1 This is gzip.info, produced by makeinfo version 6.3 from gzip.texi.
3 This manual is for GNU Gzip (version 1.9, 7 January 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 1.9, 7 January 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 and timestamp in the
90 compressed file. These are used when decompressing the file with the
91 ‘-N’ option. This is useful when the compressed file name was truncated
92 or when the timestamp was not preserved after a file transfer. However,
93 due to limitations in the current ‘gzip’ file format, fractional seconds
94 are discarded. Also, timestamps must fall within the range 1970-01-01
95 00:00:01 through 2106-02-07 06:28:15 UTC, and hosts whose operating
96 systems use 32-bit timestamps are further restricted to timestamps no
97 later than 2038-01-19 03:14:07 UTC. The upper bounds assume the typical
98 case where leap seconds are ignored.
100 Compressed files can be restored to their original form using ‘gzip
101 -d’ or ‘gunzip’ or ‘zcat’. If the original name saved in the compressed
102 file is not suitable for its file system, a new name is constructed from
103 the original one to make it legal.
105 ‘gunzip’ takes a list of files on its command line and replaces each
106 file whose name ends with ‘.gz’, ‘.z’ ‘-gz’, ‘-z’, or ‘_z’ (ignoring
107 case) and which begins with the correct magic number with an
108 uncompressed file without the original extension. ‘gunzip’ also
109 recognizes the special extensions ‘.tgz’ and ‘.taz’ as shorthands for
110 ‘.tar.gz’ and ‘.tar.Z’ respectively. When compressing, ‘gzip’ uses the
111 ‘.tgz’ extension if necessary instead of truncating a file with a ‘.tar’
114 ‘gunzip’ can currently decompress files created by ‘gzip’, ‘zip’,
115 ‘compress’ or ‘pack’. The detection of the input format is automatic.
116 When using the first two formats, ‘gunzip’ checks a 32 bit CRC (cyclic
117 redundancy check). For ‘pack’, ‘gunzip’ checks the uncompressed length.
118 The ‘compress’ format was not designed to allow consistency checks.
119 However ‘gunzip’ is sometimes able to detect a bad ‘.Z’ file. If you
120 get an error when uncompressing a ‘.Z’ file, do not assume that the ‘.Z’
121 file is correct simply because the standard ‘uncompress’ does not
122 complain. This generally means that the standard ‘uncompress’ does not
123 check its input, and happily generates garbage output. The SCO
124 ‘compress -H’ format (LZH compression method) does not include a CRC but
125 also allows some consistency checks.
127 Files created by ‘zip’ can be uncompressed by ‘gzip’ only if they
128 have a single member compressed with the “deflation” method. This
129 feature is only intended to help conversion of ‘tar.zip’ files to the
130 ‘tar.gz’ format. To extract a ‘zip’ file with a single member, use a
131 command like ‘gunzip <foo.zip’ or ‘gunzip -S .zip foo.zip’. To extract
132 ‘zip’ files with several members, use ‘unzip’ instead of ‘gunzip’.
134 ‘zcat’ is identical to ‘gunzip -c’. ‘zcat’ uncompresses either a
135 list of files on the command line or its standard input and writes the
136 uncompressed data on standard output. ‘zcat’ will uncompress files that
137 have the correct magic number whether they have a ‘.gz’ suffix or not.
139 ‘gzip’ uses the Lempel–Ziv algorithm used in ‘zip’ and PKZIP. The
140 amount of compression obtained depends on the size of the input and the
141 distribution of common substrings. Typically, text such as source code
142 or English is reduced by 60–70%. Compression is generally much better
143 than that achieved by LZW (as used in ‘compress’), Huffman coding (as
144 used in ‘pack’), or adaptive Huffman coding (‘compact’).
