Understanding open source licenses

Open source licenses are licenses that comply with the Open Source Definition — in brief, they allow software to be freely used, modified, and shared. To be approved by the Open Source Initiative (also known as the OSI), a license must go through the Open Source Initiative’s license review process.

There has been an increase release of open source software from the day of Linux. Today most popular frame works like bootstrap and software such as Atom IDE used by developers are open source. We often never worry about using open source code but do you know what the license under which the frame you’re using was released means?

A list of all open source licenses.

• Apache License 2.0
• BSD 3-Clause “New” or “Revised” license
• BSD 2-Clause “Simplified” or “FreeBSD” license
• GNU General Public License (GPL)
• GNU Library or “Lesser” General Public License (LGPL)
• MIT license
• Mozilla Public License 2.0
• Common Development and Distribution License
• Eclipse Public License

The MIT license, GNU (GPL), the BSD 2 and the Apache license 2.0 are the most used open source licenses in that order.

Open source software and source code can be used for commercial purposes *almost* (see comment below) in all the open source licenses. However, note that commercial is not the same as proprietary. If you receive software under an Open Source license, you can always use that software for commercial purposes, but that doesn’t always mean you can place further restrictions on people who receive the software from you.

Copy Left

Another factor associated with open source code notably under the GNU license is copy-left. “Copyleft” refers to licenses that allow derivative works but require them to use the same license as the original work. For example, if you write some software and release it under the GNU General Public License (a widely-used copyleft license), and then someone else modifies that software and distributes their modified version, the modified version must be licensed under the GNU GPL too — including any new code written specifically to go into the modified version. Both the original and the new work are Open Source; the copyleft license simply ensures that property is perpetuated to all downstream derivatives. There also non copy left licenses like the BSD.

BSD and other such licenses that don’t allow for copy left and guarantee the freedoms to use, modify, and redistribute, but that permit proprietary derivative works are called permissive” Open Source license

There is software that is released under the Creative Commons “CC0” (“CC Zero”) like the C GNU compiler. The CCO is not an open source license but rather essentially a statement of intent by the copyright holder to waive copyright ownership in the work — that is, the copyright holder wishes to place the work into the public domain.

As developers it’s important that you understand the license the open source code you’re using is bound to least you caught in a legal battle after your product becomes a big thing.