-users the freedom to use, study, share, and modify the software. It has been applied to more than 71% of free and open-source software projects and has played a significant role in the success of the open-source movement. Created by the Free Software Foundation, the GNU GPL ensures that software licensed under its terms remains “free” for users and developers alike.

“Free software is a matter of liberty, not price. To understand the concept, you should think of ‘free’ as in ‘free speech,’ not as in ‘free beer’.” – Richard M. Stallman

What is GNU GPL? Definition of GNU General Public License

The GNU General Public License is a copyleft license that allows users and developers the legal permission to copy, distribute, and/or modify a given software under specific terms and conditions. It was created by Richard Stallman and the Free Software Foundation (FSF) to protect the rights of users and developers of software distributed under the license. The GPL ensures that the software and its source code will always remain free and open to the public, preventing any proprietary or closed-source adaptations of the work.

ℹ️ Synonyms: General Public License, Free Software License, Copyleft License, Open Source License, GPL

How it Works

When a developer releases their software under the GPL, they are giving users a set of permissions and restrictions that govern how the software can be used, distributed, and modified. Some of the key aspects include:

1. The software can be used for any purpose, free of charge.
2. The software source code must be made available with any distribution of the software.
3. Any modified versions of the software must also be released under the GPL.
4. Credit must be given to the original developer and copyright holder.

This ensures that derivative works will also remain open and free, fostering a community of shared knowledge and collaboration.

Benefits of using GNU GPL

• Freedom to use, modify, and distribute the software, promoting collaboration and innovation.
• Ensures that software remains open-source, preventing attempts to make proprietary versions of the code.
• Creates a level playing field by allowing anyone to access and benefit from the software and its source code.
• Encourages transparency and democratic control of technology, as users have the right to study and modify the software to suit their needs.
• Supports the growth of the open-source ecosystem, benefiting both individual software projects and the wider IT industry.

GNU GPL use cases

The GNU GPL has been applied to a wide range of software projects, some of the most notable examples are:

1. Linux kernel: The core component of the Linux operating system, released under the GNU GPL in 1991 by Linus Torvalds. This has been integral to the success and widespread adoption of Linux as a free and open platform.
2. WordPress: A popular content management system (CMS) and website builder used by more than 30% of the internet, released under the GNU GPL in 2003.
3. MySQL: A widely used open-source relational database management system, GPL licensed since 2000.

These high-profile projects demonstrate how the license can promote growth, collaboration, and innovation in various fields and industries.

Code Examples

/* 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
*/

#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}

Best Practices

When adopting and using software licensed under the GNU GPL, some best practices to follow include understanding the terms and conditions of the license, ensuring that you comply with the requirements of the GPL when distributing or modifying the software, and collaborating with the open-source community by contributing any improvements and changes back to the original project. Additionally, it is essential to provide proper attribution to the original developers and copyright holders, as well as maintaining clear documentation of any changes made to the software.

Most recommended books about GNU GPL

1. Free as in Freedom: Richard Stallman’s Crusade for Free Software (2002) by Sam Williams – This biography of Richard Stallman, the creator of GNU GPL, provides insight into the philosophy and development of the free software movement.
2. Free Software, Free Society: Selected Essays of Richard M. Stallman (2002) – A collection of essays written by Stallman discussing his views on free software, the GNU project, and the GPL.
3. Understanding Open Source and Free Software Licensing: (2004) by Andrew M. St. Laurent – A comprehensive look at various open-source licenses, including the GPL, and how they intersect with intellectual property law.

Conclusion

The GNU General Public License is a fundamental component of the free and open-source software ecosystem. It promotes innovation and collaboration by ensuring the accessibility and adaptability of licensed software, while simultaneously protecting the rights of developers and users. Understanding the ins and outs of the GPL is crucial for success in the world of open-source software, and the resources listed above can provide a solid foundation to build upon.

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