146 Compression is always performed, even if the compressed file is
147 slightly larger than the original. The worst case expansion is a few
148 bytes for the ‘gzip’ file header, plus 5 bytes every 32K block, or an
149 expansion ratio of 0.015% for large files. Note that the actual number
150 of used disk blocks almost never increases. ‘gzip’ normally preserves
151 the mode, ownership and timestamps of files when compressing or
154 The ‘gzip’ file format is specified in P. Deutsch, GZIP file format
155 specification version 4.3, Internet RFC 1952
156 (https://www.ietf.org/rfc/rfc1952.txt) (May 1996). The ‘zip’ deflation
157 format is specified in P. Deutsch, DEFLATE Compressed Data Format
158 Specification version 1.3, Internet RFC 1951
159 (https://www.ietf.org/rfc/rfc1951.txt) (May 1996).
162 File: gzip.info, Node: Sample, Next: Invoking gzip, Prev: Overview, Up: Top
167 Here are some realistic examples of running ‘gzip’.
169 This is the output of the command ‘gzip -h’:
171 Usage: gzip [OPTION]... [FILE]...
172 Compress or uncompress FILEs (by default, compress FILES in-place).
174 Mandatory arguments to long options are mandatory for short options too.
176 -c, --stdout write on standard output, keep original files unchanged
177 -d, --decompress decompress
178 -f, --force force overwrite of output file and compress links
179 -h, --help give this help
180 -k, --keep keep (don't delete) input files
181 -l, --list list compressed file contents
182 -L, --license display software license
183 -n, --no-name do not save or restore the original name and timestamp
184 -N, --name save or restore the original name and timestamp
185 -q, --quiet suppress all warnings
186 -r, --recursive operate recursively on directories
187 --rsyncable make rsync-friendly archive
188 -S, --suffix=SUF use suffix SUF on compressed files
189 --synchronous synchronous output (safer if system crashes, but slower)
190 -t, --test test compressed file integrity
191 -v, --verbose verbose mode
192 -V, --version display version number
193 -1, --fast compress faster
194 -9, --best compress better
196 With no FILE, or when FILE is -, read standard input.
198 Report bugs to <bug-gzip@gnu.org>.
200 This is the output of the command ‘gzip -v texinfo.tex’:
202 texinfo.tex: 69.3% -- replaced with texinfo.tex.gz
204 The following command will find all regular ‘.gz’ files in the
205 current directory and subdirectories (skipping file names that contain
206 newlines), and extract them in place without destroying the original,
207 stopping on the first failure:
210 *' -prune -o -name '*.gz' -type f -print |
213 s/^\\(.*\\)\\.gz$/gunzip <'\\1.gz' >'\\1'/
218 File: gzip.info, Node: Invoking gzip, Next: Advanced usage, Prev: Sample, Up: Top
223 The format for running the ‘gzip’ program is:
227 ‘gzip’ supports the following options:
232 Write output on standard output; keep original files unchanged. If
233 there are several input files, the output consists of a sequence of
234 independently compressed members. To obtain better compression,
235 concatenate all input files before compressing them.
244 Force compression or decompression even if the file has multiple
245 links or the corresponding file already exists, or if the
246 compressed data is read from or written to a terminal. If the
247 input data is not in a format recognized by ‘gzip’, and if the
248 option ‘--stdout’ is also given, copy the input data without change
249 to the standard output: let ‘zcat’ behave as ‘cat’. If ‘-f’ is not
250 given, and when not running in the background, ‘gzip’ prompts to
251 verify whether an existing file should be overwritten.
255 Print an informative help message describing the options then quit.
259 Keep (don’t delete) input files during compression or
264 For each compressed file, list the following fields:
266 compressed size: size of the compressed file
267 uncompressed size: size of the uncompressed file
268 ratio: compression ratio (0.0% if unknown)
269 uncompressed_name: name of the uncompressed file
271 The uncompressed size is given as −1 for files not in ‘gzip’
272 format, such as compressed ‘.Z’ files. To get the uncompressed
273 size for such a file, you can use:
277 In combination with the ‘--verbose’ option, the following fields
280 method: compression method (deflate,compress,lzh,pack)
281 crc: the 32-bit CRC of the uncompressed data
282 date & time: timestamp for the uncompressed file
284 The CRC is given as ffffffff for a file not in gzip format.
286 With ‘--verbose’, the size totals and compression ratio for all
287 files is also displayed, unless some sizes are unknown. With
288 ‘--quiet’, the title and totals lines are not displayed.
