1 This is gzip.info, produced by makeinfo version 6.5 from gzip.texi.
3 This manual is for GNU Gzip (version 1.10, 7 August 2018), and documents
4 commands for compressing and decompressing data.
6 Copyright © 1998-1999, 2001-2002, 2006-2007, 2009-2018 Free Software
9 Copyright © 1992, 1993 Jean-loup Gailly
11 Permission is granted to copy, distribute and/or modify this
12 document under the terms of the GNU Free Documentation License,
13 Version 1.3 or any later version published by the Free Software
14 Foundation; with no Invariant Sections, with no Front-Cover Texts,
15 and with no Back-Cover Texts. A copy of the license is included in
16 the section entitled “GNU Free Documentation License”.
17 INFO-DIR-SECTION Compression
19 * Gzip: (gzip). General (de)compression of files (lzw).
22 INFO-DIR-SECTION Individual utilities
24 * gunzip: (gzip)Overview. Decompression.
25 * gzexe: (gzip)Overview. Compress executables.
26 * zcat: (gzip)Overview. Decompression to stdout.
27 * zdiff: (gzip)Overview. Compare compressed files.
28 * zforce: (gzip)Overview. Force .gz extension on files.
29 * zgrep: (gzip)Overview. Search compressed files.
30 * zmore: (gzip)Overview. Decompression output by pages.
34 File: gzip.info, Node: Top, Next: Overview, Up: (dir)
36 GNU Gzip: General file (de)compression
37 **************************************
39 This manual is for GNU Gzip (version 1.10, 7 August 2018), and documents
40 commands for compressing and decompressing data.
42 Copyright © 1998-1999, 2001-2002, 2006-2007, 2009-2018 Free Software
45 Copyright © 1992, 1993 Jean-loup Gailly
47 Permission is granted to copy, distribute and/or modify this
48 document under the terms of the GNU Free Documentation License,
49 Version 1.3 or any later version published by the Free Software
50 Foundation; with no Invariant Sections, with no Front-Cover Texts,
51 and with no Back-Cover Texts. A copy of the license is included in
52 the section entitled “GNU Free Documentation License”.
56 * Overview:: Preliminary information.
57 * Sample:: Sample output from ‘gzip’.
58 * Invoking gzip:: How to run ‘gzip’.
59 * Advanced usage:: Concatenated files.
60 * Environment:: The ‘GZIP’ environment variable
61 * Tapes:: Using ‘gzip’ on tapes.
62 * Problems:: Reporting bugs.
63 * GNU Free Documentation License:: Copying and sharing this manual.
64 * Concept index:: Index of concepts.
67 File: gzip.info, Node: Overview, Next: Sample, Prev: Top, Up: Top
72 ‘gzip’ reduces the size of the named files using Lempel–Ziv coding
73 (LZ77). Whenever possible, each file is replaced by one with the
74 extension ‘.gz’, while keeping the same ownership modes, access and
75 modification times. (The default extension is ‘z’ for MSDOS, OS/2 FAT
76 and Atari.) If no files are specified or if a file name is ‘-’, the
77 standard input is compressed to the standard output. ‘gzip’ will only
78 attempt to compress regular files. In particular, it will ignore
81 If the new file name is too long for its file system, ‘gzip’
82 truncates it. ‘gzip’ attempts to truncate only the parts of the file
83 name longer than 3 characters. (A part is delimited by dots.) If the
84 name consists of small parts only, the longest parts are truncated. For
85 example, if file names are limited to 14 characters, gzip.msdos.exe is
86 compressed to gzi.msd.exe.gz. Names are not truncated on systems which
87 do not have a limit on file name length.
89 By default, ‘gzip’ keeps the original file name in the compressed
90 file. This can be useful when decompressing the file with ‘-N’ if the
91 compressed file name was truncated after a file transfer.
93 If the original is a regular file, ‘gzip’ by default keeps its
94 timestamp in the compressed file. This can be useful when decompressing
95 the file with ‘-N’ if the timestamp was not preserved after a file
96 transfer. However, due to limitations in the current ‘gzip’ file
97 format, fractional seconds are discarded. Also, timestamps must fall
98 within the range 1970-01-01 00:00:01 through 2106-02-07 06:28:15 UTC,
99 and hosts whose operating systems use 32-bit timestamps are further
100 restricted to timestamps no later than 2038-01-19 03:14:07 UTC. The
101 upper bounds assume the typical case where leap seconds are ignored.
103 Compressed files can be restored to their original form using ‘gzip
104 -d’ or ‘gunzip’ or ‘zcat’. If the original name saved in the compressed
105 file is not suitable for its file system, a new name is constructed from
106 the original one to make it legal.
