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<title>The Free Software Definition - GNU Project - Free Software Foundation (FSF)</title> |
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<meta http-equiv="Keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" /> |
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<meta http-equiv="Description" content="Since 1983, developing the free Unix style operating system GNU, so that computer users can have the freedom to share and improve the software they use." /> |
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<h1>The Free Software Definition</h1> |
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|
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<p> |
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We maintain this free software definition to show clearly what must |
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be true about a particular software program for it to be considered |
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free software. |
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</p> |
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|
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<p> |
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<q>Free software</q> is a matter of liberty, not price. To understand |
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the concept, you should think of <q>free</q> as in <q>free speech,</q> |
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not as in <q>free beer.</q> |
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</p> |
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|
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<p> |
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Free software is a matter of the users' freedom to run, copy, distribute, |
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study, change and improve the software. More precisely, it refers to |
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four kinds of freedom, for the users of the software: |
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</p> |
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|
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<ul> |
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<li>The freedom to run the program, for any purpose (freedom 0).</li> |
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<li>The freedom to study how the program works, and adapt it to |
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your needs (freedom 1). Access to the source code is a precondition |
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for this. |
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</li> |
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<li>The freedom to redistribute copies so you can help your neighbor |
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(freedom 2). |
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</li> |
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<li>The freedom to improve the program, and release your improvements |
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to the public, so that the whole community benefits (freedom 3). |
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Access to the source code is a precondition for this. |
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</li> |
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</ul> |
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|
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<p> |
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A program is free software if users have all of these freedoms. Thus, |
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you should be free to redistribute copies, either with or without |
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modifications, either gratis or charging a fee for distribution, to |
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<a href="#exportcontrol">anyone anywhere</a>. Being free to do these |
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things means (among other things) that you do not have to ask or pay |
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for permission. |
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</p> |
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|
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<p> |
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You should also have the freedom to make modifications and use them |
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privately in your own work or play, without even mentioning that they |
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exist. If you do publish your changes, you should not be required to |
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notify anyone in particular, or in any particular way. |
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</p> |
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|
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<p> |
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The freedom to run the program means the freedom for any kind of person |
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or organization to use it on any kind of computer system, for any kind of |
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overall job and purpose, without being required to communicate about it |
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with the developer or any other specific entity. In this freedom, it is |
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the <em>user's</em> purpose that matters, not the <em>developer's</em> |
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purpose; you as a user are free to run a program for your purposes, |
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and if you distribute it to someone else, she is then free to run it |
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for her purposes, but you are not entitled to impose your purposes on her. |
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</p> |
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|
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<p> |
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The freedom to redistribute copies must include binary or executable |
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forms of the program, as well as source code, for both modified and |
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unmodified versions. (Distributing programs in runnable form is necessary |
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for conveniently installable free operating systems.) It is ok if there |
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is no way to produce a binary or executable form for a certain program |
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(since some languages don't support that feature), but you must have the |
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freedom to redistribute such forms should you find or develop a way to |
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make them. |
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</p> |
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|
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<p> |
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In order for the freedoms to make changes, and to publish improved |
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versions, to be meaningful, you must have access to the source code of |
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the program. Therefore, accessibility of source code is a necessary |
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condition for free software. |
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</p> |
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|
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<p> |
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One important way to modify a program is by merging in available |
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free subroutines and modules. If the program's license says that you |
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cannot merge in an existing module, such as if it requires you to be the |
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copyright holder of any code you add, then the license is too restrictive |
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to qualify as free. |
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</p> |
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|
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<p> |
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In order for these freedoms to be real, they must be irrevocable as |
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long as you do nothing wrong; if the developer of the software has the |
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power to revoke the license, without your doing anything to give cause, |
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the software is not free. |
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</p> |
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|
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<p> |
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However, certain kinds of rules about the manner of distributing free |
