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<title>The Free Software Definition - GNU Project - Free Software Foundation (FSF)</title> |
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<p><a href="#translations">Translations</a> of this page</p> |
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|
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<h3>The Free Software Definition</h3> |
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<p> |
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<a href="/graphics/philosophicalgnu.html"><img src="/graphics/philosophical-gnu-sm.jpg" alt=" [image of a Philosophical Gnu] " width="160" height="200" /></a> |
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</p> |
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|
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<p> |
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We maintain this free software definition to show clearly what must be |
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true about a particular software program for it to be considered |
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free software.</p> |
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<p> |
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``Free software'' is a matter of liberty, not price. To understand the |
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concept, you should think of ``free'' as in ``free speech,'' not as in |
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``free beer.''</p> |
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<p> |
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Free software is a matter of the users' freedom to run, copy, |
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distribute, study, change and improve the software. More precisely, |
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it refers to four kinds of freedom, for the users of the software:</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 your needs |
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(freedom 1). Access to the source code is a precondition for this.</li> |
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<li>The freedom to redistribute copies so you can help your neighbor |
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(freedom 2).</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 |
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(freedom 3). Access to the source code is a precondition for this.</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. |
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Thus, you should be free to redistribute copies, either with or |
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without modifications, either gratis or charging a fee for |
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distribution, to <a href="#exportcontrol">anyone anywhere</a>. Being |
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free to do these things means (among other things) that you do not |
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have to ask or pay for permission.</p> |
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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.</p> |
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<p> |
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The freedom to use a 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 |
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of overall job, and without being required to communicate subsequently |
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with the developer or any other specific entity.</p> |
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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 |
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necessary for conveniently installable free operating systems.) It is |
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ok if there is no way to produce a binary or executable form for a |
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certain program (since some languages don't support that feature), but |
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you must have the freedom to redistribute such forms should you find |
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or develop a way to make them.</p> |
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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.</p> |
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<p> |
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One important way to modify a program is by merging in available free |
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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 |
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the copyright holder of any code you add, then the license is too |
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restrictive to qualify as free.</p> |
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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 |
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cause, the software is not free.</p> |
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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.</p> |
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<p> |
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You may have paid money to get copies of free software, or you |
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may have obtained copies at no charge. But regardless of how you got |
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your copies, you always have the freedom to copy and change the |
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software, even to <a href="/philosophy/selling.html">sell copies</a>.</p> |
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<p> |
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``Free software'' does not mean ``non-commercial''. A free program |
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must be available for commercial use, commercial development, and |
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commercial distribution. Commercial development of free software is |
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no longer unusual; such free commercial software is very important.</p> |
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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, |
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or your freedom to make and use modified versions privately. Rules |
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that ``if you make your version available in this way, you must make |
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it available in that way also'' can be acceptable too, on the same |
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condition. (Note that such a rule still leaves you the choice of |
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whether to publish your version at all.) Rules that require release |
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of source code to the users for versions that you put into public use |
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are also acceptable. It is also acceptable for the license to require |
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that, if you have distributed a modified version and a previous |
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developer asks for a copy of it, you must send one, or that you |
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identify yourself on your modifications. |
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</p> |
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<p> |
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In the GNU project, we use <a href="/copyleft/copyleft.html">``copyleft''</a> |
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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 |
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important reasons why <a href="/philosophy/pragmatic.html"> it is |
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better to use copyleft</a>, but if your program is non-copylefted free |
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software, we can still use it.</p> |
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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 ``free software,'' ``copylefted software'' and |
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other categories of software relate to each other.</p> |
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<p> |
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Sometimes government <a id="exportcontrol">export control |
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regulations</a> and trade sanctions can constrain your freedom to |
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distribute copies of programs internationally. Software developers do |
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not have the power to eliminate or override these restrictions, but |