108 ‘gunzip’ takes a list of files on its command line and replaces each
109 file whose name ends with ‘.gz’, ‘.z’ ‘-gz’, ‘-z’, or ‘_z’ (ignoring
110 case) and which begins with the correct magic number with an
111 uncompressed file without the original extension. ‘gunzip’ also
112 recognizes the special extensions ‘.tgz’ and ‘.taz’ as shorthands for
113 ‘.tar.gz’ and ‘.tar.Z’ respectively. When compressing, ‘gzip’ uses the
114 ‘.tgz’ extension if necessary instead of truncating a file with a ‘.tar’
117 ‘gunzip’ can currently decompress files created by ‘gzip’, ‘zip’,
118 ‘compress’ or ‘pack’. The detection of the input format is automatic.
119 When using the first two formats, ‘gunzip’ checks a 32 bit CRC (cyclic
120 redundancy check). For ‘pack’, ‘gunzip’ checks the uncompressed length.
121 The ‘compress’ format was not designed to allow consistency checks.
122 However ‘gunzip’ is sometimes able to detect a bad ‘.Z’ file. If you
123 get an error when uncompressing a ‘.Z’ file, do not assume that the ‘.Z’
124 file is correct simply because the standard ‘uncompress’ does not
125 complain. This generally means that the standard ‘uncompress’ does not
126 check its input, and happily generates garbage output. The SCO
127 ‘compress -H’ format (LZH compression method) does not include a CRC but
128 also allows some consistency checks.
130 Files created by ‘zip’ can be uncompressed by ‘gzip’ only if they
131 have a single member compressed with the “deflation” method. This
132 feature is only intended to help conversion of ‘tar.zip’ files to the
133 ‘tar.gz’ format. To extract a ‘zip’ file with a single member, use a
134 command like ‘gunzip <foo.zip’ or ‘gunzip -S .zip foo.zip’. To extract
135 ‘zip’ files with several members, use ‘unzip’ instead of ‘gunzip’.
137 ‘zcat’ is identical to ‘gunzip -c’. ‘zcat’ uncompresses either a
138 list of files on the command line or its standard input and writes the
139 uncompressed data on standard output. ‘zcat’ will uncompress files that
140 have the correct magic number whether they have a ‘.gz’ suffix or not.
142 ‘gzip’ uses the Lempel–Ziv algorithm used in ‘zip’ and PKZIP. The
143 amount of compression obtained depends on the size of the input and the
144 distribution of common substrings. Typically, text such as source code
145 or English is reduced by 60–70%. Compression is generally much better
146 than that achieved by LZW (as used in ‘compress’), Huffman coding (as
147 used in ‘pack’), or adaptive Huffman coding (‘compact’).
149 Compression is always performed, even if the compressed file is
150 slightly larger than the original. The worst case expansion is a few
151 bytes for the ‘gzip’ file header, plus 5 bytes every 32K block, or an
152 expansion ratio of 0.015% for large files. Note that the actual number
153 of used disk blocks almost never increases. ‘gzip’ normally preserves
154 the mode, ownership and timestamps of files when compressing or
157 The ‘gzip’ file format is specified in P. Deutsch, GZIP file format
158 specification version 4.3, Internet RFC 1952
159 (https://www.ietf.org/rfc/rfc1952.txt) (May 1996). The ‘zip’ deflation
160 format is specified in P. Deutsch, DEFLATE Compressed Data Format
161 Specification version 1.3, Internet RFC 1951
162 (https://www.ietf.org/rfc/rfc1951.txt) (May 1996).
165 File: gzip.info, Node: Sample, Next: Invoking gzip, Prev: Overview, Up: Top
170 Here are some realistic examples of running ‘gzip’.
172 This is the output of the command ‘gzip -h’:
174 Usage: gzip [OPTION]... [FILE]...
175 Compress or uncompress FILEs (by default, compress FILES in-place).
177 Mandatory arguments to long options are mandatory for short options too.
179 -c, --stdout write on standard output, keep original files unchanged
180 -d, --decompress decompress
181 -f, --force force overwrite of output file and compress links
182 -h, --help give this help
183 -k, --keep keep (don't delete) input files
184 -l, --list list compressed file contents
185 -L, --license display software license
186 -n, --no-name do not save or restore the original name and timestamp
187 -N, --name save or restore the original name and timestamp
188 -q, --quiet suppress all warnings
189 -r, --recursive operate recursively on directories
190 --rsyncable make rsync-friendly archive
191 -S, --suffix=SUF use suffix SUF on compressed files
192 --synchronous synchronous output (safer if system crashes, but slower)