290 The ‘gzip’ format represents the input size modulo 2^32, so the
291 uncompressed size and compression ratio are listed incorrectly for
292 uncompressed files 4 GiB and larger. To work around this problem,
293 you can use the following command to discover a large uncompressed
300 Display the ‘gzip’ license then quit.
304 When compressing, do not save the original file name and timestamp
305 by default. (The original name is always saved if the name had to
306 be truncated.) When decompressing, do not restore the original
307 file name if present (remove only the ‘gzip’ suffix from the
308 compressed file name) and do not restore the original timestamp if
309 present (copy it from the compressed file). This option is the
310 default when decompressing.
314 When compressing, always save the original file name and timestamp;
315 this is the default. When decompressing, restore the original file
316 name and timestamp if present. This option is useful on systems
317 which have a limit on file name length or when the timestamp has
318 been lost after a file transfer.
322 Suppress all warning messages.
326 Travel the directory structure recursively. If any of the file
327 names specified on the command line are directories, ‘gzip’ will
328 descend into the directory and compress all the files it finds
329 there (or decompress them in the case of ‘gunzip’).
332 Cater better to the ‘rsync’ program by periodically resetting the
333 internal structure of the compressed data stream. This lets the
334 ‘rsync’ program take advantage of similarities in the uncompressed
335 input when synchronizing two files compressed with this flag. The
336 cost: the compressed output is usually about one percent larger.
340 Use suffix SUF instead of ‘.gz’. Any suffix can be given, but
341 suffixes other than ‘.z’ and ‘.gz’ should be avoided to avoid
342 confusion when files are transferred to other systems. A null
343 suffix forces gunzip to try decompression on all given files
344 regardless of suffix, as in:
346 gunzip -S "" * (*.* for MSDOS)
348 Previous versions of gzip used the ‘.z’ suffix. This was changed
349 to avoid a conflict with ‘pack’.
352 Use synchronous output, by transferring output data to the output
353 file’s storage device when the file system supports this. Because
354 file system data can be cached, without this option if the system
355 crashes around the time a command like ‘gzip FOO’ is run the user
356 might lose both ‘FOO’ and ‘FOO.gz’; this is the default with
357 ‘gzip’, just as it is the default with most applications that move
358 data. When this option is used, ‘gzip’ is safer but can be
363 Test. Check the compressed file integrity.
367 Verbose. Display the name and percentage reduction for each file
372 Version. Display the version number and compilation options, then
378 Regulate the speed of compression using the specified digit N,
379 where ‘-1’ or ‘--fast’ indicates the fastest compression method
380 (less compression) and ‘--best’ or ‘-9’ indicates the slowest
381 compression method (optimal compression). The default compression
382 level is ‘-6’ (that is, biased towards high compression at expense
386 File: gzip.info, Node: Advanced usage, Next: Environment, Prev: Invoking gzip, Up: Top
391 Multiple compressed files can be concatenated. In this case, ‘gunzip’
392 will extract all members at once. If one member is damaged, other
393 members might still be recovered after removal of the damaged member.
394 Better compression can be usually obtained if all members are
395 decompressed and then recompressed in a single step.
