|Debian FSG compatible||Yes|
|FSF approved||Yes (see "informal license" section)|
|Linking from code with a different licence||Yes|
Beerware is a somewhat tongue-in-cheek term for software released under a very relaxed license (beerware licensed software). It provides the end user with the right to use a particular program (or do anything else with the source code).
Should the user of the product meet the author and consider the software useful, they are encouraged to either buy the author a beer "in return" or drink one themselves. The Fedora project and Humanitarian-FOSS project at Trinity College recognized the "version 42" beerware license variant as extremely permissive "copyright only" license, and consider it as GPL compatible. As of 2016 [update] the Free Software Foundation does not mention this license explicitly, but its list of licenses contains an entry for informal licenses, which are listed as free, non-copyleft, and GPL-compatible. However, the FSF recommends the use of more detailed licenses over informal ones.
Many variations on the beerware model have been created. Poul-Henning Kamp's beerware license is simple and short, in contrast to the GPL, which he has described as a "joke".The full text of Kamp's license is:
/* * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you * can do whatever you want with this stuff. If we meet some day, and you think * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp * ---------------------------------------------------------------------------- */
Free software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price: users and computer programmers are free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give both programmers and end-users ultimate control over the software and, subsequently, over their devices.
The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedom to run the software, to study the software, to modify the software, to share possibly modified copies of the software. Software which meets these requirements is termed free software. The word 'free' is ambiguous in English, although in this context, it means 'free as in freedom', not 'free as in zero price'. A common example is, "to think of free speech, not free beer."
The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties. The ASF and its projects release their software products under the Apache License. The license is also used by many non-ASF projects.
A software license is a legal instrument governing the use or redistribution of software. Under United States copyright law, all software is copyright protected, in both source code and object code forms, unless that software was developed by the United States Government, in which case it cannot be copyrighted. Authors of copyrighted software can donate their software to the public domain, in which case it is also not covered by copyright and, as a result, cannot be licensed.
The Common Development and Distribution License (CDDL) is a free and open-source software license, produced by Sun Microsystems, based on the Mozilla Public License (MPL). Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary. In 2005 the Open Source Initiative approved the license. The Free Software Foundation (FSF) considers it a free software license, but one which is incompatible with the GNU General Public License (GPL).
Free and open-source software (FOSS) is software that can be classified as both free software and open-source software. That is, anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.
Poul-Henning Kamp is a Danish computer software developer known for work on various projects. He currently resides in Slagelse, Denmark.
Free/open-source software – the source availability model used by free and open-source software (FOSS) – and closed source are two approaches to the distribution of software.
A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license with only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. As of 2016, the most popular free-software license is the permissive MIT license.
Alternative terms for free software, such as open source, FOSS, and FLOSS, have been a controversial issue among free and open-source software users from the late 1990s onwards. These terms share almost identical licence criteria and development practices.
This is a comparison of free and open-source software licences. The comparison only covers software licences with a linked article for details, approved by at least one expert group at the FSF, the OSI, the Debian project or the Fedora project. For a list of licences not specifically intended for software, see List of free content licences.
WTFPL is a GPL-compatible permissive license most commonly used as a free software license. As a public domain like license, the WTFPL is essentially the same as dedication to the public domain. It allows redistribution and modification of the work under any terms. The title is an abbreviation of "Do What The Fuck You Want To Public License".
Public-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses.
License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem negatively by the burden of increasingly complex license selection, license interaction, and license compatibility considerations.
License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.
A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.
BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.
The GNU General Public License is a series of widely used free software licenses that guarantee end users the freedom to run, study, share, and modify the software. 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 Definition. The GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. This is in distinction to permissive software licenses, of which the BSD licenses and the MIT License are widely used, less restrictive examples. GPL was the first copyleft license for general use.
Software relicensing is applied in open-source software development when software licenses of software modules are incompatible and are required to be compatible for a greater combined work. Licenses applied to software as copyrightable works, in source code as binary form, can contain contradictory clauses. These requirements can make it impossible to combine source code or content of several software works to create a new combined one.
The GNU All-permissive License is a lax, permissive (non-copyleft) free software license, compatible with the GNU General Public License, recommended by the Free Software Foundation for README and other small supporting files.
The license is compatible with proprietary licenses and the GNU GPL, as code under this license has no restrictions whatsoever.