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1  <!--#include virtual="/server/header.html" -->  <!--#include virtual="/server/header.html" -->
2  <!-- Parent-Version: 1.77 -->  <!-- 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 10  Line 10 
10  <!--#include virtual="/server/banner.html" -->  <!--#include virtual="/server/banner.html" -->
11    
12  <h2>What is free software?</h2>  <h2>What is free software?</h2>
13  <!--#include virtual="/licenses/fsf-licensing.html" -->  
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    
# Line 33  software</b>.  Thus, &ldquo;free softwar Line 39  software</b>.  Thus, &ldquo;free softwar
39  liberty, not price.  To understand the concept, you should think of  liberty, not price.  To understand the concept, you should think of
40  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
41  &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre  &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
42  software&rdquo; to show we do not mean it is gratis.  software,&rdquo; borrowing the French or Spanish word for
43    &ldquo;free&rdquo; as in freedom, to show we do not mean the software
44    is gratis.
45  </p>  </p>
46    
47  <p>  <p>
# Line 47  program <a href="/philosophy/free-softwa Line 55  program <a href="/philosophy/free-softwa
55  an instrument of unjust power</a>.  an instrument of unjust power</a>.
56  </p>  </p>
57    
58    <h4> The four essential freedoms</h4>
59    
60  <p>  <p>
61  A program is free software if the program's users have the  A program is free software if the program's users have the
62  four essential freedoms:  four essential freedoms:
# Line 81  consider a program A which automatically Line 91  consider a program A which automatically
91  handle some cases.  If we plan to distribute A as it stands, that  handle some cases.  If we plan to distribute A as it stands, that
92  implies users will need B, so we need to judge whether both A and B  implies users will need B, so we need to judge whether both A and B
93  are free.  However, if we plan to modify A so that it doesn't use B,  are free.  However, if we plan to modify A so that it doesn't use B,
94  only A needs to be free; we can ignore B.</p>  only A needs to be free; B is not pertinent to that plan.</p>
95    
96    <p>
97    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free
98    program must be available for commercial use, commercial development,
99    and commercial distribution.  Commercial development of free software
100    is no longer unusual; such free commercial software is very important.
101    You may have paid money to get copies of free software, or you may have
102    obtained copies at no charge.  But regardless of how you got your copies,
103    you always have the freedom to copy and change the software, even to
104    <a href="/philosophy/selling.html">sell copies</a>.
105    </p>
106    
107  <p>The rest of this page clarifies certain points about what makes  <p>The rest of this page clarifies certain points about what makes
108  specific freedoms adequate or not.</p>  specific freedoms adequate or not.</p>
109    
110  <p>Freedom to distribute (freedoms 2 and 3) means you are free to  <h4>The freedom to run the program as you wish</h4>
 redistribute copies, either with or without modifications, either  
 gratis or charging a fee for distribution, to  
 <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these  
 things means (among other things) that you do not have to ask or pay  
 for permission to do so.  
 </p>  
   
 <p>  
 You should also have the freedom to make modifications and use them  
 privately in your own work or play, without even mentioning that they  
 exist.  If you do publish your changes, you should not be required to  
 notify anyone in particular, or in any particular way.  
 </p>  
111    
112  <p>  <p>
113  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
# Line 118  forbidden or stopped from doing so.  It Line 126  forbidden or stopped from doing so.  It
126  functionality the program has, or whether it is useful for what you  functionality the program has, or whether it is useful for what you
127  want to do.</p>  want to do.</p>
128    
129  <p>  <h4>The freedom to study the source code and make changes</h4>
 The freedom to redistribute copies must include binary or executable  
 forms of the program, as well as source code, for both modified and  
 unmodified versions.  (Distributing programs in runnable form is necessary  
 for conveniently installable free operating systems.)  It is OK if there  
 is no way to produce a binary or executable form for a certain program  
 (since some languages don't support that feature), but you must have the  
 freedom to redistribute such forms should you find or develop a way to  
 make them.  
 </p>  
130    
131  <p>  <p>
132  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 158  license is too restrictive to qualify as Line 157  license is too restrictive to qualify as
157  </p>  </p>
158    
159  <p>  <p>
160    Whether a change constitutes an improvement is a subjective matter.
161    If your right to modify a program is limited, in substance, to changes that
162    someone else considers an improvement, that program is not free.
163    </p>
164    
165    <h4>The freedom to redistribute if you wish: basic requirements</h4>
166    
167    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
168    redistribute copies, either with or without modifications, either
169    gratis or charging a fee for distribution, to
170    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
171    things means (among other things) that you do not have to ask or pay
172    for permission to do so.
173    </p>
174    
175    <p>
176    You should also have the freedom to make modifications and use them
177    privately in your own work or play, without even mentioning that they
178    exist.  If you do publish your changes, you should not be required to
179    notify anyone in particular, or in any particular way.
180    </p>
181    
182    <p>
183  Freedom 3 includes the freedom to release your modified versions  Freedom 3 includes the freedom to release your modified versions
184  as free software.  A free license may also permit other ways of  as free software.  A free license may also permit other ways of
185  releasing them; in other words, it does not have to be  releasing them; in other words, it does not have to be
# Line 167  as a free license. Line 189  as a free license.
189  </p>  </p>
190    
191  <p>  <p>
192  In order for these freedoms to be real, they must be permanent and  The freedom to redistribute copies must include binary or executable
193  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
194  software has the power to revoke the license, or retroactively add  unmodified versions.  (Distributing programs in runnable form is necessary
195  restrictions to its terms, without your doing anything wrong to give  for conveniently installable free operating systems.)  It is OK if there
196  cause, the software is not free.  is no way to produce a binary or executable form for a certain program
197    (since some languages don't support that feature), but you must have the
198    freedom to redistribute such forms should you find or develop a way to
199    make them.
200  </p>  </p>
201    
202    <h4>Copyleft</h4>
203    
204  <p>  <p>
205  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
206  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
207  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>
208  (very simply stated) is the rule that when redistributing the program,  (very simply stated) is the rule that when redistributing the program,
# Line 197  Software</a> for a description of how &l Line 224  Software</a> for a description of how &l
224  relate to each other.  relate to each other.
225  </p>  </p>
226    
227  <p>  <h4>Rules about packaging and distribution details</h4>
 &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free  
 program must be available for commercial use, commercial development,  
 and commercial distribution.  Commercial development of free software  
 is no longer unusual; such free commercial software is very important.  
 You may have paid money to get copies of free software, or you may have  
 obtained copies at no charge.  But regardless of how you got your copies,  
 you always have the freedom to copy and change the software, even to  
 <a href="/philosophy/selling.html">sell copies</a>.  
 </p>  
   
