X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=gzip.texi;fp=gzip.texi;h=0000000000000000000000000000000000000000;hb=0d5a754ba8f2cc33e98d48d559f0ad6cd18a43a3;hp=95dffa6afec418394a2895b82cb228e36b15297a;hpb=ad96056bdcf62abd585cdb53768fbabdde75d1b5;p=debian%2Fgzip diff --git a/gzip.texi b/gzip.texi deleted file mode 100644 index 95dffa6..0000000 --- a/gzip.texi +++ /dev/null @@ -1,505 +0,0 @@ -\input texinfo @c -*-texinfo-*- -@c %**start of header -@setfilename gzip.info -@include version.texi -@settitle Gzip User's Manual -@finalout -@setchapternewpage odd -@c %**end of header -@copying -This manual is for Gzip -(version @value{VERSION}, @value{UPDATED}), -and documents commands for compressing and decompressing data. - -Copyright @copyright{} 1998, 1999, 2001, 2002 Free Software -Foundation, Inc. - -Copyright @copyright{} 1992, 1993 Jean-loup Gailly - -@quotation -Permission is granted to copy, distribute and/or modify this document -under the terms of the GNU Free Documentation License, Version 1.1 or -any later version published by the Free Software Foundation; with no -Invariant Sections, with the Front-Cover texts being ``A GNU Manual,'' -and with the Back-Cover Texts as in (a) below. A copy of the -license is included in the section entitled ``GNU Free Documentation -License.'' - -(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify -this GNU Manual, like GNU software. Copies published by the Free -Software Foundation raise funds for GNU development.'' -@end quotation -@end copying - -@c Debian install-info (up through at least version 1.9.20) uses only the -@c first dircategory. Put this one first, as it is more useful in practice. -@dircategory Individual utilities -@direntry -* gzip: (gzip)Invoking gzip. Compress files. -@end direntry - -@dircategory Utilities -@direntry -* Gzip: (gzip). The gzip command for compressing files. -@end direntry - -@titlepage -@title gzip -@subtitle The data compression program -@subtitle for Gzip Version @value{VERSION} -@subtitle @value{UPDATED} -@author by Jean-loup Gailly - -@page -@vskip 0pt plus 1filll -@insertcopying -@end titlepage - -@contents - -@ifnottex -@node Top, , , (dir) -@top Compressing Files - -@insertcopying -@end ifnottex - -@menu -* Overview:: Preliminary information. -* Sample:: Sample output from @code{gzip}. -* Invoking gzip:: How to run @code{gzip}. -* Advanced usage:: Concatenated files. -* Environment:: The @code{GZIP} environment variable -* Tapes:: Using @code{gzip} on tapes. -* Problems:: Reporting bugs. -* Copying This Manual:: How to make copies of this manual. -* Concept Index:: Index of concepts. -@end menu - -@node Overview, Sample, , Top -@chapter Overview -@cindex overview - -@code{gzip} reduces the size of the named files using Lempel-Ziv coding -(LZ77). Whenever possible, each file is replaced by one with the -extension @samp{.gz}, while keeping the same ownership modes, access and -modification times. (The default extension is @samp{-gz} for VMS, -@samp{z} for MSDOS, OS/2 FAT and Atari.) If no files are specified or -if a file name is "-", the standard input is compressed to the standard -output. @code{gzip} will only attempt to compress regular files. In -particular, it will ignore symbolic links. - -If the new file name is too long for its file system, @code{gzip} -truncates it. @code{gzip} attempts to truncate only the parts of the -file name longer than 3 characters. (A part is delimited by dots.) If -the name consists of small parts only, the longest parts are truncated. -For example, if file names are limited to 14 characters, gzip.msdos.exe -is compressed to gzi.msd.exe.gz. Names are not truncated on systems -which do not have a limit on file name length. - -By default, @code{gzip} keeps the original file name and timestamp in -the compressed file. These are used when decompressing the file with the -@samp{-N} option. This is useful when the compressed file name was -truncated or when the time stamp was not preserved after a file -transfer. - -Compressed files can be restored to their original form using @samp{gzip -d} -or @code{gunzip} or @code{zcat}. If the original name saved in the -compressed file is not suitable for its file system, a new name is -constructed from the original one to make it legal. - -@code{gunzip} takes a list of files on its command line and replaces -each file whose name ends with @samp{.gz}, @samp{.z}, @samp{.Z}, -@samp{-gz}, @samp{-z} or @samp{_z} and which begins with the correct -magic number with an uncompressed file without the original extension. -@code{gunzip} also recognizes the special extensions @samp{.tgz} and -@samp{.taz} as shorthands for @samp{.tar.gz} and @samp{.tar.Z} -respectively. When compressing, @code{gzip} uses the @samp{.tgz} -extension if necessary instead of truncating a file with a @samp{.tar} -extension. - -@code{gunzip} can currently decompress files created by @code{gzip}, -@code{zip}, @code{compress} or @code{pack}. The detection of the input -format is automatic. When using the first two formats, @code{gunzip} -checks a 32 bit CRC (cyclic redundancy check). For @code{pack}, -@code{gunzip} checks the uncompressed length. The @code{compress} format -was not designed to allow consistency checks. However @code{gunzip} is -sometimes able