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software are acceptable, when they don't conflict with the central |
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freedoms. For example, copyleft (very simply stated) is the rule that |
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when redistributing the program, you cannot add restrictions to deny |
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other people the central freedoms. This rule does not conflict with |
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the central freedoms; rather it protects them. |
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</p> |
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|
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<p> |
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You may have paid money to get copies of free software, or you may have |
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obtained copies at no charge. But regardless of how you got your copies, |
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you always have the freedom to copy and change the software, even to |
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<a href="/philosophy/selling.html">sell copies</a>. |
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</p> |
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|
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<p> |
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<q>Free software</q> does not mean <q>non-commercial.</q> A free |
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program must be available for commercial use, commercial development, |
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and commercial distribution. Commercial development of free software |
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is no longer unusual; such free commercial software is very important. |
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</p> |
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|
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<p> |
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Rules about how to package a modified version are acceptable, if they |
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don't substantively block your freedom to release modified versions, or |
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your freedom to make and use modified versions privately. Rules that <q>if |
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you make your version available in this way, you must make it available in |
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that way also</q> can be acceptable too, on the same condition. (Note that |
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such a rule still leaves you the choice of whether to publish your version |
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at all.) Rules that require release of source code to the users for |
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versions that you put into public use are also acceptable. It is also |
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acceptable for the license to require that, if you have distributed a |
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modified version and a previous developer asks for a copy of it, you |
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must send one, or that you identify yourself on your modifications. |
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</p> |
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|
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<p> |
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In the GNU project, we use |
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<q><a href="/copyleft/copyleft.html">copyleft</a></q> |
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to protect these freedoms legally for everyone. But |
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<a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">non-copylefted |
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free software</a> also exists. We believe there are important reasons why |
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<a href="/philosophy/pragmatic.html"> it is better to use copyleft</a>, |
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but if your program is non-copylefted free software, we can still |
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use it. |
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</p> |
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|
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<p> |
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See <a href="/philosophy/categories.html">Categories of Free Software</a> |
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for a description of how <q>free software,</q> <q>copylefted software</q> |
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and other categories of software relate to each other. |
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</p> |
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|
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<p> |
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Sometimes government <a id="exportcontrol">export control regulations</a> |
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and trade sanctions can constrain your freedom to distribute copies of |
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programs internationally. Software developers do not have the power to |
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eliminate or override these restrictions, but what they can and must do |
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is refuse to impose them as conditions of use of the program. In this |
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way, the restrictions will not affect activities and people outside the |
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jurisdictions of these governments. |
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</p> |
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|
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<p> |
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Most free software licenses are based on copyright, and there are limits |
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on what kinds of requirements can be imposed through copyright. If a |
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copyright-based license respects freedom in the ways described above, it |
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is unlikely to have some other sort of problem that we never anticipated |
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(though this does happen occasionally). However, some free software |
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licenses are based on contracts, and contracts can impose a much larger |
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range of possible restrictions. That means there are many possible ways |
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such a license could be unacceptably restrictive and non-free. |
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</p> |
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|
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<p> |
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We can't possibly list all the ways that might happen. If a |
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contract-based license restricts the user in an unusual way that |
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copyright-based licenses cannot, and which isn't mentioned here as |
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legitimate, we will have to think about it, and we will probably conclude |
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it is non-free. |
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</p> |
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|
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<p> |
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When talking about free software, it is best to avoid using terms |
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like <q>give away</q> or <q>for free,</q> because those terms imply that |
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the issue is about price, not freedom. Some common terms such |
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as <q>piracy</q> embody opinions we hope you won't endorse. See |
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<a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that |
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are Worth Avoiding</a> for a discussion of these terms. We also have |
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a list of <a href="/philosophy/fs-translations.html">translations of |
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<q>free software</q></a> into various languages. |
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</p> |
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|
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<p> |
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Finally, note that criteria such as those stated in this free software |
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definition require careful thought for their interpretation. To decide |
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whether a specific software license qualifies as a free software license, |
