xref: /freebsd/contrib/diff/doc/fdl.texi (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1
2@node GNU Free Documentation License
3@appendixsec GNU Free Documentation License
4
5@cindex FDL, GNU Free Documentation License
6@center Version 1.2, November 2002
7
8@display
9Copyright @copyright{} 2000,2001,2002 Free Software Foundation, Inc.
1059 Temple Place, Suite 330, Boston, MA  02111-1307, USA
11
12Everyone is permitted to copy and distribute verbatim copies
13of this license document, but changing it is not allowed.
14@end display
15
16@enumerate 0
17@item
18PREAMBLE
19
20The purpose of this License is to make a manual, textbook, or other
21functional and useful document @dfn{free} in the sense of freedom: to
22assure everyone the effective freedom to copy and redistribute it,
23with or without modifying it, either commercially or noncommercially.
24Secondarily, this License preserves for the author and publisher a way
25to get credit for their work, while not being considered responsible
26for modifications made by others.
27
28This License is a kind of ``copyleft'', which means that derivative
29works of the document must themselves be free in the same sense.  It
30complements the GNU General Public License, which is a copyleft
31license designed for free software.
32
33We have designed this License in order to use it for manuals for free
34software, because free software needs free documentation: a free
35program should come with manuals providing the same freedoms that the
36software does.  But this License is not limited to software manuals;
37it can be used for any textual work, regardless of subject matter or
38whether it is published as a printed book.  We recommend this License
39principally for works whose purpose is instruction or reference.
40
41@item
42APPLICABILITY AND DEFINITIONS
43
44This License applies to any manual or other work, in any medium, that
45contains a notice placed by the copyright holder saying it can be
46distributed under the terms of this License.  Such a notice grants a
47world-wide, royalty-free license, unlimited in duration, to use that
48work under the conditions stated herein.  The ``Document'', below,
49refers to any such manual or work.  Any member of the public is a
50licensee, and is addressed as ``you''.  You accept the license if you
51copy, modify or distribute the work in a way requiring permission
52under copyright law.
53
54A ``Modified Version'' of the Document means any work containing the
55Document or a portion of it, either copied verbatim, or with
56modifications and/or translated into another language.
57
58A ``Secondary Section'' is a named appendix or a front-matter section
59of the Document that deals exclusively with the relationship of the
60publishers or authors of the Document to the Document's overall
61subject (or to related matters) and contains nothing that could fall
62directly within that overall subject.  (Thus, if the Document is in
63part a textbook of mathematics, a Secondary Section may not explain
64any mathematics.)  The relationship could be a matter of historical
65connection with the subject or with related matters, or of legal,
66commercial, philosophical, ethical or political position regarding
67them.
68
69The ``Invariant Sections'' are certain Secondary Sections whose titles
70are designated, as being those of Invariant Sections, in the notice
71that says that the Document is released under this License.  If a
72section does not fit the above definition of Secondary then it is not
73allowed to be designated as Invariant.  The Document may contain zero
74Invariant Sections.  If the Document does not identify any Invariant
75Sections then there are none.
76
77The ``Cover Texts'' are certain short passages of text that are listed,
78as Front-Cover Texts or Back-Cover Texts, in the notice that says that
79the Document is released under this License.  A Front-Cover Text may
80be at most 5 words, and a Back-Cover Text may be at most 25 words.
81
82A ``Transparent'' copy of the Document means a machine-readable copy,
83represented in a format whose specification is available to the
84general public, that is suitable for revising the document
85straightforwardly with generic text editors or (for images composed of
86pixels) generic paint programs or (for drawings) some widely available
87drawing editor, and that is suitable for input to text formatters or
88for automatic translation to a variety of formats suitable for input
89to text formatters.  A copy made in an otherwise Transparent file
90format whose markup, or absence of markup, has been arranged to thwart
91or discourage subsequent modification by readers is not Transparent.
92An image format is not Transparent if used for any substantial amount
93of text.  A copy that is not ``Transparent'' is called ``Opaque''.
94
95Examples of suitable formats for Transparent copies include plain
96@sc{ascii} without markup, Texinfo input format, La@TeX{} input
97format, @acronym{SGML} or @acronym{XML} using a publicly available
98@acronym{DTD}, and standard-conforming simple @acronym{HTML},
99PostScript or @acronym{PDF} designed for human modification.  Examples
100of transparent image formats include @acronym{PNG}, @acronym{XCF} and
101@acronym{JPG}.  Opaque formats include proprietary formats that can be
102read and edited only by proprietary word processors, @acronym{SGML} or
103@acronym{XML} for which the @acronym{DTD} and/or processing tools are
104not generally available, and the machine-generated @acronym{HTML},
105PostScript or @acronym{PDF} produced by some word processors for
106output purposes only.