to detect a bad @samp{.Z} file. If you get an error when -uncompressing a @samp{.Z} file, do not assume that the @samp{.Z} file is -correct simply because the standard @code{uncompress} does not complain. -This generally means that the standard @code{uncompress} does not check -its input, and happily generates garbage output. The SCO @samp{compress --H} format (@code{lzh} compression method) does not include a CRC but -also allows some consistency checks. - -Files created by @code{zip} can be uncompressed by @code{gzip} only if -they have a single member compressed with the 'deflation' method. This -feature is only intended to help conversion of @code{tar.zip} files to -the @code{tar.gz} format. To extract a @code{zip} file with a single -member, use a command like @samp{gunzip . -@end example - -This is the output of the command @samp{gzip -v texinfo.tex}: - -@example -texinfo.tex: 69.7% -- replaced with texinfo.tex.gz -@end example - -The following command will find all @code{gzip} files in the current -directory and subdirectories, and extract them in place without -destroying the original: - -@example -find . -name '*.gz' -print | sed 's/^\(.*\)[.]gz$/gunzip < "&" > "\1"/' | sh -@end example - -@node Invoking gzip, Advanced usage, Sample, Top -@chapter Invoking @code{gzip} -@cindex invoking -@cindex options - -The format for running the @code{gzip} program is: - -@example -gzip @var{option} @dots{} -@end example - -@code{gzip} supports the following options: - -@table @samp -@item --stdout -@itemx --to-stdout -@itemx -c -Write output on standard output; keep original files unchanged. -If there are several input files, the output consists of a sequence of -independently compressed members. To obtain better compression, -concatenate all input files before compressing them. - -@item --decompress -@itemx --uncompress -@itemx -d -Decompress. - -@item --force -@itemx -f -Force compression or decompression even if the file has multiple links -or the corresponding file already exists, or if the compressed data -is read from or written to a terminal. If the input data is not in -a format recognized by @code{gzip}, and if the option @samp{--stdout} is also -given, copy the input data without change to the standard output: let -@code{zcat} behave as @code{cat}. If @samp{-f} is not given, and -when not running in the background, @code{gzip} prompts to verify -whether an existing file should be overwritten. - -@item --help -@itemx -h -Print an informative help message describing the options then quit. - -@item --list -@itemx -l -For each compressed file, list the following fields: - -@example -compressed size: size of the compressed file -uncompressed size: size of the uncompressed file -ratio: compression ratio (0.0% if unknown) -uncompressed_name: name of the uncompressed file -@end example - -The uncompressed size is given as @samp{-1} for files not in @code{gzip} -format, such as compressed @samp{.Z} files. To get the uncompressed size for -such a file, you can use: - -@example -zcat file.Z | wc -c -@end example - -In combination with the @samp{--verbose} option, the following fields are also -displayed: - -@example -method: compression method (deflate,compress,lzh,pack) -crc: the 32-bit CRC of the uncompressed data -date & time: time stamp for the uncompressed file -@end example - -The crc is given as ffffffff for a file not in gzip format. - -With @samp{--verbose}, the size totals and compression ratio for all files -is also displayed, unless some sizes are unknown. With @samp{--quiet}, -the title and totals lines are not displayed. - -The @code{gzip} format represents the the input size modulo -@math{2^32}, so the uncompressed size and compression ratio are listed -incorrectly for uncompressed files 4 GB and larger. To work around -this problem, you can use the following command to discover a large -uncompressed file's true size: - -@example -zcat file.gz | wc -c -@end example - -@item --license -@itemx -L -Display the @code{gzip} license then quit. - -@item --no-name -@itemx -n -When compressing, do not save the original file name and time stamp by -default. (The original name is always saved if the name had to be -truncated.) When decompressing, do not restore the original file name -if present (remove only the @code{gzip} -suffix from the compressed file name) and do not restore the original -time stamp if present (copy it from the compressed file). This option -is the default when decompressing. - -@item --name -@itemx -N -When compressing, always save the original file name and time stamp; this -is the default. When decompressing, restore the original file name and -time stamp if present. This option is useful on systems which have -a limit on file name length or when the time stamp has been lost after -a file transfer. - -@item --quiet -@itemx -q -Suppress all warning messages. - -@item --recursive -@itemx -r -Travel the directory structure recursively. If any of the file names -specified on the command line are directories, @code{gzip} will descend -into the directory and compress all the files it finds there (or -decompress them in the case of @code{gunzip}). - -@item --suffix @var{suf} -@itemx -S @var{suf} -Use suffix @samp{@var{suf}} instead of @samp{.gz}. Any suffix can be -given, but suffixes other than @samp{.z} and @samp{.gz} should be -avoided to avoid confusion when files are transferred to other systems. -A null suffix forces gunzip to try decompression on all given files -regardless of suffix, as in: - -@example -gunzip -S "" * (*.