193 -t, --test test compressed file integrity
194 -v, --verbose verbose mode
195 -V, --version display version number
196 -1, --fast compress faster
197 -9, --best compress better
199 With no FILE, or when FILE is -, read standard input.
201 Report bugs to <bug-gzip@gnu.org>.
203 This is the output of the command ‘gzip -v texinfo.tex’:
205 texinfo.tex: 69.3% -- replaced with texinfo.tex.gz
207 The following command will find all regular ‘.gz’ files in the
208 current directory and subdirectories (skipping file names that contain
209 newlines), and extract them in place without destroying the original,
210 stopping on the first failure:
213 *' -prune -o -name '*.gz' -type f -print |
216 s/^\\(.*\\)\\.gz$/gunzip <'\\1.gz' >'\\1'/
221 File: gzip.info, Node: Invoking gzip, Next: Advanced usage, Prev: Sample, Up: Top
226 The format for running the ‘gzip’ program is:
230 ‘gzip’ supports the following options:
235 Write output on standard output; keep original files unchanged. If
236 there are several input files, the output consists of a sequence of
237 independently compressed members. To obtain better compression,
238 concatenate all input files before compressing them.
247 Force compression or decompression even if the file has multiple
248 links or the corresponding file already exists, or if the
249 compressed data is read from or written to a terminal. If the
250 input data is not in a format recognized by ‘gzip’, and if the
251 option ‘--stdout’ is also given, copy the input data without change
252 to the standard output: let ‘zcat’ behave as ‘cat’. If ‘-f’ is not
253 given, and when not running in the background, ‘gzip’ prompts to
254 verify whether an existing file should be overwritten.
258 Print an informative help message describing the options then quit.
262 Keep (don’t delete) input files during compression or
267 For each compressed file, list the following fields:
269 compressed size: size of the compressed file
270 uncompressed size: size of the uncompressed file
271 ratio: compression ratio (0.0% if unknown)
272 uncompressed_name: name of the uncompressed file
274 The uncompressed size is given as −1 for files not in ‘gzip’
275 format, such as compressed ‘.Z’ files. To get the uncompressed
276 size for such a file, you can use:
280 In combination with the ‘--verbose’ option, the following fields
283 method: compression method (deflate,compress,lzh,pack)
284 crc: the 32-bit CRC of the uncompressed data
285 date & time: timestamp for the uncompressed file
287 The CRC is given as ffffffff for a file not in gzip format.
289 With ‘--verbose’, the size totals and compression ratio for all
290 files is also displayed, unless some sizes are unknown. With
291 ‘--quiet’, the title and totals lines are not displayed.
293 The ‘gzip’ format represents the input size modulo 2^32, so the
294 uncompressed size and compression ratio are listed incorrectly for
295 uncompressed files 4 GiB and larger. To work around this problem,
296 you can use the following command to discover a large uncompressed
303 Display the ‘gzip’ license then quit.
307 When compressing, do not save the original file name and timestamp
308 by default. (The original name is always saved if the name had to
309 be truncated.) When decompressing, do not restore the original
310 file name if present (remove only the ‘gzip’ suffix from the
311 compressed file name) and do not restore the original timestamp if
312 present (copy it from the compressed file). This option is the
313 default when decompressing.
317 When compressing, always save the original file name, and save the
318 original timestamp if the original is a regular file; this is the
319 default. When decompressing, restore the original file name and
320 timestamp if present. This option is useful on systems which have
321 a limit on file name length or when the timestamp has been lost
322 after a file transfer.
326 Suppress all warning messages.
330 Travel the directory structure recursively. If any of the file
331 names specified on the command line are directories, ‘gzip’ will
332 descend into the directory and compress all the files it finds
333 there (or decompress them in the case of ‘gunzip’).
336 Cater better to the ‘rsync’ program by periodically resetting the
337 internal structure of the compressed data stream. This lets the
338 ‘rsync’ program take advantage of similarities in the uncompressed
339 input when synchronizing two files compressed with this flag. The
340 cost: the compressed output is usually about one percent larger.
344 Use suffix SUF instead of ‘.gz’. Any suffix can be given, but
345 suffixes other than ‘.z’ and ‘.gz’ should be avoided to avoid
346 confusion when files are transferred to other systems. A null
347 suffix forces gunzip to try decompression on all given files
348 regardless of suffix, as in:
350 gunzip -S "" * (*.* for MSDOS)
352 Previous versions of gzip used the ‘.z’ suffix. This was changed
353 to avoid a conflict with ‘pack’.
