X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=gzip.doc;h=da8dad1ad6b06b4beeeee0a30b2c559f69077ebd;hb=dc84183747ce1703eb99685b5dbde1f65a143c06;hp=e730a1cd8b20a617a4062b5e04ad5cbb07569444;hpb=a2016c1de6e4884f6c8ed5cc498f3bf821c25ca4;p=debian%2Fgzip diff --git a/gzip.doc b/gzip.doc index e730a1c..da8dad1 100644 --- a/gzip.doc +++ b/gzip.doc @@ -1,126 +1,126 @@ GZIP(1) GZIP(1) -NAME +1mNAME0m gzip, gunzip, zcat - compress or expand files -SYNOPSIS - gzip [ -acdfhlLnNrtvV19 ] [-S suffix] [ name ... ] - gunzip [ -acfhlLnNrtvV ] [-S suffix] [ name ... ] - zcat [ -fhLV ] [ name ... ] +1mSYNOPSIS0m + 1mgzip 22m[ 1m-acdfhlLnNrtvV19 22m] [1m-S suffix22m] [ 4mname24m 4m...24m ] + 1mgunzip 22m[ 1m-acfhlLnNrtvV 22m] [1m-S suffix22m] [ 4mname24m 4m...24m ] + 1mzcat 22m[ 1m-fhLV 22m] [ 4mname24m 4m...24m ] -DESCRIPTION - Gzip reduces the size of the named files using Lempel-Ziv coding +1mDESCRIPTION0m + 4mGzip24m reduces the size of the named files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the - extension .gz, while keeping the same ownership modes, access and modi- - fication times. (The default extension is -gz for VMS, z for MSDOS, + extension 1m.gz, 22mwhile keeping the same ownership modes, access and modi- + fication times. (The default extension is 1m-gz 22mfor VMS, 1mz 22mfor MSDOS, OS/2 FAT, Windows NT FAT and Atari.) If no files are specified, or if a file name is "-", the standard input is compressed to the standard - output. Gzip will only attempt to compress regular files. In particu- + output. 4mGzip24m will only attempt to compress regular files. In particu- lar, it will ignore symbolic links. - If the compressed file name is too long for its file system, gzip trun- - cates it. Gzip attempts to truncate only the parts of the file name + If the compressed file name is too long for its file system, 4mgzip24m trun- + cates it. 4mGzip24m 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, gzip keeps the original file name and timestamp in the com- - pressed file. These are used when decompressing the file with the -N + By default, 4mgzip24m keeps the original file name and timestamp in the com- + pressed file. These are used when decompressing the file with the 1m-N0m 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 gzip -d - or gunzip or zcat. If the original name saved in the compressed file + Compressed files can be restored to their original form using 4mgzip24m 4m-d0m + or 4mgunzip24m or 4mzcat.24m 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. - gunzip takes a list of files on its command line and replaces each file + 4mgunzip24m takes a list of files on its command line and replaces each file whose name ends with .gz, -gz, .z, -z, or _z (ignoring case) and which begins with the correct magic number with an uncompressed file without - the original extension. gunzip also recognizes the special extensions - .tgz and .taz as shorthands for .tar.gz and .tar.Z respectively. When - compressing, gzip uses the .tgz extension if necessary instead of trun- - cating a file with a .tar extension. - - gunzip can currently decompress files created by gzip, zip, compress, - compress -H or pack. The detection of the input format is automatic. - When using the first two formats, gunzip checks a 32 bit CRC. For pack, - gunzip checks the uncompressed length. The standard compress format was - not designed to allow consistency checks. However gunzip is sometimes + the original extension. 4mgunzip24m also recognizes the special extensions + 1m.tgz 22mand 1m.taz 22mas shorthands for 1m.tar.gz 22mand 1m.tar.Z 22mrespectively. When + compressing, 4mgzip24m uses the 1m.tgz 22mextension if necessary instead of trun- + cating a file with a 1m.tar 22mextension. + + 4mgunzip24m can currently decompress files created by 4mgzip,24m 4mzip,24m 4mcompress,0m + 4mcompress24m 4m-H24m or 4mpack.24m The detection of the input format is automatic. + When using the first two formats, 4mgunzip24m checks a 32 bit CRC. For 4mpack,0m + 4mgunzip24m checks the uncompressed length. The standard 4mcompress24m format was + not designed to allow consistency checks. However 4mgunzip24m is sometimes able to detect a bad .Z file. If you get an error when uncompressing a .Z file, do not assume that the .Z file is correct simply because the - standard uncompress does not complain. This generally means that