* for MSDOS) -@end example - -Previous versions of gzip used the @samp{.z} suffix. This was changed to -avoid a conflict with @code{pack}. - -@item --test -@itemx -t -Test. Check the compressed file integrity. - -@item --verbose -@itemx -v -Verbose. Display the name and percentage reduction for each file compressed. - -@item --version -@itemx -V -Version. Display the version number and compilation options, then quit. - -@item --fast -@itemx --best -@itemx -@var{n} -Regulate the speed of compression using the specified digit @var{n}, -where @samp{-1} or @samp{--fast} indicates the fastest compression -method (less compression) and @samp{--best} or @samp{-9} indicates the -slowest compression method (optimal compression). The default -compression level is @samp{-6} (that is, biased towards high compression at -expense of speed). -@end table - -@node Advanced usage, Environment, Invoking gzip, Top -@chapter Advanced usage -@cindex concatenated files - -Multiple compressed files can be concatenated. In this case, -@code{gunzip} will extract all members at once. If one member is -damaged, other members might still be recovered after removal of the -damaged member. Better compression can be usually obtained if all -members are decompressed and then recompressed in a single step. - -This is an example of concatenating @code{gzip} files: - -@example -gzip -c file1 > foo.gz -gzip -c file2 >> foo.gz -@end example - -Then - -@example -gunzip -c foo -@end example - -is equivalent to - -@example -cat file1 file2 -@end example - -In case of damage to one member of a @samp{.gz} file, other members can -still be recovered (if the damaged member is removed). However, -you can get better compression by compressing all members at once: - -@example -cat file1 file2 | gzip > foo.gz -@end example - -compresses better than - -@example -gzip -c file1 file2 > foo.gz -@end example - -If you want to recompress concatenated files to get better compression, do: - -@example -zcat old.gz | gzip > new.gz -@end example - -If a compressed file consists of several members, the uncompressed -size and CRC reported by the @samp{--list} option applies to the last member -only. If you need the uncompressed size for all members, you can use: - -@example -zcat file.gz | wc -c -@end example - -If you wish to create a single archive file with multiple members so -that members can later be extracted independently, use an archiver such -as @code{tar} or @code{zip}. GNU @code{tar} supports the @samp{-z} -option to invoke @code{gzip} transparently. @code{gzip} is designed as a -complement to @code{tar}, not as a replacement. - -@node Environment, Tapes, Advanced usage, Top -@chapter Environment -@cindex Environment - -The environment variable @code{GZIP} can hold a set of default options for -@code{gzip}. These options are interpreted first and can be overwritten by -explicit command line parameters. For example: - -@example -for sh: GZIP="-8v --name"; export GZIP -for csh: setenv GZIP "-8v --name" -for MSDOS: set GZIP=-8v --name -@end example - -On Vax/VMS, the name of the environment variable is @code{GZIP_OPT}, to -avoid a conflict with the symbol set for invocation of the program. - -@node Tapes, Problems, Environment, Top -@chapter Using @code{gzip} on tapes -@cindex tapes - -When writing compressed data to a tape, it is generally necessary to pad -the output with zeroes up to a block boundary. When the data is read and -the whole block is passed to @code{gunzip} for decompression, -@code{gunzip} detects that there is extra trailing garbage after the -compressed data and emits a warning by default if the garbage contains -nonzero bytes. You have to use the -@samp{--quiet} option to suppress the warning. This option can be set in the -@code{GZIP} environment variable, as in: - -@example -for sh: GZIP="-q" tar -xfz --block-compress /dev/rst0 -for csh: (setenv GZIP "-q"; tar -xfz --block-compress /dev/rst0) -@end example - -In the above example, @code{gzip} is invoked implicitly by the @samp{-z} -option of GNU @code{tar}. Make sure that the same block size (@samp{-b} -option of @code{tar}) is used for reading and writing compressed data on -tapes. (This example assumes you are using the GNU version of -@code{tar}.) - -@node Problems, Copying This Manual, Tapes, Top -@chapter Reporting Bugs -@cindex bugs - -If you find a bug in @code{gzip}, please send electronic mail to -@email{bug-gzip@@gnu.org}. Include the version number, -which you can find by running @w{@samp{gzip -V}}. Also include in your -message the hardware and operating system, the compiler used to compile -@code{gzip}, -a description of the bug behavior, and the input to @code{gzip} that triggered -the bug.@refill - -@node Copying This Manual, Concept Index, Problems, Top -@appendix Copying This Manual - -@menu -* GNU Free Documentation License:: License for copying this manual. -@end menu - -@include fdl.texi - -@node Concept Index, , Copying This Manual, Top -@appendix Concept Index - -@printindex cp - -@bye