We, the free software foundation, use the gnu general public license for most of our. If you receive software under an open source license, you can always use that software for commercial purposes, but that doesnt always mean you can place further restrictions on people who receive the software from you. The gnu general public license, originally written by richard stallman, was the first copyleft license to see extensive use, and continues to dominate the licensing of copylefted software. However, an unlucky choice of wording could give it a different meaning. For example, in some countries it is acceptable to sell a software product without warranty, in standard gnu gpl style see articles 11 and 12 of the gnu gpl. The contents of this paper represent the views and opinions of the.
The license allows developers and companies to use and integrate a software component released under the lgpl into their own even proprietary software without being required by the terms of a strong copyleft license to release the source code of their own components. Richard fontana 279 words exact match in snippet view article find links to article the software freedom law center sflc. Such software must usually be passed on with a copyleft license that requires successive users to accept and transmit copyleft and mandates that any modifications or improvements to the copylefted software be likewise transmitted under copyleft. The following licenses are sorted by the number of conditions, from most gnu agplv3 to none unlicense. In particular situations, even those of us with the goal of building a world where all published software is free software realize that full copyleft does not best serve us. It was created by michael stutz after his interest in applying gnu style copyleft to nonsoftware works, which later came to be called open content. In 2012 fontana began drafting copyleft next, a modification of the gnu general public license, version 3 gplv3. I had to encode the copyleft symbol and for the sake of backwards continuity, i had to use the backwards c with combining circle method described on the wikipedia copyleft page. Anyone who receives open source software has the right to inspect and modify the code. Richard stallmans gnu manifesto turns thirty the new yorker. Most copylefted software is issued under the gnu general public license. Freesoftware dictionary definition freesoftware defined.
The most well known free software license that uses strong copyleft is the gnu general public license. The free software foundation cites some examples at gnu. Gnu ethical criteria for code repositories emphasize. The free software foundation, founded in 1985, is dedicated to promoting computer users right to use, study, copy, modify, and redistribute computer programs. The general in general public license reveals the original intent of the license, which was to provide a general solution for previous copyleft licenses associated with other gnu software, such as the gnu c compiler, glibc, and the emacs editor. For most of its history for 16 years from june 1991 to june 2007 there was really only one version of the gpl, version 2. In the gnu project, the specific distribution terms that we use are contained in the gnu general public license available in html, text, and texinfo format. Copyleft type licenses are a novel use of existing law to ensure a work remains freely available. Gnu general public license v3 gpl3 363489 code license managed by kevin. This means that you can use a library under the mitexpat license permissive in a project under the gnu gpl copyleft, and the resulting composite would be gnu gpl copyleft. A copyleft license permits embedding in a larger program only if the whole combined program is released under that license. Bear with me, but theres one more step to take before we discuss what copyleft is. Copyleft is a type of license that attempts to ensure that the public retains the freedom to use, modify, extend and redistribute a creative work and all derivative works i. Intended as an effort to develop an improved strong copyleft free software license that is.
As of 2016, the most popular free software license is the permissive mit license. The gnu general public license gnu gpl or gpl is a series of widely used free software licenses that guarantee end users the freedom to run, study, share, and modify the software. In fact, licenses are usually of such little interest that 85%of the projects on github fail to have one however, one aspect of licensing never fails to stir partisan responses. Whats the difference between permissive and copyleft. A tale of two copyleft licenses while determining the proper methodology and criteria to yield an accurate count remains difficult, the gpl is generally considered one of the most widely used free software licenses. The free software foundation prefers copyleft sharealike free software licensing rather than permissive free software licensing for most purposes. Most discussions of free software licenses bore listeners. Bsd license problem gnu project free software foundation. This is a list of software to create any kind of information graphics. Note that going in the opposite direction from copyleft to permissive is not possible. Most copylefted software is issued under the gnu general public license gpl, which was the first copyleft license and by far the most commonly used license for free software. Jun 24, 2006 most copylefted software is issued under the gnu general public license gpl, which was the first copyleft license and by far the most commonly used license for free software. Whats the difference between permissive and copyleft licenses. Examples of non copyleft free software licenses include the x11 license, apache license and the bsd licenses.
These limitations may include restricting the use of. Dap is a gnu program and is free software distributed under a gnu style copyleft. The gnu affero gpl version 3 has also been brought into the fold. Where copyleft licenses differ from socalled permissive. Free software licenses can be divided into two broad categories. Government computer software acquisition and the gnu. But he admits that the fact that gplv3 is less readily understandable than bsd style licenses might have contributed to any decline in its use. Perhaps the most significant innovation in the gnu manifesto is a method of rights protection known as copyleft, which gave rise to gnu gpl software licenses, the.
The fsf promotes the development and use of free as in freedom software particularly the gnu operating system and its gnu linux variants and. Categories of free and nonfree software gnu project free. In particular, copyleft style open source licenses require that, in at least some cases, when you distribute the software. As of 2015, mit was the most popular software license on github, ahead of any gpl variant and other free and opensource software foss licenses. Permissions of this strong copyleft license are conditioned on making. The gnu lesser general public license gnu lgpl was designed as a solution for such situations. Government computer software acquisition and the gnu general. Examples include the gnu allpermissive license, mit license, bsd licenses, apple public source license and apache license. Selling exceptions depends fundamentally on using a copyleft license, such as the gnu gpl, for the free software release. Anyone who receives open source software has the right to inspect. A permissive software license, sometimes also called bsdlike or bsd style license, is a free software license with minimal requirements about how the software can be redistributed.
