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<title>The Free Software Definition - GNU Project - Free Software Foundation (FSF)</title> |
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The Free Software Definition - GNU Project - Free Software Foundation (FSF) |
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<a href="http://www.defectivebydesign.org/join/gnu"><img src="/graphics/dbd.png" alt="[Join the FSF Campaign to Eliminate DRM]" /></a> |
<a href="http://www.defectivebydesign.org/join/gnu"> |
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alt="[Join the FSF Campaign to Eliminate DRM]" /> |
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<h3>The Free Software Definition</h3> |
<h3>The Free Software Definition</h3> |
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<p> |
<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> |
<p> |
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We maintain this free software definition to show clearly what must be |
We maintain this free software definition to show clearly what must |
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true about a particular software program for it to be considered |
be true about a particular software program for it to be considered |
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free software.</p> |
free software. |
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</p> |
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<p> |
<p> |
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``Free software'' is a matter of liberty, not price. To understand the |
<q>Free software</q> is a matter of liberty, not price. To understand |
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concept, you should think of ``free'' as in ``free speech,'' not as in |
the concept, you should think of <q>free</q> as in <q>free speech,</q> |
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``free beer.''</p> |
not as in <q>free beer.</q> |
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</p> |
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<p> |
<p> |
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Free software is a matter of the users' freedom to run, copy, |
Free software is a matter of the users' freedom to run, copy, distribute, |
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distribute, study, change and improve the software. More precisely, |
study, change and improve the software. More precisely, it refers to |
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it refers to four kinds of freedom, for the users of the software:</p> |
four kinds of freedom, for the users of the software: |
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</p> |
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<ul> |
<ul> |
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<li>The freedom to run the program, for any purpose (freedom 0).</li> |
<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 |
<li>The freedom to study how the program works, and adapt it to |
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(freedom 1). Access to the source code is a precondition for this.</li> |
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 |
<li>The freedom to redistribute copies so you can help your neighbor |
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(freedom 2).</li> |
(freedom 2). |
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</li> |
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<li>The freedom to improve the program, and release your improvements |
<li>The freedom to improve the program, and release your improvements |
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to the public, so that the whole community benefits |
to the public, so that the whole community benefits (freedom 3). |
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(freedom 3). Access to the source code is a precondition for this.</li> |
Access to the source code is a precondition for this. |
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</li> |
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</ul> |
</ul> |
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<p> |
<p> |
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A program is free software if users have all of these freedoms. |
A program is free software if users have all of these freedoms. Thus, |
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Thus, you should be free to redistribute copies, either with or |
you should be free to redistribute copies, either with or without |
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without modifications, either gratis or charging a fee for |
modifications, either gratis or charging a fee for distribution, to |
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distribution, to <a href="#exportcontrol">anyone anywhere</a>. Being |
<a href="#exportcontrol">anyone anywhere</a>. Being free to do these |
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free to do these things means (among other things) that you do not |
things means (among other things) that you do not have to ask or pay |
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have to ask or pay for permission.</p> |
for permission. |
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</p> |
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<p> |
<p> |
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You should also have the freedom to make modifications and use them |
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 |
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 |
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> |
notify anyone in particular, or in any particular way. |
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</p> |
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<p> |
<p> |
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The freedom to run the program means the freedom for any kind of |
The freedom to run the program means the freedom for any kind of person |
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person or organization to use it on any kind of computer system, for |
or organization to use it on any kind of computer system, for any kind of |
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any kind of overall job and purpose, without being required to |
overall job and purpose, without being required to communicate about it |
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communicate about it with the developer or any other specific entity. |
with the developer or any other specific entity. In this freedom, it is |
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In this freedom, it is the <em>user's</em> purpose that matters, not |
the <em>user's</em> purpose that matters, not the <em>developer's</em> |
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the <em>developer's</em> purpose; you as a user are free to run a |
purpose; you as a user are free to run a program for your purposes, |
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program for your purposes, and if you distribute it to someone else, |
and if you distribute it to someone else, she is then free to run it |
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she is then free to run it for her purposes, but you are not entitled |
for her purposes, but you are not entitled to impose your purposes on her. |
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to impose your purposes on her. |
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</p> |
</p> |
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<p> |
<p> |
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The freedom to redistribute copies must include binary or executable |
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 |
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 |
unmodified versions. (Distributing programs in runnable form is necessary |
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necessary for conveniently installable free operating systems.) It is |
for conveniently installable free operating systems.) It is ok if there |
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ok if there is no way to produce a binary or executable form for a |
is no way to produce a binary or executable form for a certain program |
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certain program (since some languages don't support that feature), but |
(since some languages don't support that feature), but you must have the |
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you must have the freedom to redistribute such forms should you find |
freedom to redistribute such forms should you find or develop a way to |