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we judge it based on these criteria to determine whether it fits their |
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spirit as well as the precise words. If a license includes unconscionable |
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restrictions, we reject it, even if we did not anticipate the issue |
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in these criteria. Sometimes a license requirement raises an issue |
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that calls for extensive thought, including discussions with a lawyer, |
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before we can decide if the requirement is acceptable. When we reach |
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a conclusion about a new issue, we often update these criteria to make |
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it easier to see why certain licenses do or don't qualify. |
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</p> |
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|
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<p> |
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If you are interested in whether a specific license qualifies as a free |
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software license, see our <a href="/licenses/license-list.html">list |
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of licenses</a>. If the license you are concerned with is not |
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listed there, you can ask us about it by sending us email at |
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<a href="mailto:licensing@gnu.org"><licensing@gnu.org></a>. |
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</p> |
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|
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<p> |
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If you are contemplating writing a new license, please contact the FSF |
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by writing to that address. The proliferation of different free software |
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licenses means increased work for users in understanding the licenses; |
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we may be able to help you find an existing Free Software license that |
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meets your needs. |
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</p> |
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|
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<p> |
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If that isn't possible, if you really need a new license, with our |
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help you can ensure that the license really is a Free Software license |
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and avoid various practical problems. |
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</p> |
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|
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<h2 id="beyond-software">Beyond Software</h2> |
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|
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<p> |
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<a href="/philosophy/free-doc.html">Software manuals must be free</a>, |
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for the same reasons that software must be free, and because the |
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manuals are in effect part of the software. |
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</p> |
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|
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<p> |
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The same arguments also make sense for other kinds of works of |
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practical use — that is to say, works that embody useful knowledge, |
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such as educational works and reference |
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works. <a href="http://wikipedia.org">Wikipedia</a> is the best known |
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example. |
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</p> |
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|
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<p> |
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Any kind of work <em>can</em> be free, and the definition of free software |
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has been extended to a definition of <a href="http://freedomdefined.org/"> |
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free cultural works</a> applicable to any kind of works. |
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</p> |
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|
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<h2 id="open-source">Open Source?</h2> |
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|
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<p> |
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Another group has started using the term <q>open source</q> to mean |
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something close (but not identical) to <q>free software.</q> We |
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prefer the term <q>free software</q> because, once you have heard that |
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it refers to freedom rather than price, it calls to mind freedom. The |
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word <q>open</q> <a href="/philosophy/open-source-misses-the-point.html"> |
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never refers to freedom</a>. |
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</p> |
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|
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</div> |
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|
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|
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<!--#include virtual="/server/footer.html" --> |
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<div id="footer"> |
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<p> |
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Please send FSF & GNU inquiries to |
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<a href="mailto:gnu@gnu.org"><em>gnu@gnu.org</em></a>. |
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There are also <a href="http://www.fsf.org/about/contact.html">other ways to contact</a> |
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the FSF. |
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<br /> |
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Please send broken links and other corrections (or suggestions) to |
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<a href="mailto:webmasters@gnu.org"><em>webmasters@gnu.org</em></a>. |
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</p> |
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|
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<p> |
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Please see the |
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<a href="/server/standards/README.translations.html">Translations |
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README</a> for information on coordinating and submitting |
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translations of this article. |
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</p> |
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|
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<p> |
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Copyright © 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, |
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2005, 2006, 2007 Free Software Foundation, Inc., |
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</p> |
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<address>51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA</address> |
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<p>Verbatim copying and distribution of this entire article is |
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permitted in any medium without royalty provided this notice is |
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preserved. |
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</p> |
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|
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<p> |
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Updated: |
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<!-- timestamp start --> |
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$Date: 2007/04/09 20:46:36 $ |
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<!-- timestamp end --> |
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</p> |
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</div> |
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|
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<div id="translations"> |
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<h4>Translations of this page</h4> |
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