356 Use synchronous output, by transferring output data to the output
357 file’s storage device when the file system supports this. Because
358 file system data can be cached, without this option if the system
359 crashes around the time a command like ‘gzip FOO’ is run the user
360 might lose both ‘FOO’ and ‘FOO.gz’; this is the default with
361 ‘gzip’, just as it is the default with most applications that move
362 data. When this option is used, ‘gzip’ is safer but can be
367 Test. Check the compressed file integrity.
371 Verbose. Display the name and percentage reduction for each file
376 Version. Display the version number and compilation options, then
382 Regulate the speed of compression using the specified digit N,
383 where ‘-1’ or ‘--fast’ indicates the fastest compression method
384 (less compression) and ‘--best’ or ‘-9’ indicates the slowest
385 compression method (optimal compression). The default compression
386 level is ‘-6’ (that is, biased towards high compression at expense
390 File: gzip.info, Node: Advanced usage, Next: Environment, Prev: Invoking gzip, Up: Top
395 Multiple compressed files can be concatenated. In this case, ‘gunzip’
396 will extract all members at once. If one member is damaged, other
397 members might still be recovered after removal of the damaged member.
398 Better compression can be usually obtained if all members are
399 decompressed and then recompressed in a single step.
401 This is an example of concatenating ‘gzip’ files:
403 gzip -c file1 > foo.gz
404 gzip -c file2 >> foo.gz
414 In case of damage to one member of a ‘.gz’ file, other members can
415 still be recovered (if the damaged member is removed). However, you can
416 get better compression by compressing all members at once:
418 cat file1 file2 | gzip > foo.gz
420 compresses better than
422 gzip -c file1 file2 > foo.gz
424 If you want to recompress concatenated files to get better
427 zcat old.gz | gzip > new.gz
429 If a compressed file consists of several members, the uncompressed
430 size and CRC reported by the ‘--list’ option applies to the last member
431 only. If you need the uncompressed size for all members, you can use:
435 If you wish to create a single archive file with multiple members so
436 that members can later be extracted independently, use an archiver such
437 as ‘tar’ or ‘zip’. GNU ‘tar’ supports the ‘-z’ option to invoke ‘gzip’
438 transparently. ‘gzip’ is designed as a complement to ‘tar’, not as a
442 File: gzip.info, Node: Environment, Next: Tapes, Prev: Advanced usage, Up: Top
447 The obsolescent environment variable ‘GZIP’ can hold a set of default
448 options for ‘gzip’. These options are interpreted first and can be
449 overwritten by explicit command line parameters. As this can cause
450 problems when using scripts, this feature is supported only for options
451 that are reasonably likely to not cause too much harm, and ‘gzip’ warns
452 if it is used. This feature will be removed in a future release of
455 You can use an alias or script instead. For example, if ‘gzip’ is in
456 the directory ‘/usr/bin’ you can prepend ‘$HOME/bin’ to your ‘PATH’ and
457 create an executable script ‘$HOME/bin/gzip’ containing the following:
464 File: gzip.info, Node: Tapes, Next: Problems, Prev: Environment, Up: Top
466 6 Using ‘gzip’ on tapes
467 ***********************
469 When writing compressed data to a tape, it is generally necessary to pad
470 the output with zeroes up to a block boundary. When the data is read
471 and the whole block is passed to ‘gunzip’ for decompression, ‘gunzip’
472 detects that there is extra trailing garbage after the compressed data
473 and emits a warning by default if the garbage contains nonzero bytes.
474 You can use the ‘--quiet’ option to suppress the warning.
477 File: gzip.info, Node: Problems, Next: GNU Free Documentation License, Prev: Tapes, Up: Top
482 If you find a bug in ‘gzip’, please send electronic mail to
483 <bug-gzip@gnu.org>. Include the version number, which you can find by
484 running ‘gzip -V’. Also include in your message the hardware and
485 operating system, the compiler used to compile ‘gzip’, a description of
486 the bug behavior, and the input to ‘gzip’ that triggered the bug.
489 File: gzip.info, Node: GNU Free Documentation License, Next: Concept index, Prev: Problems, Up: Top
491 Appendix A GNU Free Documentation License
492 *****************************************
494 Version 1.3, 3 November 2008
496 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
499 Everyone is permitted to copy and distribute verbatim copies
500 of this license document, but changing it is not allowed.
504 The purpose of this License is to make a manual, textbook, or other
505 functional and useful document “free” in the sense of freedom: to
506 assure everyone the effective freedom to copy and redistribute it,
507 with or without modifying it, either commercially or
508 noncommercially. Secondarily, this License preserves for the
509 author and publisher a way to get credit for their work, while not
510 being considered responsible for modifications made by others.
512 This License is a kind of “copyleft”, which means that derivative
513 works of the document must themselves be free in the same sense.
514 It complements the GNU General Public License, which is a copyleft
515 license designed for free software.
