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1  <!--#include virtual="/server/header.html" -->  <!--#include virtual="/server/header.html" -->
2  <!-- Parent-Version: 1.75 -->  <!-- Parent-Version: 1.79 -->
3  <title>What is free software?  <title>What is free software?
4  - GNU Project - Free Software Foundation</title>  - GNU Project - Free Software Foundation</title>
5    
# Line 11  Line 11 
11    
12  <h2>What is free software?</h2>  <h2>What is free software?</h2>
13    
14    <blockquote class="note" id="fsf-licensing"><p style="font-size: 80%">
15    Have a question about free software licensing not answered here?
16    See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
17    and if necessary contact the FSF Compliance Lab
18    at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
19    </blockquote>
20    
21  <h3>The Free Software Definition</h3>  <h3>The Free Software Definition</h3>
22    
23    <!--#include virtual="/licenses/fsf-licensing.html" -->
24  <blockquote>  <blockquote>
25  <p>  <p>
26  The free software definition presents the criteria for whether a  The free software definition presents the criteria for whether a
# Line 26  software. Line 34  software.
34    
35  <p>  <p>
36  &ldquo;Free software&rdquo; means software that respects users'  &ldquo;Free software&rdquo; means software that respects users'
37  freedom and community.  Roughly, <b>the users have the freedom to run,  freedom and community.  Roughly, it means that <b>the users have the
38  copy, distribute, study, change and improve the software</b>.  freedom to run, copy, distribute, study, change and improve the
39    software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
40    liberty, not price.  To understand the concept, you should think of
41    &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
42    &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
43    software,&rdquo; borrowing the French or Spanish word for
44    &ldquo;free&rdquo; as in freedom, to show we do not mean the software
45    is gratis.
46  </p>  </p>
47    
48  <p>  <p>
49  Thus, &ldquo;free software&rdquo; is a matter of liberty, not price.  We campaign for these freedoms because everyone deserves them.  With
50  To understand the concept, you should think of &ldquo;free&rdquo; as  these freedoms, the users (both individually and collectively) control
51  in &ldquo;free speech,&rdquo; not as in &ldquo;free beer&rdquo;.  the program and what it does for them.  When users don't control the
52    program, we call it a &ldquo;nonfree&rdquo; or
53    &ldquo;proprietary&rdquo; program.  The nonfree program controls the
54    users, and the developer controls the program; this makes the
55    program <a href="/philosophy/free-software-even-more-important.html">
56    an instrument of unjust power</a>.
57  </p>  </p>
58    
59  <p>  <h4> The four essential freedoms</h4>
 With these freedoms, the users (both individually and collectively)  
 control the program and what it does for them.  When users don't  
 control the program, the program controls the users.  The developer  
 controls the program, and through it exercises power over the users.  
 Therefore, a &ldquo;nonfree&rdquo; or &ldquo;proprietary&rdquo; program  
 is <a href="/philosophy/free-software-even-more-important.html"> an  
 instrument of unjust power</a>.  
 </p>  
60    
61  <p>  <p>
62  A program is free software if the program's users have the  A program is free software if the program's users have the
# Line 52  four essential freedoms: Line 64  four essential freedoms:
64  </p>  </p>
65    
66  <ul>  <ul>
67    <li>The freedom to run the program, for any purpose (freedom 0).</li>    <li>The freedom to run the program as you wish,
68          for any purpose (freedom 0).</li>
69    <li>The freedom to study how the program works, and change it so it    <li>The freedom to study how the program works, and change it so it
70        does your computing as you wish (freedom 1). Access to the source        does your computing as you wish (freedom 1). Access to the source
71        code is a precondition for this.        code is a precondition for this.