 <p>  
 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>  
228    
229  <p>  <p>
230  However, rules about how to package a modified version are acceptable,  Rules about how to package a modified version are acceptable,
231  if they don't substantively limit your freedom to release modified  if they don't substantively limit your freedom to release modified
232  versions, or your freedom to make and use modified versions privately.  versions, or your freedom to make and use modified versions privately.
233  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 247  sort of requirement is acceptable only i Line 259  sort of requirement is acceptable only i
259  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
260  alias for the modified version.</p>  alias for the modified version.</p>
261    
262    <h4>Export regulations</h4>
263    
264  <p>  <p>
265  Sometimes government <a id="exportcontrol">export control regulations</a>  Sometimes government <a id="exportcontrol">export control regulations</a>
266  and trade sanctions can constrain your freedom to distribute copies of  and trade sanctions can constrain your freedom to distribute copies of
# Line 269  export law could make the requirement no Line 283  export law could make the requirement no
283  software nonfree.  software nonfree.
284  </p>  </p>
285    
286    <h4>Legal considerations</h4>
287    
288    <p>
289    In order for these freedoms to be real, they must be permanent and
290    irrevocable as long as you do nothing wrong; if the developer of the
291    software has the power to revoke the license, or retroactively add
292    restrictions to its terms, without your doing anything wrong to give
293    cause, the software is not free.
294    </p>
295    
296  <p>  <p>
297  A free license may not require compliance with the license of a  A free license may not require compliance with the license of a
298  nonfree program.  Thus, for instance, if a license requires you to  nonfree program.  Thus, for instance, if a license requires you to
# Line 283  It is acceptable for a free license to s Line 307  It is acceptable for a free license to s
307  law applies, or where litigation must be done, or both.  law applies, or where litigation must be done, or both.
308  </p>  </p>
309    
310    <h4>Contract-based licenses</h4>
311    
312  <p>  <p>
313  Most free software licenses are based on copyright, and there are limits  Most free software licenses are based on copyright, and there are limits
314  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 302  legitimate, we will have to think about Line 328  legitimate, we will have to think about
328  it is nonfree.  it is nonfree.
329  </p>  </p>
330    
331    <h4>Use the right words when talking about free software</h4>
332    
333  <p>  <p>
334  When talking about free software, it is best to avoid using terms  When talking about free software, it is best to avoid using terms
335  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 313  a list of proper <a href="/philosophy/fs Line 341  a list of proper <a href="/philosophy/fs
341  &ldquo;free software&rdquo;</a> into various languages.  &ldquo;free software&rdquo;</a> into various languages.
342  </p>  </p>
343    
344    <h4>How we interpret these criteria</h4>
345    
346  <p>  <p>
347  Finally, note that criteria such as those stated in this free software  Finally, note that criteria such as those stated in this free software
348  definition require careful thought for their interpretation.  To decide  definition require careful thought for their interpretation.  To decide
# Line 327  a conclusion about a new issue, we often Line 357  a conclusion about a new issue, we often
357  it easier to see why certain licenses do or don't qualify.  it easier to see why certain licenses do or don't qualify.
358  </p>  </p>
359    
360    <h4>Get help with free licenses</h4>
361    
362  <p>  <p>
363  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
364  software license, see our <a href="/licenses/license-list.html">list  software license, see our <a href="/licenses/license-list.html">list
# Line 374  free cultural works</a> applicable to an Line 406  free cultural works</a> applicable to an
406  <h3 id="open-source">Open Source?</h3>  <h3 id="open-source">Open Source?</h3>
407    
408  <p>  <p>
409  Another group has started using the term &ldquo;open source&rdquo; to mean  Another group uses the term &ldquo;open source&rdquo; to mean
410  something close (but not identical) to &ldquo;free software&rdquo;.  We  something close (but not identical) to &ldquo;free software&rdquo;.  We
411  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
412  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 496  licenses.</li> Line 528  licenses.</li>
528    
529  <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
530  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
531  versions you distribute to the author.</li>  versions you distribute to previous developers on request.</li>
532    
533  </ul>  </ul>
534    
# Line 556  of this article.</p> Line 588  of this article.</p>
588       There is more detail about copyright years in the GNU Maintainers       There is more detail about copyright years in the GNU Maintainers
589       Information document, www.gnu.org/prep/maintain. -->       Information document, www.gnu.org/prep/maintain. -->
590    
591  <p>Copyright &copy; 1996-2002, 2004-2007, 2009, 2010, 2012, 2013, 2015  <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2016
592  Free Software Foundation, Inc.</p>  Free Software Foundation, Inc.</p>
593    
594  <p>This page is licensed under a <a rel="license"  <p>This page is licensed under a <a rel="license"

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