517 We have designed this License in order to use it for manuals for
518 free software, because free software needs free documentation: a
519 free program should come with manuals providing the same freedoms
520 that the software does. But this License is not limited to
521 software manuals; it can be used for any textual work, regardless
522 of subject matter or whether it is published as a printed book. We
523 recommend this License principally for works whose purpose is
524 instruction or reference.
526 1. APPLICABILITY AND DEFINITIONS
528 This License applies to any manual or other work, in any medium,
529 that contains a notice placed by the copyright holder saying it can
530 be distributed under the terms of this License. Such a notice
531 grants a world-wide, royalty-free license, unlimited in duration,
532 to use that work under the conditions stated herein. The
533 “Document”, below, refers to any such manual or work. Any member
534 of the public is a licensee, and is addressed as “you”. You accept
535 the license if you copy, modify or distribute the work in a way
536 requiring permission under copyright law.
538 A “Modified Version” of the Document means any work containing the
539 Document or a portion of it, either copied verbatim, or with
540 modifications and/or translated into another language.
542 A “Secondary Section” is a named appendix or a front-matter section
543 of the Document that deals exclusively with the relationship of the
544 publishers or authors of the Document to the Document’s overall
545 subject (or to related matters) and contains nothing that could
546 fall directly within that overall subject. (Thus, if the Document
547 is in part a textbook of mathematics, a Secondary Section may not
548 explain any mathematics.) The relationship could be a matter of
549 historical connection with the subject or with related matters, or
550 of legal, commercial, philosophical, ethical or political position
553 The “Invariant Sections” are certain Secondary Sections whose
554 titles are designated, as being those of Invariant Sections, in the
555 notice that says that the Document is released under this License.
556 If a section does not fit the above definition of Secondary then it
557 is not allowed to be designated as Invariant. The Document may
558 contain zero Invariant Sections. If the Document does not identify
559 any Invariant Sections then there are none.
561 The “Cover Texts” are certain short passages of text that are
562 listed, as Front-Cover Texts or Back-Cover Texts, in the notice
563 that says that the Document is released under this License. A
564 Front-Cover Text may be at most 5 words, and a Back-Cover Text may
567 A “Transparent” copy of the Document means a machine-readable copy,
568 represented in a format whose specification is available to the
569 general public, that is suitable for revising the document
570 straightforwardly with generic text editors or (for images composed
571 of pixels) generic paint programs or (for drawings) some widely
572 available drawing editor, and that is suitable for input to text
573 formatters or for automatic translation to a variety of formats
574 suitable for input to text formatters. A copy made in an otherwise
575 Transparent file format whose markup, or absence of markup, has
576 been arranged to thwart or discourage subsequent modification by
577 readers is not Transparent. An image format is not Transparent if
578 used for any substantial amount of text. A copy that is not
579 “Transparent” is called “Opaque”.
581 Examples of suitable formats for Transparent copies include plain
582 ASCII without markup, Texinfo input format, LaTeX input format,
583 SGML or XML using a publicly available DTD, and standard-conforming
584 simple HTML, PostScript or PDF designed for human modification.
585 Examples of transparent image formats include PNG, XCF and JPG.
586 Opaque formats include proprietary formats that can be read and
587 edited only by proprietary word processors, SGML or XML for which
588 the DTD and/or processing tools are not generally available, and
589 the machine-generated HTML, PostScript or PDF produced by some word
590 processors for output purposes only.
592 The “Title Page” means, for a printed book, the title page itself,
593 plus such following pages as are needed to hold, legibly, the
594 material this License requires to appear in the title page. For
595 works in formats which do not have any title page as such, “Title
596 Page” means the text near the most prominent appearance of the
597 work’s title, preceding the beginning of the body of the text.
599 The “publisher” means any person or entity that distributes copies
600 of the Document to the public.
602 A section “Entitled XYZ” means a named subunit of the Document
603 whose title either is precisely XYZ or contains XYZ in parentheses
604 following text that translates XYZ in another language. (Here XYZ
605 stands for a specific section name mentioned below, such as
606 “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.)
607 To “Preserve the Title” of such a section when you modify the
608 Document means that it remains a section “Entitled XYZ” according
611 The Document may include Warranty Disclaimers next to the notice
612 which states that this License applies to the Document. These
613 Warranty Disclaimers are considered to be included by reference in
614 this License, but only as regards disclaiming warranties: any other
615 implication that these Warranty Disclaimers may have is void and
616 has no effect on the meaning of this License.