# Line 73  freedoms.  Otherwise, it is nonfree.  Wh Line 86  freedoms.  Otherwise, it is nonfree.  Wh
86  nonfree distribution schemes in terms of how far they fall short of  nonfree distribution schemes in terms of how far they fall short of
87  being free, we consider them all equally unethical.</p>  being free, we consider them all equally unethical.</p>
88    
89  <p>The rest of this page clarifies certain points about what makes  <p>In any given scenario, these freedoms must apply to whatever code
90  specific freedoms adequate or not.</p>  we plan to make use of, or lead others to make use of.  For instance,
91    consider a program A which automatically launches a program B to
92  <p>Freedom to distribute (freedoms 2 and 3) means you are free to  handle some cases.  If we plan to distribute A as it stands, that
93  redistribute copies, either with or without modifications, either  implies users will need B, so we need to judge whether both A and B
94  gratis or charging a fee for distribution, to  are free.  However, if we plan to modify A so that it doesn't use B,
95  <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these  only A needs to be free; B is not pertinent to that plan.</p>
 things means (among other things) that you do not have to ask or pay  
 for permission to do so.  
 </p>  
96    
97  <p>  <p>
98  You should also have the freedom to make modifications and use them  &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free
99  privately in your own work or play, without even mentioning that they  program must be available for commercial use, commercial development,
100  exist.  If you do publish your changes, you should not be required to  and commercial distribution.  Commercial development of free software
101  notify anyone in particular, or in any particular way.  is no longer unusual; such free commercial software is very important.
102    You may have paid money to get copies of free software, or you may have
103    obtained copies at no charge.  But regardless of how you got your copies,
104    you always have the freedom to copy and change the software, even to
105    <a href="/philosophy/selling.html">sell copies</a>.
106  </p>  </p>
107    
108    <p>The rest of this page clarifies certain points about what makes
109    specific freedoms adequate or not.</p>
110    
111    <h4>The freedom to run the program as you wish</h4>
112    
113  <p>  <p>
114  The freedom to run the program means the freedom for any kind of person  The freedom to run the program means the freedom for any kind of person
115  or organization to use it on any kind of computer system, for any kind of  or organization to use it on any kind of computer system, for any kind of
# Line 103  for her purposes, but you are not entitl Line 122  for her purposes, but you are not entitl
122  </p>  </p>
123    
124  <p>  <p>
125  The freedom to redistribute copies must include binary or executable  The freedom to run the program as you wish means that you are not
126  forms of the program, as well as source code, for both modified and  forbidden or stopped from doing so.  It has nothing to do with what
127  unmodified versions.  (Distributing programs in runnable form is necessary  functionality the program has, or whether it is useful for what you
128  for conveniently installable free operating systems.)  It is OK if there  want to do.</p>
129  is no way to produce a binary or executable form for a certain program  
130  (since some languages don't support that feature), but you must have the  <h4>The freedom to study the source code and make changes</h4>
 freedom to redistribute such forms should you find or develop a way to  
 make them.  
 </p>  
131    
132  <p>  <p>
133  In order for freedoms 1 and 3 (the freedom to make changes and the  In order for freedoms 1 and 3 (the freedom to make changes and the
# Line 128  the original.  If the program is deliver Line 144  the original.  If the program is deliver
144  run someone else's modified versions but refuse to run yours &mdash; a  run someone else's modified versions but refuse to run yours &mdash; a
145  practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,  practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
146  or (in its practitioners' perverse terminology) as &ldquo;secure  or (in its practitioners' perverse terminology) as &ldquo;secure
147  boot&rdquo; &mdash; freedom 1 becomes a theoretical fiction rather  boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
148  than a practical freedom.  This is not sufficient.  In other words,  practical reality.  These binaries are not free
149  these binaries are not free software even if the source code they are  software even if the source code they are compiled from is free.
 compiled from is free.  
150  </p>  </p>
151    
152  <p>  <p>
# Line 143  license is too restrictive to qualify as Line 158  license is too restrictive to qualify as
158  </p>  </p>
159    
160  <p>  <p>
161    Whether a change constitutes an improvement is a subjective matter.
162    If your right to modify a program is limited, in substance, to changes that
163    someone else considers an improvement, that program is not free.
164    </p>
165    
166    <h4>The freedom to redistribute if you wish: basic requirements</h4>
167    
168    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
169    redistribute copies, either with or without modifications, either
170    gratis or charging a fee for distribution, to
171    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
172    things means (among other things) that you do not have to ask or pay
173    for permission to do so.