397 This is an example of concatenating ‘gzip’ files:
399 gzip -c file1 > foo.gz
400 gzip -c file2 >> foo.gz
410 In case of damage to one member of a ‘.gz’ file, other members can
411 still be recovered (if the damaged member is removed). However, you can
412 get better compression by compressing all members at once:
414 cat file1 file2 | gzip > foo.gz
416 compresses better than
418 gzip -c file1 file2 > foo.gz
420 If you want to recompress concatenated files to get better
423 zcat old.gz | gzip > new.gz
425 If a compressed file consists of several members, the uncompressed
426 size and CRC reported by the ‘--list’ option applies to the last member
427 only. If you need the uncompressed size for all members, you can use:
431 If you wish to create a single archive file with multiple members so
432 that members can later be extracted independently, use an archiver such
433 as ‘tar’ or ‘zip’. GNU ‘tar’ supports the ‘-z’ option to invoke ‘gzip’
434 transparently. ‘gzip’ is designed as a complement to ‘tar’, not as a
438 File: gzip.info, Node: Environment, Next: Tapes, Prev: Advanced usage, Up: Top
443 The obsolescent environment variable ‘GZIP’ can hold a set of default
444 options for ‘gzip’. These options are interpreted first and can be
445 overwritten by explicit command line parameters. As this can cause
446 problems when using scripts, this feature is supported only for options
447 that are reasonably likely to not cause too much harm, and ‘gzip’ warns
448 if it is used. This feature will be removed in a future release of
451 You can use an alias or script instead. For example, if ‘gzip’ is in
452 the directory ‘/usr/bin’ you can prepend ‘$HOME/bin’ to your ‘PATH’ and
453 create an executable script ‘$HOME/bin/gzip’ containing the following:
460 File: gzip.info, Node: Tapes, Next: Problems, Prev: Environment, Up: Top
462 6 Using ‘gzip’ on tapes
463 ***********************
465 When writing compressed data to a tape, it is generally necessary to pad
466 the output with zeroes up to a block boundary. When the data is read
467 and the whole block is passed to ‘gunzip’ for decompression, ‘gunzip’
468 detects that there is extra trailing garbage after the compressed data
469 and emits a warning by default if the garbage contains nonzero bytes.
470 You can use the ‘--quiet’ option to suppress the warning.
473 File: gzip.info, Node: Problems, Next: GNU Free Documentation License, Prev: Tapes, Up: Top
478 If you find a bug in ‘gzip’, please send electronic mail to
479 <bug-gzip@gnu.org>. Include the version number, which you can find by
480 running ‘gzip -V’. Also include in your message the hardware and
481 operating system, the compiler used to compile ‘gzip’, a description of
482 the bug behavior, and the input to ‘gzip’ that triggered the bug.
485 File: gzip.info, Node: GNU Free Documentation License, Next: Concept index, Prev: Problems, Up: Top
487 Appendix A GNU Free Documentation License
488 *****************************************
490 Version 1.3, 3 November 2008
492 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
495 Everyone is permitted to copy and distribute verbatim copies
496 of this license document, but changing it is not allowed.
500 The purpose of this License is to make a manual, textbook, or other
501 functional and useful document “free” in the sense of freedom: to
502 assure everyone the effective freedom to copy and redistribute it,
503 with or without modifying it, either commercially or
504 noncommercially. Secondarily, this License preserves for the
505 author and publisher a way to get credit for their work, while not
506 being considered responsible for modifications made by others.
508 This License is a kind of “copyleft”, which means that derivative
509 works of the document must themselves be free in the same sense.
510 It complements the GNU General Public License, which is a copyleft
511 license designed for free software.
513 We have designed this License in order to use it for manuals for
514 free software, because free software needs free documentation: a
515 free program should come with manuals providing the same freedoms
516 that the software does. But this License is not limited to
517 software manuals; it can be used for any textual work, regardless
518 of subject matter or whether it is published as a printed book. We
519 recommend this License principally for works whose purpose is
520 instruction or reference.
522 1. APPLICABILITY AND DEFINITIONS
524 This License applies to any manual or other work, in any medium,
525 that contains a notice placed by the copyright holder saying it can
526 be distributed under the terms of this License. Such a notice
527 grants a world-wide, royalty-free license, unlimited in duration,
528 to use that work under the conditions stated herein. The
529 “Document”, below, refers to any such manual or work. Any member
530 of the public is a licensee, and is addressed as “you”. You accept
531 the license if you copy, modify or distribute the work in a way
532 requiring permission under copyright law.
534 A “Modified Version” of the Document means any work containing the
535 Document or a portion of it, either copied verbatim, or with
536 modifications and/or translated into another language.
538 A “Secondary Section” is a named appendix or a front-matter section
539 of the Document that deals exclusively with the relationship of the
540 publishers or authors of the Document to the Document’s overall
541 subject (or to related matters) and contains nothing that could
542 fall directly within that overall subject. (Thus, if the Document
543 is in part a textbook of mathematics, a Secondary Section may not
544 explain any mathematics.) The relationship could be a matter of
545 historical connection with the subject or with related matters, or
546 of legal, commercial, philosophical, ethical or political position
549 The “Invariant Sections” are certain Secondary Sections whose
550 titles are designated, as being those of Invariant Sections, in the
551 notice that says that the Document is released under this License.