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or develop a way to make them.</p> |
make them. |
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</p> |
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<p> |
<p> |
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In order for the freedoms to make changes, and to publish improved |
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 |
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 |
the program. Therefore, accessibility of source code is a necessary |
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condition for free software.</p> |
condition for free software. |
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</p> |
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<p> |
<p> |
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One important way to modify a program is by merging in available free |
One important way to modify a program is by merging in available |
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subroutines and modules. If the program's license says that you |
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 |
cannot merge in an existing module, such as if it requires you to be the |
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the copyright holder of any code you add, then the license is too |
copyright holder of any code you add, then the license is too restrictive |
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restrictive to qualify as free.</p> |
to qualify as free. |
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<p> |
<p> |
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In order for these freedoms to be real, they must be irrevocable as |
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 |
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 |
power to revoke the license, without your doing anything to give cause, |
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cause, the software is not free.</p> |
the software is not free. |
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</p> |
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<p> |
<p> |
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However, certain kinds of rules about the manner of distributing free |
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 |
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 |
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 |
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 |
other people the central freedoms. This rule does not conflict with |
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the central freedoms; rather it protects them.</p> |
the central freedoms; rather it protects them. |
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</p> |
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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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<p> |
<p> |
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You may have paid money to get copies of free software, or you |
<q>Free software</q> does not mean <q>non-commercial.</q> A free |
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may have obtained copies at no charge. But regardless of how you got |
program must be available for commercial use, commercial development, |
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your copies, you always have the freedom to copy and change the |
and commercial distribution. Commercial development of free software |
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software, even to <a href="/philosophy/selling.html">sell copies</a>.</p> |
is no longer unusual; such free commercial software is very important. |
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<p> |
</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> |
<p> |
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Rules about how to package a modified version are acceptable, if they |
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, |
don't substantively block your freedom to release modified versions, or |
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or your freedom to make and use modified versions privately. Rules |
your freedom to make and use modified versions privately. Rules that <q>if |
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that ``if you make your version available in this way, you must make |
you make your version available in this way, you must make it available in |
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it available in that way also'' can be acceptable too, on the same |
that way also</q> can be acceptable too, on the same condition. (Note that |
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condition. (Note that such a rule still leaves you the choice of |
such a rule still leaves you the choice of whether to publish your version |
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whether to publish your version at all.) Rules that require release |
at all.) Rules that require release of source code to the users for |
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of source code to the users for versions that you put into public use |
versions that you put into public use are also acceptable. It is also |
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are also acceptable. It is also acceptable for the license to require |
acceptable for the license to require that, if you have distributed a |
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that, if you have distributed a modified version and a previous |
modified version and a previous developer asks for a copy of it, you |
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developer asks for a copy of it, you must send one, or that you |
must send one, or that you identify yourself on your modifications. |
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identify yourself on your modifications. |
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</p> |
</p> |
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<p> |
<p> |
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In the GNU project, we use <a href="/copyleft/copyleft.html">``copyleft''</a> |
In the GNU project, we use |
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to protect these freedoms legally for everyone. But |
<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 |
<a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">non-copylefted |
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free software</a> also exists. We believe there are |
free software</a> also exists. We believe there are important reasons why |
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important reasons why <a href="/philosophy/pragmatic.html"> it is |
<a href="/philosophy/pragmatic.html"> it is better to use copyleft</a>, |
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better to use copyleft</a>, but if your program is non-copylefted free |
but if your program is non-copylefted free software, we can still |
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software, we can still use it.</p> |
use it. |
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</p> |
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<p> |
<p> |
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See <a href="/philosophy/categories.html">Categories of Free Software</a> |
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 |
for a description of how <q>free software,</q> <q>copylefted software</q> |
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other categories of software relate to each other.</p> |
and other categories of software relate to each other. |
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</p> |
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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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<p> |
<p> |
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Sometimes government <a id="exportcontrol">export control |
Most free software licenses are based on copyright, and there are limits |
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regulations</a> and trade sanctions can constrain your freedom to |
on what kinds of requirements can be imposed through copyright. If a |
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distribute copies of programs internationally. Software developers do |
copyright-based license respects freedom in the ways described above, it |
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not have the power to eliminate or override these restrictions, but |
is unlikely to have some other sort of problem that we never anticipated |