174    </p>
175    
176    <p>
177    You should also have the freedom to make modifications and use them
178    privately in your own work or play, without even mentioning that they
179    exist.  If you do publish your changes, you should not be required to
180    notify anyone in particular, or in any particular way.
181    </p>
182    
183    <p>
184  Freedom 3 includes the freedom to release your modified versions  Freedom 3 includes the freedom to release your modified versions
185  as free software.  A free license may also permit other ways of  as free software.  A free license may also permit other ways of
186  releasing them; in other words, it does not have to be  releasing them; in other words, it does not have to be
# Line 152  as a free license. Line 190  as a free license.
190  </p>  </p>
191    
192  <p>  <p>
193  In order for these freedoms to be real, they must be permanent and  The freedom to redistribute copies must include binary or executable
194  irrevocable as long as you do nothing wrong; if the developer of the  forms of the program, as well as source code, for both modified and
195  software has the power to revoke the license, or retroactively add  unmodified versions.  (Distributing programs in runnable form is necessary
196  restrictions to its terms, without your doing anything wrong to give  for conveniently installable free operating systems.)  It is OK if there
197  cause, the software is not free.  is no way to produce a binary or executable form for a certain program
198    (since some languages don't support that feature), but you must have the
199    freedom to redistribute such forms should you find or develop a way to
200    make them.
201  </p>  </p>
202    
203    <h4>Copyleft</h4>
204    
205  <p>  <p>
206  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
207  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
208  freedoms.  For example, copyleft (very simply stated) is the rule that  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>
209  when redistributing the program, you cannot add restrictions to deny  (very simply stated) is the rule that when redistributing the program,
210  other people the central freedoms.  This rule does not conflict with  you cannot add restrictions to deny other people the central freedoms.
211  the central freedoms; rather it protects them.  This rule does not conflict with the central freedoms; rather it
212    protects them.
213  </p>  </p>
214    
215  <p>  <p>
216  &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free  In the GNU project, we use copyleft to protect the four freedoms
217  program must be available for commercial use, commercial development,  legally for everyone.  We believe there are important reasons why
218  and commercial distribution.  Commercial development of free software  <a href="/philosophy/pragmatic.html">it is better to use
219  is no longer unusual; such free commercial software is very important.  copyleft</a>.  However,
220  You may have paid money to get copies of free software, or you may have  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
221  obtained copies at no charge.  But regardless of how you got your copies,  noncopylefted free software</a> is ethical
222  you always have the freedom to copy and change the software, even to  too.  See <a href="/philosophy/categories.html">Categories of Free
223  <a href="/philosophy/selling.html">sell copies</a>.  Software</a> for a description of how &ldquo;free software,&rdquo;
224    &ldquo;copylefted software&rdquo; and other categories of software
225    relate to each other.
226  </p>  </p>
227    
228  <p>  <h4>Rules about packaging and distribution details</h4>
 Whether a change constitutes an improvement is a subjective matter.  
 If your right to modify a program is limited, in substance, to changes that  
 someone else considers an improvement, that program is not free.  
 </p>  
229    
230  <p>  <p>
231  However, rules about how to package a modified version are acceptable,  Rules about how to package a modified version are acceptable,
232  if they don't substantively limit your freedom to release modified  if they don't substantively limit your freedom to release modified
233  versions, or your freedom to make and use modified versions privately.  versions, or your freedom to make and use modified versions privately.
234  Thus, it is acceptable for the license to require that you change the  Thus, it is acceptable for the license to require that you change the
# Line 218  sort of requirement is acceptable only i Line 260  sort of requirement is acceptable only i
260  facility that allows you to specify the original program's name as an  facility that allows you to specify the original program's name as an
261  alias for the modified version.</p>  alias for the modified version.</p>
262    
263  <p>  <h4>Export regulations</h4>
 In the GNU project, we use  
 <a href="/copyleft/copyleft.html">copyleft</a>  
 to protect these freedoms legally for everyone.  But  
 <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">noncopylefted  
 free software</a> also exists.  We believe there are important reasons why  
 <a href="/philosophy/pragmatic.html">it is better to use copyleft</a>,  
 but if your program is noncopylefted free software, it is still basically  
 ethical. (See <a href="/philosophy/categories.html">Categories of Free Software</a> for a description of how &ldquo;free software,&rdquo; &ldquo;copylefted software&rdquo; and other categories of software relate to each other.)  