620 You may copy and distribute the Document in any medium, either
621 commercially or noncommercially, provided that this License, the
622 copyright notices, and the license notice saying this License
623 applies to the Document are reproduced in all copies, and that you
624 add no other conditions whatsoever to those of this License. You
625 may not use technical measures to obstruct or control the reading
626 or further copying of the copies you make or distribute. However,
627 you may accept compensation in exchange for copies. If you
628 distribute a large enough number of copies you must also follow the
629 conditions in section 3.
631 You may also lend copies, under the same conditions stated above,
632 and you may publicly display copies.
634 3. COPYING IN QUANTITY
636 If you publish printed copies (or copies in media that commonly
637 have printed covers) of the Document, numbering more than 100, and
638 the Document’s license notice requires Cover Texts, you must
639 enclose the copies in covers that carry, clearly and legibly, all
640 these Cover Texts: Front-Cover Texts on the front cover, and
641 Back-Cover Texts on the back cover. Both covers must also clearly
642 and legibly identify you as the publisher of these copies. The
643 front cover must present the full title with all words of the title
644 equally prominent and visible. You may add other material on the
645 covers in addition. Copying with changes limited to the covers, as
646 long as they preserve the title of the Document and satisfy these
647 conditions, can be treated as verbatim copying in other respects.
649 If the required texts for either cover are too voluminous to fit
650 legibly, you should put the first ones listed (as many as fit
651 reasonably) on the actual cover, and continue the rest onto
654 If you publish or distribute Opaque copies of the Document
655 numbering more than 100, you must either include a machine-readable
656 Transparent copy along with each Opaque copy, or state in or with
657 each Opaque copy a computer-network location from which the general
658 network-using public has access to download using public-standard
659 network protocols a complete Transparent copy of the Document, free
660 of added material. If you use the latter option, you must take
661 reasonably prudent steps, when you begin distribution of Opaque
662 copies in quantity, to ensure that this Transparent copy will
663 remain thus accessible at the stated location until at least one
664 year after the last time you distribute an Opaque copy (directly or
665 through your agents or retailers) of that edition to the public.
667 It is requested, but not required, that you contact the authors of
668 the Document well before redistributing any large number of copies,
669 to give them a chance to provide you with an updated version of the
674 You may copy and distribute a Modified Version of the Document
675 under the conditions of sections 2 and 3 above, provided that you
676 release the Modified Version under precisely this License, with the
677 Modified Version filling the role of the Document, thus licensing
678 distribution and modification of the Modified Version to whoever
679 possesses a copy of it. In addition, you must do these things in
680 the Modified Version:
682 A. Use in the Title Page (and on the covers, if any) a title
683 distinct from that of the Document, and from those of previous
684 versions (which should, if there were any, be listed in the
685 History section of the Document). You may use the same title
686 as a previous version if the original publisher of that
687 version gives permission.
689 B. List on the Title Page, as authors, one or more persons or
690 entities responsible for authorship of the modifications in
691 the Modified Version, together with at least five of the
692 principal authors of the Document (all of its principal
693 authors, if it has fewer than five), unless they release you
694 from this requirement.
696 C. State on the Title page the name of the publisher of the
697 Modified Version, as the publisher.
699 D. Preserve all the copyright notices of the Document.
701 E. Add an appropriate copyright notice for your modifications
702 adjacent to the other copyright notices.
704 F. Include, immediately after the copyright notices, a license
705 notice giving the public permission to use the Modified
706 Version under the terms of this License, in the form shown in
709 G. Preserve in that license notice the full lists of Invariant
710 Sections and required Cover Texts given in the Document’s
713 H. Include an unaltered copy of this License.
715 I. Preserve the section Entitled “History”, Preserve its Title,
716 and add to it an item stating at least the title, year, new
717 authors, and publisher of the Modified Version as given on the
718 Title Page. If there is no section Entitled “History” in the
719 Document, create one stating the title, year, authors, and
720 publisher of the Document as given on its Title Page, then add
721 an item describing the Modified Version as stated in the
724 J. Preserve the network location, if any, given in the Document
725 for public access to a Transparent copy of the Document, and
726 likewise the network locations given in the Document for
727 previous versions it was based on. These may be placed in the
728 “History” section. You may omit a network location for a work
729 that was published at least four years before the Document
730 itself, or if the original publisher of the version it refers
733 K. For any section Entitled “Acknowledgements” or “Dedications”,
734 Preserve the Title of the section, and preserve in the section
735 all the substance and tone of each of the contributor
736 acknowledgements and/or dedications given therein.
738 L. Preserve all the Invariant Sections of the Document, unaltered
739 in their text and in their titles. Section numbers or the
740 equivalent are not considered part of the section titles.
742 M. Delete any section Entitled “Endorsements”. Such a section
743 may not be included in the Modified Version.