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what they can and must do is refuse to impose them as conditions of |
(though this does happen occasionally). However, some free software |
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use of the program. In this way, the restrictions will not affect |
licenses are based on contracts, and contracts can impose a much larger |
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activities and people outside the jurisdictions of these governments.</p> |
range of possible restrictions. That means there are many possible ways |
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<p> |
such a license could be unacceptably restrictive and non-free. |
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Most free software licenses are based on copyright, and there are |
</p> |
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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> |
<p> |
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We can't possibly list all the ways that might happen. If a |
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 |
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 |
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 |
legitimate, we will have to think about it, and we will probably conclude |
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conclude it is non-free.</p> |
it is non-free. |
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</p> |
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<p> |
<p> |
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When talking about free software, it is best to avoid using terms like |
When talking about free software, it is best to avoid using terms |
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``give away'' or ``for free'', because those terms imply that the |
like <q>give away</q> or <q>for free,</q> because those terms imply that |
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issue is about price, not freedom. Some common terms such as |
the issue is about price, not freedom. Some common terms such |
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``piracy'' embody opinions we hope you won't endorse. See |
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 |
<a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that |
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that are Worth Avoiding</a> for a discussion of these terms. |
are Worth Avoiding</a> for a discussion of these terms. We also have |
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We also have a list of <a href="/philosophy/fs-translations.html">translations |
a list of <a href="/philosophy/fs-translations.html">translations of |
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of "free software"</a> into various languages.</p> |
<q>free software</q></a> into various languages. |
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</p> |
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<p> |
<p> |
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Finally, note that criteria such as those stated in this free software |
Finally, note that criteria such as those stated in this free software |
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definition require careful thought for their interpretation. To |
definition require careful thought for their interpretation. To decide |
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decide whether a specific software license qualifies as a free |
whether a specific software license qualifies as a free software license, |
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software license, we judge it based on these criteria to determine |
we judge it based on these criteria to determine whether it fits their |
| 234 |
whether it fits their spirit as well as the precise words. If a |
spirit as well as the precise words. If a license includes unconscionable |
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license includes unconscionable restrictions, we reject it, even if we |
restrictions, we reject it, even if we did not anticipate the issue |
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did not anticipate the issue in these criteria. Sometimes a license |
in these criteria. Sometimes a license requirement raises an issue |
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requirement raises an issue that calls for extensive thought, |
that calls for extensive thought, including discussions with a lawyer, |
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including discussions with a lawyer, before we can decide if the |
before we can decide if the requirement is acceptable. When we reach |
| 239 |
requirement is acceptable. When we reach a conclusion about a new |
a conclusion about a new issue, we often update these criteria to make |
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issue, we often update these criteria to make it easier to see why |
it easier to see why certain licenses do or don't qualify. |
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certain licenses do or don't qualify.</p> |
</p> |
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<p> |
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If you are interested in whether a specific license qualifies as a |
<p> |
| 244 |
free software license, see our <a |
If you are interested in whether a specific license qualifies as a free |
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href="/licenses/license-list.html">list of licenses</a>. If the |
software license, see our <a href="/licenses/license-list.html">list |
| 246 |
license you are concerned with is not listed there, you can ask us |
of licenses</a>. If the license you are concerned with is not |
| 247 |
about it by sending us email at <a |
listed there, you can ask us about it by sending us email at |
| 248 |
href="mailto:licensing@gnu.org"><licensing@gnu.org></a>.</p> <p> |
<a href="mailto:licensing@gnu.org"><licensing@gnu.org></a>. |
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</p> |
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<p> |
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If you are contemplating writing a new license, please contact the FSF |
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 |
by writing to that address. The proliferation of different free software |
| 254 |
software licenses means increased work for users in understanding the |
licenses means increased work for users in understanding the licenses; |
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licenses; we may be able to help you find an existing Free Software |
we may be able to help you find an existing Free Software license that |
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license that meets your needs. |
meets your needs. |
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</p> |
</p> |
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<p> |
<p> |
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help you can ensure that the license really is a Free Software license |
help you can ensure that the license really is a Free Software license |
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and avoid various practical problems. |
and avoid various practical problems. |
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</p> |
</p> |
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<hr /> |
<hr /> |
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<p> |
<p> |
| 268 |
Another group has started using the term "open source" to mean |
Another group has started using the term <q>open source</q> to mean |
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something close (but not identical) to "free software". We prefer the |
something close (but not identical) to <q>free software.</q> We prefer |
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term "free software" because, once you have heard it refers to freedom |
the term <q>free software</q> because, once you have heard it refers to |
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rather than price, <a href="free-software-for-freedom.html">it calls |
freedom rather than price, <a href="free-software-for-freedom.html">it |
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to mind freedom</a>. The word "open" never does that.</p> |
calls to mind freedom</a>. The word <q>open</q> never does that. |
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</p> |
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<h4><a href="/philosophy/philosophy.html">Other Texts to Read</a></h4> |
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