 </p>  
264    
265  <p>  <p>
266  Sometimes government <a id="exportcontrol">export control regulations</a>  Sometimes government <a id="exportcontrol">export control regulations</a>
# Line 251  export law could make the requirement no Line 284  export law could make the requirement no
284  software nonfree.  software nonfree.
285  </p>  </p>
286    
287    <h4>Legal considerations</h4>
288    
289    <p>
290    In order for these freedoms to be real, they must be permanent and
291    irrevocable as long as you do nothing wrong; if the developer of the
292    software has the power to revoke the license, or retroactively add
293    restrictions to its terms, without your doing anything wrong to give
294    cause, the software is not free.
295    </p>
296    
297    <p>
298    A free license may not require compliance with the license of a
299    nonfree program.  Thus, for instance, if a license requires you to
300    comply with the licenses of &ldquo;all the programs you use&rdquo;, in
301    the case of a user that runs nonfree programs this would require
302    compliance with the licenses of those nonfree programs; that makes the
303    license nonfree.
304    </p>
305    
306    <p>
307    It is acceptable for a free license to specify which jurisdiction's
308    law applies, or where litigation must be done, or both.
309    </p>
310    
311    <h4>Contract-based licenses</h4>
312    
313  <p>  <p>
314  Most free software licenses are based on copyright, and there are limits  Most free software licenses are based on copyright, and there are limits
315  on what kinds of requirements can be imposed through copyright.  If a  on what kinds of requirements can be imposed through copyright.  If a
# Line 270  legitimate, we will have to think about Line 329  legitimate, we will have to think about
329  it is nonfree.  it is nonfree.
330  </p>  </p>
331    
332    <h4>Use the right words when talking about free software</h4>
333    
334  <p>  <p>
335  When talking about free software, it is best to avoid using terms  When talking about free software, it is best to avoid using terms
336  like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that  like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
# Line 281  a list of proper <a href="/philosophy/fs Line 342  a list of proper <a href="/philosophy/fs
342  &ldquo;free software&rdquo;</a> into various languages.  &ldquo;free software&rdquo;</a> into various languages.
343  </p>  </p>
344    
345    <h4>How we interpret these criteria</h4>
346    
347  <p>  <p>
348  Finally, note that criteria such as those stated in this free software  Finally, note that criteria such as those stated in this free software
349  definition require careful thought for their interpretation.  To decide  definition require careful thought for their interpretation.  To decide
# Line 295  a conclusion about a new issue, we often Line 358  a conclusion about a new issue, we often
358  it easier to see why certain licenses do or don't qualify.  it easier to see why certain licenses do or don't qualify.
359  </p>  </p>
360    
361    <h4>Get help with free licenses</h4>
362    
363  <p>  <p>
364  If you are interested in whether a specific license qualifies as a free  If you are interested in whether a specific license qualifies as a free
365  software license, see our <a href="/licenses/license-list.html">list  software license, see our <a href="/licenses/license-list.html">list
# Line 342  free cultural works</a> applicable to an Line 407  free cultural works</a> applicable to an
407  <h3 id="open-source">Open Source?</h3>  <h3 id="open-source">Open Source?</h3>
408    
409  <p>  <p>
410  Another group has started using the term &ldquo;open source&rdquo; to mean  Another group uses the term &ldquo;open source&rdquo; to mean
411  something close (but not identical) to &ldquo;free software&rdquo;.  We  something close (but not identical) to &ldquo;free software&rdquo;.  We
412  prefer the term &ldquo;free software&rdquo; because, once you have heard that  prefer the term &ldquo;free software&rdquo; because, once you have heard that
413  it refers to freedom rather than price, it calls to mind freedom.  The  it refers to freedom rather than price, it calls to mind freedom.  The
# Line 358  was changed.</p> Line 423  was changed.</p>
423    
424  <ul>  <ul>
425    
426    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.140&amp;r2=1.141">Version
427    1.141</a>: Clarify which code needs to be free.</li>
428    
429    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.134&amp;r2=1.135">Version
430    1.135</a>: Say each time that freedom 0 is the freedom to run the program
431    as you wish.</li>