107
108The ``Title Page'' means, for a printed book, the title page itself,
109plus such following pages as are needed to hold, legibly, the material
110this License requires to appear in the title page.  For works in
111formats which do not have any title page as such, ``Title Page'' means
112the text near the most prominent appearance of the work's title,
113preceding the beginning of the body of the text.
114
115A section ``Entitled XYZ'' means a named subunit of the Document whose
116title either is precisely XYZ or contains XYZ in parentheses following
117text that translates XYZ in another language.  (Here XYZ stands for a
118specific section name mentioned below, such as ``Acknowledgements'',
119``Dedications'', ``Endorsements'', or ``History''.)  To ``Preserve the Title''
120of such a section when you modify the Document means that it remains a
121section ``Entitled XYZ'' according to this definition.
122
123The Document may include Warranty Disclaimers next to the notice which
124states that this License applies to the Document.  These Warranty
125Disclaimers are considered to be included by reference in this
126License, but only as regards disclaiming warranties: any other
127implication that these Warranty Disclaimers may have is void and has
128no effect on the meaning of this License.
129
130@item
131VERBATIM COPYING
132
133You may copy and distribute the Document in any medium, either
134commercially or noncommercially, provided that this License, the
135copyright notices, and the license notice saying this License applies
136to the Document are reproduced in all copies, and that you add no other
137conditions whatsoever to those of this License.  You may not use
138technical measures to obstruct or control the reading or further
139copying of the copies you make or distribute.  However, you may accept
140compensation in exchange for copies.  If you distribute a large enough
141number of copies you must also follow the conditions in section 3.
142
143You may also lend copies, under the same conditions stated above, and
144you may publicly display copies.
145
146@item
147COPYING IN QUANTITY
148
149If you publish printed copies (or copies in media that commonly have
150printed covers) of the Document, numbering more than 100, and the
151Document's license notice requires Cover Texts, you must enclose the
152copies in covers that carry, clearly and legibly, all these Cover
153Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
154the back cover.  Both covers must also clearly and legibly identify
155you as the publisher of these copies.  The front cover must present
156the full title with all words of the title equally prominent and
157visible.  You may add other material on the covers in addition.
158Copying with changes limited to the covers, as long as they preserve
159the title of the Document and satisfy these conditions, can be treated
160as verbatim copying in other respects.
161
162If the required texts for either cover are too voluminous to fit
163legibly, you should put the first ones listed (as many as fit
164reasonably) on the actual cover, and continue the rest onto adjacent
165pages.
166
167If you publish or distribute Opaque copies of the Document numbering
168more than 100, you must either include a machine-readable Transparent
169copy along with each Opaque copy, or state in or with each Opaque copy
170a computer-network location from which the general network-using
171public has access to download using public-standard network protocols
172a complete Transparent copy of the Document, free of added material.
173If you use the latter option, you must take reasonably prudent steps,
174when you begin distribution of Opaque copies in quantity, to ensure
175that this Transparent copy will remain thus accessible at the stated
176location until at least one year after the last time you distribute an
177Opaque copy (directly or through your agents or retailers) of that
178edition to the public.
179
180It is requested, but not required, that you contact the authors of the
181Document well before redistributing any large number of copies, to give
182them a chance to provide you with an updated version of the Document.
183
184@item
185MODIFICATIONS
186
187You may copy and distribute a Modified Version of the Document under
188the conditions of sections 2 and 3 above, provided that you release
189the Modified Version under precisely this License, with the Modified
190Version filling the role of the Document, thus licensing distribution
191and modification of the Modified Version to whoever possesses a copy
192of it.  In addition, you must do these things in the Modified Version:
193
194@enumerate A
195@item
196Use in the Title Page (and on the covers, if any) a title distinct
197from that of the Document, and from those of previous versions
198(which should, if there were any, be listed in the History section
199of the Document).  You may use the same title as a previous version
200if the original publisher of that version gives permission.
201
202@item
203List on the Title Page, as authors, one or more persons or entities
204responsible for authorship of the modifications in the Modified
205Version, together with at least five of the principal authors of the
206Document (all of its principal authors, if it has fewer than five),
207unless they release you from this requirement.