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what they can and must do is refuse to impose them as conditions of |
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use of the program. In this way, the restrictions will not affect |
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activities and people outside the jurisdictions of these governments.</p> |
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<p> |
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Most free software licenses are based on copyright, and there are |
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limits on what kinds of requirements can be imposed through copyright. |
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If a copyright-based license respects freedom in the ways described |
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above, it is unlikely to have some other sort of problem that we never |
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anticipated (though this does happen occasionally). However, some |
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free software licenses are based on contracts, and contracts can |
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impose a much larger range of possible restrictions. That means there |
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are many possible ways such a license could be unacceptably |
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restrictive and non-free.</p> |
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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 |
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conclude it is non-free.</p> |
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<p> |
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When talking about free software, it is best to avoid using terms like |
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``give away'' or ``for free'', because those terms imply that the |
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issue is about price, not freedom. Some common terms such as |
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``piracy'' embody opinions we hope you won't endorse. See |
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<a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases |
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that are Worth Avoiding</a> for a discussion of these terms. |
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We also have a list of <a href="/philosophy/fs-translations.html">translations |
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of "free software"</a> into various languages.</p> |
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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 |
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decide whether a specific software license qualifies as a free |
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software license, we judge it based on these criteria to determine |
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whether it fits their spirit as well as the precise words. If a |
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license includes unconscionable restrictions, we reject it, even if we |
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did not anticipate the issue in these criteria. Sometimes a license |
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requirement raises an issue that calls for extensive thought, |
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including discussions with a lawyer, before we can decide if the |
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requirement is acceptable. When we reach a conclusion about a new |
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issue, we often update these criteria to make it easier to see why |
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certain licenses do or don't qualify.</p> |
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<p> |
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If you are interested in whether a specific license qualifies as a |
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free software license, see our <a |
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href="/licenses/license-list.html">list of licenses</a>. If the |
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license you are concerned with is not listed there, you can ask us |
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about it by sending us email at <a |
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href="mailto:licensing@gnu.org"><licensing@gnu.org></a>.</p> <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 |
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software licenses means increased work for users in understanding the |
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licenses; we may be able to help you find an existing Free Software |
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license that 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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<hr /> |
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|
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<p> |
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Another group has started using the term "open source" to mean |
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something close (but not identical) to "free software". We prefer the |
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term "free software" because, once you have heard it refers to freedom |
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rather than price, <a href="free-software-for-freedom.html">it calls |
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to mind freedom</a>. The word "open" never does that.</p> |
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|
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<hr /> |
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<h4><a href="/philosophy/philosophy.html">Other Texts to Read</a></h4> |
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<b>Translations of this page</b>:<br /> |
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<a href="/philosophy/free-sw.ca.html">Català</a> <!-- Catalan --> |
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| <a href="/philosophy/free-sw.cn.html">简体中文</a> |
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| <a href="/philosophy/free-sw.ko.html">한국어</a> <!-- Korean --> |
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| <a href="/philosophy/free-sw.hu.html">Magyar</a> <!-- Hungarian --> |
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| <a href="/philosophy/free-sw.nl.html">Nederlands</a> <!-- Dutch --> |
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| <a href="/philosophy/free-sw.no.html">Norsk</a> <!-- Norwegian --> |
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| <a href="/philosophy/free-sw.pl.html">Polski</a> <!-- Polish --> |
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| <a href="/philosophy/free-sw.pt.html">Português</a> <!-- Portuguese --> |
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| <a href="/philosophy/free-sw.sl.html">Slovinsko</a> <!--- Slovenian --> |
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| <a href="/philosophy/free-sw.sr.html">Српски</a> <!-- Serbian --> |
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| <a href="/philosophy/free-sw.tl.html">Tagalog</a> <!-- Tagalog --> |
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| <a href="/philosophy/free-sw.tr.html">Türkçe</a> <!-- Turkish --> |
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] |
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</p> |
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</div> |
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|
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<div class="copyright"> |
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<p> |
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Return to the <a href="/home.html">GNU Project home page</a>. |
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</p> |
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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="/home.html#ContactInfo">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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<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 (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free |
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Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA |
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02110, USA |
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<br /> |
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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: 2005/11/26 13:16:40 $ $Author: rms $ |
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<!-- timestamp end --> |
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