552 If a section does not fit the above definition of Secondary then it
553 is not allowed to be designated as Invariant. The Document may
554 contain zero Invariant Sections. If the Document does not identify
555 any Invariant Sections then there are none.
557 The “Cover Texts” are certain short passages of text that are
558 listed, as Front-Cover Texts or Back-Cover Texts, in the notice
559 that says that the Document is released under this License. A
560 Front-Cover Text may be at most 5 words, and a Back-Cover Text may
563 A “Transparent” copy of the Document means a machine-readable copy,
564 represented in a format whose specification is available to the
565 general public, that is suitable for revising the document
566 straightforwardly with generic text editors or (for images composed
567 of pixels) generic paint programs or (for drawings) some widely
568 available drawing editor, and that is suitable for input to text
569 formatters or for automatic translation to a variety of formats
570 suitable for input to text formatters. A copy made in an otherwise
571 Transparent file format whose markup, or absence of markup, has
572 been arranged to thwart or discourage subsequent modification by
573 readers is not Transparent. An image format is not Transparent if
574 used for any substantial amount of text. A copy that is not
575 “Transparent” is called “Opaque”.
577 Examples of suitable formats for Transparent copies include plain
578 ASCII without markup, Texinfo input format, LaTeX input format,
579 SGML or XML using a publicly available DTD, and standard-conforming
580 simple HTML, PostScript or PDF designed for human modification.
581 Examples of transparent image formats include PNG, XCF and JPG.
582 Opaque formats include proprietary formats that can be read and
583 edited only by proprietary word processors, SGML or XML for which
584 the DTD and/or processing tools are not generally available, and
585 the machine-generated HTML, PostScript or PDF produced by some word
586 processors for output purposes only.
588 The “Title Page” means, for a printed book, the title page itself,
589 plus such following pages as are needed to hold, legibly, the
590 material this License requires to appear in the title page. For
591 works in formats which do not have any title page as such, “Title
592 Page” means the text near the most prominent appearance of the
593 work’s title, preceding the beginning of the body of the text.
595 The “publisher” means any person or entity that distributes copies
596 of the Document to the public.
598 A section “Entitled XYZ” means a named subunit of the Document
599 whose title either is precisely XYZ or contains XYZ in parentheses
600 following text that translates XYZ in another language. (Here XYZ
601 stands for a specific section name mentioned below, such as
602 “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.)
603 To “Preserve the Title” of such a section when you modify the
604 Document means that it remains a section “Entitled XYZ” according
607 The Document may include Warranty Disclaimers next to the notice
608 which states that this License applies to the Document. These
609 Warranty Disclaimers are considered to be included by reference in
610 this License, but only as regards disclaiming warranties: any other
611 implication that these Warranty Disclaimers may have is void and
612 has no effect on the meaning of this License.
616 You may copy and distribute the Document in any medium, either
617 commercially or noncommercially, provided that this License, the
618 copyright notices, and the license notice saying this License
619 applies to the Document are reproduced in all copies, and that you
620 add no other conditions whatsoever to those of this License. You
621 may not use technical measures to obstruct or control the reading
622 or further copying of the copies you make or distribute. However,
623 you may accept compensation in exchange for copies. If you
624 distribute a large enough number of copies you must also follow the
625 conditions in section 3.
627 You may also lend copies, under the same conditions stated above,
628 and you may publicly display copies.
630 3. COPYING IN QUANTITY
632 If you publish printed copies (or copies in media that commonly
633 have printed covers) of the Document, numbering more than 100, and
634 the Document’s license notice requires Cover Texts, you must
635 enclose the copies in covers that carry, clearly and legibly, all
636 these Cover Texts: Front-Cover Texts on the front cover, and
637 Back-Cover Texts on the back cover. Both covers must also clearly
638 and legibly identify you as the publisher of these copies. The
639 front cover must present the full title with all words of the title
640 equally prominent and visible. You may add other material on the
641 covers in addition. Copying with changes limited to the covers, as
642 long as they preserve the title of the Document and satisfy these
643 conditions, can be treated as verbatim copying in other respects.
