The GNU General Public License (GPL) is a widely used free software license that allows developers to use, modify, and distribute software while ensuring that it remains free for all users. Created by the Free Software Foundation (FSF), the GPL is designed to promote software freedom and collaboration. When a piece of software is licensed under the GPL, anyone can run it for any purpose, study its internal workings, modify it, and share those modifications. However, if someone distributes the modified software, they must do so under the same GPL license, which ensures that the freedoms associated with the original software are preserved.
One of the key principles of the GPL is the concept of "copyleft." This means that any derivative work must also be licensed under the GPL, preventing proprietary use of the software. For example, if a developer takes a GPL-licensed project, makes enhancements, and releases it, they must also distribute the enhancements under the GPL. This creates a strong community of collaboration and sharing, where improvements made by one developer benefit all users of the software. Prominent examples of software licensed under the GPL include the Linux operating system kernel and the GNU Core Utilities.
It's important for developers to understand the implications of using GPL-licensed software in their projects. If your project incorporates GPL-licensed code, you need to comply with its terms, which might involve releasing your own project's source code under the GPL if you distribute it. This requirement can impact how you develop your software, especially if you're considering monetizing it. Developers should carefully review the license terms and evaluate whether the GPL aligns with their project's goals before using GPL-licensed components.