745 N. Do not retitle any existing section to be Entitled
746 “Endorsements” or to conflict in title with any Invariant
749 O. Preserve any Warranty Disclaimers.
751 If the Modified Version includes new front-matter sections or
752 appendices that qualify as Secondary Sections and contain no
753 material copied from the Document, you may at your option designate
754 some or all of these sections as invariant. To do this, add their
755 titles to the list of Invariant Sections in the Modified Version’s
756 license notice. These titles must be distinct from any other
759 You may add a section Entitled “Endorsements”, provided it contains
760 nothing but endorsements of your Modified Version by various
761 parties—for example, statements of peer review or that the text has
762 been approved by an organization as the authoritative definition of
765 You may add a passage of up to five words as a Front-Cover Text,
766 and a passage of up to 25 words as a Back-Cover Text, to the end of
767 the list of Cover Texts in the Modified Version. Only one passage
768 of Front-Cover Text and one of Back-Cover Text may be added by (or
769 through arrangements made by) any one entity. If the Document
770 already includes a cover text for the same cover, previously added
771 by you or by arrangement made by the same entity you are acting on
772 behalf of, you may not add another; but you may replace the old
773 one, on explicit permission from the previous publisher that added
776 The author(s) and publisher(s) of the Document do not by this
777 License give permission to use their names for publicity for or to
778 assert or imply endorsement of any Modified Version.
780 5. COMBINING DOCUMENTS
782 You may combine the Document with other documents released under
783 this License, under the terms defined in section 4 above for
784 modified versions, provided that you include in the combination all
785 of the Invariant Sections of all of the original documents,
786 unmodified, and list them all as Invariant Sections of your
787 combined work in its license notice, and that you preserve all
788 their Warranty Disclaimers.
790 The combined work need only contain one copy of this License, and
791 multiple identical Invariant Sections may be replaced with a single
792 copy. If there are multiple Invariant Sections with the same name
793 but different contents, make the title of each such section unique
794 by adding at the end of it, in parentheses, the name of the
795 original author or publisher of that section if known, or else a
796 unique number. Make the same adjustment to the section titles in
797 the list of Invariant Sections in the license notice of the
800 In the combination, you must combine any sections Entitled
801 “History” in the various original documents, forming one section
802 Entitled “History”; likewise combine any sections Entitled
803 “Acknowledgements”, and any sections Entitled “Dedications”. You
804 must delete all sections Entitled “Endorsements.”
806 6. COLLECTIONS OF DOCUMENTS
808 You may make a collection consisting of the Document and other
809 documents released under this License, and replace the individual
810 copies of this License in the various documents with a single copy
811 that is included in the collection, provided that you follow the
812 rules of this License for verbatim copying of each of the documents
813 in all other respects.
815 You may extract a single document from such a collection, and
816 distribute it individually under this License, provided you insert
817 a copy of this License into the extracted document, and follow this
818 License in all other respects regarding verbatim copying of that
821 7. AGGREGATION WITH INDEPENDENT WORKS
823 A compilation of the Document or its derivatives with other
824 separate and independent documents or works, in or on a volume of a
825 storage or distribution medium, is called an “aggregate” if the
826 copyright resulting from the compilation is not used to limit the
827 legal rights of the compilation’s users beyond what the individual
828 works permit. When the Document is included in an aggregate, this
829 License does not apply to the other works in the aggregate which
830 are not themselves derivative works of the Document.
832 If the Cover Text requirement of section 3 is applicable to these
833 copies of the Document, then if the Document is less than one half
834 of the entire aggregate, the Document’s Cover Texts may be placed
835 on covers that bracket the Document within the aggregate, or the
836 electronic equivalent of covers if the Document is in electronic
837 form. Otherwise they must appear on printed covers that bracket
842 Translation is considered a kind of modification, so you may
843 distribute translations of the Document under the terms of section
844 4. Replacing Invariant Sections with translations requires special
845 permission from their copyright holders, but you may include
846 translations of some or all Invariant Sections in addition to the
847 original versions of these Invariant Sections. You may include a
848 translation of this License, and all the license notices in the
849 Document, and any Warranty Disclaimers, provided that you also
850 include the original English version of this License and the
851 original versions of those notices and disclaimers. In case of a
852 disagreement between the translation and the original version of
853 this License or a notice or disclaimer, the original version will
856 If a section in the Document is Entitled “Acknowledgements”,
857 “Dedications”, or “History”, the requirement (section 4) to
858 Preserve its Title (section 1) will typically require changing the
863 You may not copy, modify, sublicense, or distribute the Document
864 except as expressly provided under this License. Any attempt
865 otherwise to copy, modify, sublicense, or distribute it is void,
866 and will automatically terminate your rights under this License.