645 If the required texts for either cover are too voluminous to fit
646 legibly, you should put the first ones listed (as many as fit
647 reasonably) on the actual cover, and continue the rest onto
650 If you publish or distribute Opaque copies of the Document
651 numbering more than 100, you must either include a machine-readable
652 Transparent copy along with each Opaque copy, or state in or with
653 each Opaque copy a computer-network location from which the general
654 network-using public has access to download using public-standard
655 network protocols a complete Transparent copy of the Document, free
656 of added material. If you use the latter option, you must take
657 reasonably prudent steps, when you begin distribution of Opaque
658 copies in quantity, to ensure that this Transparent copy will
659 remain thus accessible at the stated location until at least one
660 year after the last time you distribute an Opaque copy (directly or
661 through your agents or retailers) of that edition to the public.
663 It is requested, but not required, that you contact the authors of
664 the Document well before redistributing any large number of copies,
665 to give them a chance to provide you with an updated version of the
670 You may copy and distribute a Modified Version of the Document
671 under the conditions of sections 2 and 3 above, provided that you
672 release the Modified Version under precisely this License, with the
673 Modified Version filling the role of the Document, thus licensing
674 distribution and modification of the Modified Version to whoever
675 possesses a copy of it. In addition, you must do these things in
676 the Modified Version:
678 A. Use in the Title Page (and on the covers, if any) a title
679 distinct from that of the Document, and from those of previous
680 versions (which should, if there were any, be listed in the
681 History section of the Document). You may use the same title
682 as a previous version if the original publisher of that
683 version gives permission.
685 B. List on the Title Page, as authors, one or more persons or
686 entities responsible for authorship of the modifications in
687 the Modified Version, together with at least five of the
688 principal authors of the Document (all of its principal
689 authors, if it has fewer than five), unless they release you
690 from this requirement.
692 C. State on the Title page the name of the publisher of the
693 Modified Version, as the publisher.
695 D. Preserve all the copyright notices of the Document.
697 E. Add an appropriate copyright notice for your modifications
698 adjacent to the other copyright notices.
700 F. Include, immediately after the copyright notices, a license
701 notice giving the public permission to use the Modified
702 Version under the terms of this License, in the form shown in
705 G. Preserve in that license notice the full lists of Invariant
706 Sections and required Cover Texts given in the Document’s
709 H. Include an unaltered copy of this License.
711 I. Preserve the section Entitled “History”, Preserve its Title,
712 and add to it an item stating at least the title, year, new
713 authors, and publisher of the Modified Version as given on the
714 Title Page. If there is no section Entitled “History” in the
715 Document, create one stating the title, year, authors, and
716 publisher of the Document as given on its Title Page, then add
717 an item describing the Modified Version as stated in the
720 J. Preserve the network location, if any, given in the Document
721 for public access to a Transparent copy of the Document, and
722 likewise the network locations given in the Document for
723 previous versions it was based on. These may be placed in the
724 “History” section. You may omit a network location for a work
725 that was published at least four years before the Document
726 itself, or if the original publisher of the version it refers
729 K. For any section Entitled “Acknowledgements” or “Dedications”,
730 Preserve the Title of the section, and preserve in the section
731 all the substance and tone of each of the contributor
732 acknowledgements and/or dedications given therein.
734 L. Preserve all the Invariant Sections of the Document, unaltered
735 in their text and in their titles. Section numbers or the
736 equivalent are not considered part of the section titles.
738 M. Delete any section Entitled “Endorsements”. Such a section
739 may not be included in the Modified Version.