432    
433    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.133&amp;r2=1.134">Version
434    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
435    
436    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.130&amp;r2=1.131">Version
437    1.131</a>: A free license may not require compliance with a nonfree license
438    of another program.</li>
439    
440    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.128&amp;r2=1.129">Version
441    1.129</a>: State explicitly that choice of law and choice of forum
442    specifications are allowed.  (This was always our policy.)</li>
443    
444  <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.121&amp;r2=1.122">Version  <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.121&amp;r2=1.122">Version
445  1.122</a>: An export control requirement is a real problem if the  1.122</a>: An export control requirement is a real problem if the
446  requirement is nontrivial; otherwise it is only a potential problem.</li>  requirement is nontrivial; otherwise it is only a potential problem.</li>
# Line 446  licenses.</li> Line 529  licenses.</li>
529    
530  <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.10&amp;r2=1.11">Version  <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.10&amp;r2=1.11">Version
531  1.11</a>: Note that a free license may require you to send a copy of  1.11</a>: Note that a free license may require you to send a copy of
532  versions you distribute to the author.</li>  versions you distribute to previous developers on request.</li>
533    
534  </ul>  </ul>
535    
# Line 462  interface</a>.</p> Line 545  interface</a>.</p>
545  </div><!-- for id="content", starts in the include above -->  </div><!-- for id="content", starts in the include above -->
546  <!--#include virtual="/server/footer.html" -->  <!--#include virtual="/server/footer.html" -->
547  <div id="footer">  <div id="footer">
548    <div class="unprintable">
549    
550  <p>Please send general FSF &amp; GNU inquiries to  <p>Please send general FSF &amp; GNU inquiries to
551  <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.  <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
# Line 486  Please see the <a Line 570  Please see the <a
570  href="/server/standards/README.translations.html">Translations  href="/server/standards/README.translations.html">Translations
571  README</a> for information on coordinating and submitting translations  README</a> for information on coordinating and submitting translations
572  of this article.</p>  of this article.</p>
573    </div>
574    
575  <!-- Regarding copyright, in general, standalone pages (as opposed to  <!-- Regarding copyright, in general, standalone pages (as opposed to
576       files generated as part of manuals) on the GNU web server should       files generated as part of manuals) on the GNU web server should
577       be under CC BY-ND 3.0 US.  Please do NOT change or remove this       be under CC BY-ND 4.0.  Please do NOT change or remove this
578       without talking with the webmasters or licensing team first.       without talking with the webmasters or licensing team first.
579       Please make sure the copyright date is consistent with the       Please make sure the copyright date is consistent with the
580       document.  For web pages, it is ok to list just the latest year the       document.  For web pages, it is ok to list just the latest year the
# Line 504  of this article.</p> Line 589  of this article.</p>
589       There is more detail about copyright years in the GNU Maintainers       There is more detail about copyright years in the GNU Maintainers
590       Information document, www.gnu.org/prep/maintain. -->       Information document, www.gnu.org/prep/maintain. -->
591    
592  <p>Copyright &copy; 1996-2002, 2004-2007, 2009, 2010, 2012, 2013  <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2016
593  Free Software Foundation, Inc.</p>  Free Software Foundation, Inc.</p>
594    
595  <p>This page is licensed under a <a rel="license"  <p>This page is licensed under a <a rel="license"
596  href="http://creativecommons.org/licenses/by-nd/3.0/us/">Creative  href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
597  Commons Attribution-NoDerivs 3.0 United States License</a>.</p>  Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
598    
599  <!--#include virtual="/server/bottom-notes.html" -->  <!--#include virtual="/server/bottom-notes.html" -->
600    
601  <p>Updated:  <p class="unprintable">Updated:
602  <!-- timestamp start -->  <!-- timestamp start -->
603  $Date$  $Date$
604  <!-- timestamp end -->  <!-- timestamp end -->

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