208
209@item
210State on the Title page the name of the publisher of the
211Modified Version, as the publisher.
212
213@item
214Preserve all the copyright notices of the Document.
215
216@item
217Add an appropriate copyright notice for your modifications
218adjacent to the other copyright notices.
219
220@item
221Include, immediately after the copyright notices, a license notice
222giving the public permission to use the Modified Version under the
223terms of this License, in the form shown in the Addendum below.
224
225@item
226Preserve in that license notice the full lists of Invariant Sections
227and required Cover Texts given in the Document's license notice.
228
229@item
230Include an unaltered copy of this License.
231
232@item
233Preserve the section Entitled ``History'', Preserve its Title, and add
234to it an item stating at least the title, year, new authors, and
235publisher of the Modified Version as given on the Title Page.  If
236there is no section Entitled ``History'' in the Document, create one
237stating the title, year, authors, and publisher of the Document as
238given on its Title Page, then add an item describing the Modified
239Version as stated in the previous sentence.
240
241@item
242Preserve the network location, if any, given in the Document for
243public access to a Transparent copy of the Document, and likewise
244the network locations given in the Document for previous versions
245it was based on.  These may be placed in the ``History'' section.
246You may omit a network location for a work that was published at
247least four years before the Document itself, or if the original
248publisher of the version it refers to gives permission.
249
250@item
251For any section Entitled ``Acknowledgements'' or ``Dedications'', Preserve
252the Title of the section, and preserve in the section all the
253substance and tone of each of the contributor acknowledgements and/or
254dedications given therein.
255
256@item
257Preserve all the Invariant Sections of the Document,
258unaltered in their text and in their titles.  Section numbers
259or the equivalent are not considered part of the section titles.
260
261@item
262Delete any section Entitled ``Endorsements''.  Such a section
263may not be included in the Modified Version.
264
265@item
266Do not retitle any existing section to be Entitled ``Endorsements'' or
267to conflict in title with any Invariant Section.
268
269@item
270Preserve any Warranty Disclaimers.
271@end enumerate
272
273If the Modified Version includes new front-matter sections or
274appendices that qualify as Secondary Sections and contain no material
275copied from the Document, you may at your option designate some or all
276of these sections as invariant.  To do this, add their titles to the
277list of Invariant Sections in the Modified Version's license notice.
278These titles must be distinct from any other section titles.
279
280You may add a section Entitled ``Endorsements'', provided it contains
281nothing but endorsements of your Modified Version by various
282parties---for example, statements of peer review or that the text has
283been approved by an organization as the authoritative definition of a
284standard.
285
286You may add a passage of up to five words as a Front-Cover Text, and a
287passage of up to 25 words as a Back-Cover Text, to the end of the list
288of Cover Texts in the Modified Version.  Only one passage of
289Front-Cover Text and one of Back-Cover Text may be added by (or
290through arrangements made by) any one entity.  If the Document already
291includes a cover text for the same cover, previously added by you or
292by arrangement made by the same entity you are acting on behalf of,
293you may not add another; but you may replace the old one, on explicit
294permission from the previous publisher that added the old one.
295
296The author(s) and publisher(s) of the Document do not by this License
297give permission to use their names for publicity for or to assert or
298imply endorsement of any Modified Version.
299
300@item
301COMBINING DOCUMENTS
302
303You may combine the Document with other documents released under this
304License, under the terms defined in section 4 above for modified
305versions, provided that you include in the combination all of the
306Invariant Sections of all of the original documents, unmodified, and
307list them all as Invariant Sections of your combined work in its
308license notice, and that you preserve all their Warranty Disclaimers.
309
310The combined work need only contain one copy of this License, and
311multiple identical Invariant Sections may be replaced with a single
312copy.  If there are multiple Invariant Sections with the same name but
313different contents, make the title of each such section unique by
314adding at the end of it, in parentheses, the name of the original
315author or publisher of that section if known, or else a unique number.
316Make the same adjustment to the section titles in the list of
317Invariant Sections in the license notice of the combined work.
318
319In the combination, you must combine any sections Entitled ``History''
320in the various original documents, forming one section Entitled
321``History''; likewise combine any sections Entitled ``Acknowledgements'',
322and any sections Entitled ``Dedications''.  You must delete all
323sections Entitled ``Endorsements.''