Government computer software acquisition and the gnu general public license b. And a copyleft license is the safer default for authors. For example, bsd style licenses and the mit license are not. In the gnu project, our aim is to give all users the freedom to redistribute and change gnu software. Copyleft licenses such as the gnu gpl insist that modified versions of the program must be free software as well. There are thousands of pieces of free software, many of which are listed in our directory of free software, but of these projects, a few dozen are extremely common we call these the free software gang. Copyleft itself probably began in the work of mit computer expert richard stallman.
A permissive software license, sometimes also called bsdlike or bsd style license, is a freesoftware license with minimal requirements about how the software can be redistributed. According to the gnu, the founding fathers of the copyleft open source license, copyleft is a method for making a software program free, while. See how to choose a license for your own work for general recommendations about choosing a license for your work the two major categories of free software license are copyleft and non copyleft. Mar 17, 2015 perhaps the most significant innovation in the gnu manifesto is a method of rights protection known as copyleft, which gave rise to gnu gpl software licenses, the first of which was issued. The gnu general public license gnu gpl or gpl is a series of widely used free software. Free software licenses that use weak copyleft include the gnu lesser general public license and the mozilla public license. The original affero gpl was designed to ensure that all users of a web application would be able to receive its source. In the gnu project, the specific distribution terms that we use for most software are contained in the gnu general public license.
If code gets licensed under a copyleft license, authors can decide per code block, per post, per account to license it under a permissive license e. Software that can be freely copied, redistributed and modified, including source code. That would make them non copyleft free software licenses and compatible with the gnu gpl. In the united states, these licenses are supposed to be interpreted based on what the author seems to intend. Most commercial software licenses prescribe limitations on how the software may be used. You need to use css specified font control custom horizontal and vertical offsets for a specific font size. Free software is software whose source code is freely available to anyone to use for any purpose, including studying, copying, modifying, extending and giving away. Copyleft is a general concept, and you cant use a general concept directly. The tutorial is of most interest to lawyers, software developers and managers who run or advise software businesses that modify andor redistribute software under the terms of the gnu gpl or who wish to do so in the future, and those who wish to make use of existing gpld software in their enterprise. Intended as an effort to develop an improved strong copyleft free software. The usual example is gpl style restrictions, which do not allow using the code in a closedsource project except as saas. Open source licenses grant permission for anybody to use, modify, and share licensed software for any purpose, subject to conditions preserving the provenance and openness of the software. You need to use css specified font control custom horizontal and vertical offsets for. There are variations, of coursethe lgpl, for example, is a weak copyleft.
Copyleft is the idea and the specific stipulation when distributing software that the user will be able to copy it freely, examine and modify the source code, and redistribute the software to others free or priced as long as the redistributed software is also passed along with the copyleft stipulation. The mit license is a permissive free software license originating at the massachusetts institute of technology mit in the late 1980s. The gnu affero general public license3 agpl is a special license in the family of open source licenses, creating risks and opportunities that do not exist with most other open source licenses. So instead of putting gnu software in the public domain, we copyleft it. Why should the new code license be permissive instead of. Mar 14, 2019 it was created by michael stutz after his interest in applying gnu style copyleft to nonsoftware works, which later came to be called open content. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license compatibility. If middlemen could strip off the freedom, we might have many users, but those users would not have freedom. Examples of non copyleft permissive free software licenses include the x11 license, apache license and the bsd licenses. However, rms saw that using a license that gave but did not assure software freedom would be counter to the goals of the gnu project. On selling exceptions to the gnu gpl free software. It is now hosted on the free software foundation websites license list, but it is not considered compatible with the. Any software that is free of charge, such as freeware. It was created by michael stutz after his interest in applying gnu style copyleft to non software works, which later came to be called open content.
Frequently answered questions open source initiative. In the 1990s the dsl was used on music recordings, visual art, and even novels. Permissive opensource software licenses continue to gain popularity at the expense of copyleft licenses, according to a forthcoming report. I detailed analysis of the gnu gpl and related licenses.
Copyleft says that anyone who redistributes the software, with or without changes, must. More importantly, so long as both categories of licenses exist, software with a permissive license is generally unable to borrow code that uses a copyleft license, but software with a copyleft license can freely borrow code that uses a permissive license. Software freedom licenses also permit any entity to distribute modified versions of free software. Mitlicensed software can also be relicensed as proprietary software, which distinguishes it from copyleft software licenses. The gnu lesser general public license lgpl is a free software license published by the free software foundation fsf.
This part of the tutorial gives a comprehensive explanation of the most popular free software license, the gnu general public license \ gnu gpl, or sometimes just \gpl both version 2 \gplv2 and version 3 \gplv3 and teaches lawyers, software developers, managers and businesspeo. The gnu general public license is often called the gnu gpl for short. Various licenses and comments about them gnu project. Open source licenses are licenses that comply with the open source definition in brief, they allow software to be freely used, modified, and shared. Meet the free software gang free software foundation. All open source licenses, by the open source inititatives definition must, among other things, allow distribution in source form. What are some examples of sharealikecopyleft licenses. Open source licenses grant permission for anybody to use, modify, and share licensed software for any purpose, subject to conditions preserving the provenance. The licenses were originally written by richard stallman, former head of the free software foundation fsf, for the gnu project, and grant the recipients of a computer program the rights of the free software. Its list distinguishes between free software licenses that are compatible or incompatible with the fsfs copyleft gnu general public license. The licenses were originally written by richard stallman, former head of the free software foundation fsf, for the gnu project, and grant the recipients of a.