741 N. Do not retitle any existing section to be Entitled
742 “Endorsements” or to conflict in title with any Invariant
745 O. Preserve any Warranty Disclaimers.
747 If the Modified Version includes new front-matter sections or
748 appendices that qualify as Secondary Sections and contain no
749 material copied from the Document, you may at your option designate
750 some or all of these sections as invariant. To do this, add their
751 titles to the list of Invariant Sections in the Modified Version’s
752 license notice. These titles must be distinct from any other
755 You may add a section Entitled “Endorsements”, provided it contains
756 nothing but endorsements of your Modified Version by various
757 parties—for example, statements of peer review or that the text has
758 been approved by an organization as the authoritative definition of
761 You may add a passage of up to five words as a Front-Cover Text,
762 and a passage of up to 25 words as a Back-Cover Text, to the end of
763 the list of Cover Texts in the Modified Version. Only one passage
764 of Front-Cover Text and one of Back-Cover Text may be added by (or
765 through arrangements made by) any one entity. If the Document
766 already includes a cover text for the same cover, previously added
767 by you or by arrangement made by the same entity you are acting on
768 behalf of, you may not add another; but you may replace the old
769 one, on explicit permission from the previous publisher that added
772 The author(s) and publisher(s) of the Document do not by this
773 License give permission to use their names for publicity for or to
774 assert or imply endorsement of any Modified Version.
776 5. COMBINING DOCUMENTS
778 You may combine the Document with other documents released under
779 this License, under the terms defined in section 4 above for
780 modified versions, provided that you include in the combination all
781 of the Invariant Sections of all of the original documents,
782 unmodified, and list them all as Invariant Sections of your
783 combined work in its license notice, and that you preserve all
784 their Warranty Disclaimers.
786 The combined work need only contain one copy of this License, and
787 multiple identical Invariant Sections may be replaced with a single
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789 but different contents, make the title of each such section unique
790 by adding at the end of it, in parentheses, the name of the
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793 the list of Invariant Sections in the license notice of the
796 In the combination, you must combine any sections Entitled
797 “History” in the various original documents, forming one section
798 Entitled “History”; likewise combine any sections Entitled
799 “Acknowledgements”, and any sections Entitled “Dedications”. You
800 must delete all sections Entitled “Endorsements.”
802 6. COLLECTIONS OF DOCUMENTS
804 You may make a collection consisting of the Document and other
805 documents released under this License, and replace the individual
806 copies of this License in the various documents with a single copy
807 that is included in the collection, provided that you follow the
808 rules of this License for verbatim copying of each of the documents
809 in all other respects.
811 You may extract a single document from such a collection, and
812 distribute it individually under this License, provided you insert
813 a copy of this License into the extracted document, and follow this
814 License in all other respects regarding verbatim copying of that
817 7. AGGREGATION WITH INDEPENDENT WORKS
819 A compilation of the Document or its derivatives with other
820 separate and independent documents or works, in or on a volume of a
821 storage or distribution medium, is called an “aggregate” if the
822 copyright resulting from the compilation is not used to limit the
823 legal rights of the compilation’s users beyond what the individual
824 works permit. When the Document is included in an aggregate, this
825 License does not apply to the other works in the aggregate which
826 are not themselves derivative works of the Document.
828 If the Cover Text requirement of section 3 is applicable to these
829 copies of the Document, then if the Document is less than one half
830 of the entire aggregate, the Document’s Cover Texts may be placed
831 on covers that bracket the Document within the aggregate, or the
832 electronic equivalent of covers if the Document is in electronic
833 form. Otherwise they must appear on printed covers that bracket
838 Translation is considered a kind of modification, so you may
839 distribute translations of the Document under the terms of section
840 4. Replacing Invariant Sections with translations requires special
841 permission from their copyright holders, but you may include
842 translations of some or all Invariant Sections in addition to the
843 original versions of these Invariant Sections. You may include a
844 translation of this License, and all the license notices in the
845 Document, and any Warranty Disclaimers, provided that you also
846 include the original English version of this License and the
847 original versions of those notices and disclaimers. In case of a
848 disagreement between the translation and the original version of
849 this License or a notice or disclaimer, the original version will
852 If a section in the Document is Entitled “Acknowledgements”,
853 “Dedications”, or “History”, the requirement (section 4) to
854 Preserve its Title (section 1) will typically require changing the
859 You may not copy, modify, sublicense, or distribute the Document
860 except as expressly provided under this License. Any attempt
861 otherwise to copy, modify, sublicense, or distribute it is void,
862 and will automatically terminate your rights under this License.