324
325@item
326COLLECTIONS OF DOCUMENTS
327
328You may make a collection consisting of the Document and other documents
329released under this License, and replace the individual copies of this
330License in the various documents with a single copy that is included in
331the collection, provided that you follow the rules of this License for
332verbatim copying of each of the documents in all other respects.
333
334You may extract a single document from such a collection, and distribute
335it individually under this License, provided you insert a copy of this
336License into the extracted document, and follow this License in all
337other respects regarding verbatim copying of that document.
338
339@item
340AGGREGATION WITH INDEPENDENT WORKS
341
342A compilation of the Document or its derivatives with other separate
343and independent documents or works, in or on a volume of a storage or
344distribution medium, is called an ``aggregate'' if the copyright
345resulting from the compilation is not used to limit the legal rights
346of the compilation's users beyond what the individual works permit.
347When the Document is included in an aggregate, this License does not
348apply to the other works in the aggregate which are not themselves
349derivative works of the Document.
350
351If the Cover Text requirement of section 3 is applicable to these
352copies of the Document, then if the Document is less than one half of
353the entire aggregate, the Document's Cover Texts may be placed on
354covers that bracket the Document within the aggregate, or the
355electronic equivalent of covers if the Document is in electronic form.
356Otherwise they must appear on printed covers that bracket the whole
357aggregate.
358
359@item
360TRANSLATION
361
362Translation is considered a kind of modification, so you may
363distribute translations of the Document under the terms of section 4.
364Replacing Invariant Sections with translations requires special
365permission from their copyright holders, but you may include
366translations of some or all Invariant Sections in addition to the
367original versions of these Invariant Sections.  You may include a
368translation of this License, and all the license notices in the
369Document, and any Warranty Disclaimers, provided that you also include
370the original English version of this License and the original versions
371of those notices and disclaimers.  In case of a disagreement between
372the translation and the original version of this License or a notice
373or disclaimer, the original version will prevail.
374
375If a section in the Document is Entitled ``Acknowledgements'',
376``Dedications'', or ``History'', the requirement (section 4) to Preserve
377its Title (section 1) will typically require changing the actual
378title.
379
380@item
381TERMINATION
382
383You may not copy, modify, sublicense, or distribute the Document except
384as expressly provided for under this License.  Any other attempt to
385copy, modify, sublicense or distribute the Document is void, and will
386automatically terminate your rights under this License.  However,
387parties who have received copies, or rights, from you under this
388License will not have their licenses terminated so long as such
389parties remain in full compliance.
390
391@item
392FUTURE REVISIONS OF THIS LICENSE
393
394The Free Software Foundation may publish new, revised versions
395of the GNU Free Documentation License from time to time.  Such new
396versions will be similar in spirit to the present version, but may
397differ in detail to address new problems or concerns.  See
398@uref{http://www.gnu.org/copyleft/}.
399
400Each version of the License is given a distinguishing version number.
401If the Document specifies that a particular numbered version of this
402License ``or any later version'' applies to it, you have the option of
403following the terms and conditions either of that specified version or
404of any later version that has been published (not as a draft) by the
405Free Software Foundation.  If the Document does not specify a version
406number of this License, you may choose any version ever published (not
407as a draft) by the Free Software Foundation.
408@end enumerate
409
410@page
411@appendixsubsec ADDENDUM: How to use this License for your documents
412
413To use this License in a document you have written, include a copy of
414the License in the document and put the following copyright and
415license notices just after the title page:
416
417@smallexample
418@group
419  Copyright (C)  @var{year}  @var{your name}.
420  Permission is granted to copy, distribute and/or modify this document
421  under the terms of the GNU Free Documentation License, Version 1.2
422  or any later version published by the Free Software Foundation;
423  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
424  Texts.  A copy of the license is included in the section entitled ``GNU
425  Free Documentation License''.
426@end group
427@end smallexample
428
429If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
430replace the ``with...Texts.'' line with this:
431
432@smallexample
433@group
434    with the Invariant Sections being @var{list their titles}, with
435    the Front-Cover Texts being @var{list}, and with the Back-Cover Texts
436    being @var{list}.
437@end group
438@end smallexample
439
440If you have Invariant Sections without Cover Texts, or some other
441combination of the three, merge those two alternatives to suit the
442situation.
443
444If your document contains nontrivial examples of program code, we
445recommend releasing these examples in parallel under your choice of
446free software license, such as the GNU General Public License,
447to permit their use in free software.
448
449@c Local Variables:
450@c ispell-local-pdict: "ispell-dict"
451@c End:
452
453