868 However, if you cease all violation of this License, then your
869 license from a particular copyright holder is reinstated (a)
870 provisionally, unless and until the copyright holder explicitly and
871 finally terminates your license, and (b) permanently, if the
872 copyright holder fails to notify you of the violation by some
873 reasonable means prior to 60 days after the cessation.
875 Moreover, your license from a particular copyright holder is
876 reinstated permanently if the copyright holder notifies you of the
877 violation by some reasonable means, this is the first time you have
878 received notice of violation of this License (for any work) from
879 that copyright holder, and you cure the violation prior to 30 days
880 after your receipt of the notice.
882 Termination of your rights under this section does not terminate
883 the licenses of parties who have received copies or rights from you
884 under this License. If your rights have been terminated and not
885 permanently reinstated, receipt of a copy of some or all of the
886 same material does not give you any rights to use it.
888 10. FUTURE REVISIONS OF THIS LICENSE
890 The Free Software Foundation may publish new, revised versions of
891 the GNU Free Documentation License from time to time. Such new
892 versions will be similar in spirit to the present version, but may
893 differ in detail to address new problems or concerns. See
894 <https://www.gnu.org/copyleft/>.
896 Each version of the License is given a distinguishing version
897 number. If the Document specifies that a particular numbered
898 version of this License “or any later version” applies to it, you
899 have the option of following the terms and conditions either of
900 that specified version or of any later version that has been
901 published (not as a draft) by the Free Software Foundation. If the
902 Document does not specify a version number of this License, you may
903 choose any version ever published (not as a draft) by the Free
904 Software Foundation. If the Document specifies that a proxy can
905 decide which future versions of this License can be used, that
906 proxy’s public statement of acceptance of a version permanently
907 authorizes you to choose that version for the Document.
911 “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
912 World Wide Web server that publishes copyrightable works and also
913 provides prominent facilities for anybody to edit those works. A
914 public wiki that anybody can edit is an example of such a server.
915 A “Massive Multiauthor Collaboration” (or “MMC”) contained in the
916 site means any set of copyrightable works thus published on the MMC
919 “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0
920 license published by Creative Commons Corporation, a not-for-profit
921 corporation with a principal place of business in San Francisco,
922 California, as well as future copyleft versions of that license
923 published by that same organization.
925 “Incorporate” means to publish or republish a Document, in whole or
926 in part, as part of another Document.
928 An MMC is “eligible for relicensing” if it is licensed under this
929 License, and if all works that were first published under this
930 License somewhere other than this MMC, and subsequently
931 incorporated in whole or in part into the MMC, (1) had no cover
932 texts or invariant sections, and (2) were thus incorporated prior
935 The operator of an MMC Site may republish an MMC contained in the
936 site under CC-BY-SA on the same site at any time before August 1,
937 2009, provided the MMC is eligible for relicensing.
939 ADDENDUM: How to use this License for your documents
940 ====================================================
942 To use this License in a document you have written, include a copy of
943 the License in the document and put the following copyright and license
944 notices just after the title page:
946 Copyright (C) YEAR YOUR NAME.
947 Permission is granted to copy, distribute and/or modify this document
948 under the terms of the GNU Free Documentation License, Version 1.3
949 or any later version published by the Free Software Foundation;
950 with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
951 Texts. A copy of the license is included in the section entitled ``GNU
952 Free Documentation License''.
954 If you have Invariant Sections, Front-Cover Texts and Back-Cover
955 Texts, replace the “with...Texts.” line with this:
957 with the Invariant Sections being LIST THEIR TITLES, with
958 the Front-Cover Texts being LIST, and with the Back-Cover Texts
961 If you have Invariant Sections without Cover Texts, or some other
962 combination of the three, merge those two alternatives to suit the
965 If your document contains nontrivial examples of program code, we
966 recommend releasing these examples in parallel under your choice of free
967 software license, such as the GNU General Public License, to permit
968 their use in free software.
971 File: gzip.info, Node: Concept index, Prev: GNU Free Documentation License, Up: Top
973 Appendix B Concept index
974 ************************
979 * bugs: Problems. (line 6)
980 * concatenated files: Advanced usage. (line 6)
981 * Environment: Environment. (line 6)
982 * invoking: Invoking gzip. (line 6)
983 * options: Invoking gzip. (line 6)
984 * overview: Overview. (line 6)
985 * sample: Sample. (line 6)
986 * tapes: Tapes. (line 6)
992 Node: Overview
\7f2701
994 Node: Invoking gzip
\7f10453
995 Node: Advanced usage
\7f16793
996 Node: Environment
\7f18424
998 Node: Problems
\7f19843
999 Node: GNU Free Documentation License
\7f20329
1000 Node: Concept index
\7f45683