864 However, if you cease all violation of this License, then your
865 license from a particular copyright holder is reinstated (a)
866 provisionally, unless and until the copyright holder explicitly and
867 finally terminates your license, and (b) permanently, if the
868 copyright holder fails to notify you of the violation by some
869 reasonable means prior to 60 days after the cessation.
871 Moreover, your license from a particular copyright holder is
872 reinstated permanently if the copyright holder notifies you of the
873 violation by some reasonable means, this is the first time you have
874 received notice of violation of this License (for any work) from
875 that copyright holder, and you cure the violation prior to 30 days
876 after your receipt of the notice.
878 Termination of your rights under this section does not terminate
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881 permanently reinstated, receipt of a copy of some or all of the
882 same material does not give you any rights to use it.
884 10. FUTURE REVISIONS OF THIS LICENSE
886 The Free Software Foundation may publish new, revised versions of
887 the GNU Free Documentation License from time to time. Such new
888 versions will be similar in spirit to the present version, but may
889 differ in detail to address new problems or concerns. See
890 <https://www.gnu.org/copyleft/>.
892 Each version of the License is given a distinguishing version
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895 have the option of following the terms and conditions either of
896 that specified version or of any later version that has been
897 published (not as a draft) by the Free Software Foundation. If the
898 Document does not specify a version number of this License, you may
899 choose any version ever published (not as a draft) by the Free
900 Software Foundation. If the Document specifies that a proxy can
901 decide which future versions of this License can be used, that
902 proxy’s public statement of acceptance of a version permanently
903 authorizes you to choose that version for the Document.
907 “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
908 World Wide Web server that publishes copyrightable works and also
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915 “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0
916 license published by Creative Commons Corporation, a not-for-profit
917 corporation with a principal place of business in San Francisco,
918 California, as well as future copyleft versions of that license
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921 “Incorporate” means to publish or republish a Document, in whole or
922 in part, as part of another Document.
924 An MMC is “eligible for relicensing” if it is licensed under this
925 License, and if all works that were first published under this
926 License somewhere other than this MMC, and subsequently
927 incorporated in whole or in part into the MMC, (1) had no cover
928 texts or invariant sections, and (2) were thus incorporated prior
931 The operator of an MMC Site may republish an MMC contained in the
932 site under CC-BY-SA on the same site at any time before August 1,
933 2009, provided the MMC is eligible for relicensing.
935 ADDENDUM: How to use this License for your documents
936 ====================================================
938 To use this License in a document you have written, include a copy of
939 the License in the document and put the following copyright and license
940 notices just after the title page:
942 Copyright (C) YEAR YOUR NAME.
943 Permission is granted to copy, distribute and/or modify this document
944 under the terms of the GNU Free Documentation License, Version 1.3
945 or any later version published by the Free Software Foundation;
946 with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
947 Texts. A copy of the license is included in the section entitled ``GNU
948 Free Documentation License''.
950 If you have Invariant Sections, Front-Cover Texts and Back-Cover
951 Texts, replace the “with...Texts.” line with this:
953 with the Invariant Sections being LIST THEIR TITLES, with
954 the Front-Cover Texts being LIST, and with the Back-Cover Texts
957 If you have Invariant Sections without Cover Texts, or some other
958 combination of the three, merge those two alternatives to suit the
961 If your document contains nontrivial examples of program code, we
962 recommend releasing these examples in parallel under your choice of free
963 software license, such as the GNU General Public License, to permit
964 their use in free software.
967 File: gzip.info, Node: Concept index, Prev: GNU Free Documentation License, Up: Top
969 Appendix B Concept index
970 ************************
975 * bugs: Problems. (line 6)
976 * concatenated files: Advanced usage. (line 6)
977 * Environment: Environment. (line 6)
978 * invoking: Invoking gzip. (line 6)
979 * options: Invoking gzip. (line 6)
980 * overview: Overview. (line 6)
981 * sample: Sample. (line 6)
982 * tapes: Tapes. (line 6)
988 Node: Overview
\7f2701
990 Node: Invoking gzip
\7f10308
991 Node: Advanced usage
\7f16590
992 Node: Environment
\7f18221
994 Node: Problems
\7f19640
995 Node: GNU Free Documentation License
\7f20126
996 Node: Concept index
\7f45480