the - standard uncompress does not check its input, and happily generates + standard 4muncompress24m does not complain. This generally means that the + standard 4muncompress24m does not check its input, and happily generates garbage output. The SCO compress -H format (lzh compression method) does not include a CRC but also allows some consistency checks. - Files created by zip can be uncompressed by gzip only if they have a + Files created by 4mzip24m can be uncompressed by gzip only if they have a single member compressed with the 'deflation' method. This feature is only intended to help conversion of tar.zip files to the tar.gz format. - To extract a zip file with a single member, use a command like gunzip - , Inter- - net RFC 1952 (May 1996). The zip deflation format is specified in P. + net RFC 1952 (May 1996). The 4mzip24m deflation format is specified in P. Deutsch, DEFLATE Compressed Data Format Specification version 1.3, , Internet RFC 1951 (May 1996). -OPTIONS - -a --ascii - Ascii text mode: convert end-of-lines using local conventions. - This option is supported only on some non-Unix systems. For +1mOPTIONS0m + 1m-a --ascii0m + Ascii text mode: convert end-of-lines using local conventions. + This option is supported only on some non-Unix systems. For MSDOS, CR LF is converted to LF when compressing, and LF is con- verted to CR LF when decompressing. - -c --stdout --to-stdout - 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 + 1m-c --stdout --to-stdout0m + 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. - -d --decompress --uncompress + 1m-d --decompress --uncompress0m Decompress. - -f --force + 1m-f --force0m Force compression or decompression even if the file has multiple - links or the corresponding file already exists, or if the com- + links or the corresponding file already exists, or if the com- pressed data is read from or written to a terminal. If the input - data is not in a format recognized by gzip, and if the option - --stdout is also given, copy the input data without change to - the standard output: let zcat behave as cat. If -f is not - given, and when not running in the background, gzip prompts to + data is not in a format recognized by 4mgzip,24m and if the option + --stdout is also given, copy the input data without change to + the standard output: let 4mzcat24m behave as 4mcat.24m If 1m-f 22mis not + given, and when not running in the background, 4mgzip24m prompts to verify whether an existing file should be overwritten. - -h --help + 1m-h --help0m Display a help screen and quit. - -l --list + 1m-l --list0m For each compressed file, list the following fields: compressed size: size of the compressed file @@ -128,91 +128,91 @@ OPTIONS ratio: compression ratio (0.0% if unknown) uncompressed_name: name of the uncompressed file - The uncompressed size is given as -1 for files not in gzip for- - mat, such as compressed .Z files. To get the uncompressed size + The uncompressed size is given as -1 for files not in gzip for- + mat, such as compressed .Z files. To get the uncompressed size for such a file, you can use: zcat file.Z | wc -c - In combination with the --verbose option, the following fields + In combination with the --verbose option, the following fields are also displayed: method: compression method crc: the 32-bit CRC of the uncompressed data date & time: time stamp for the uncompressed file - The compression methods currently supported are deflate, com- - press, lzh (SCO compress -H) and pack. The crc is given as + The compression methods currently supported are deflate, com- + press, lzh (SCO compress -H) and pack. The crc is given as ffffffff for a file not in gzip format. - With --name, the uncompressed name, date and time are those + With --name, the uncompressed name, date and time are those stored within the compress file if present. - With --verbose, the size totals and compression ratio for all - files is also displayed, unless some sizes are unknown. With + With --verbose, the size totals and compression ratio for all + files is also displayed, unless some sizes are unknown. With --quiet, the title and totals lines are not displayed. - -L --license - Display the gzip license and quit. + 1m-L --license0m + Display the 4mgzip24m license and quit. - -n --no-name - When compressing, do not save the original file name and time + 1m-n --no-name0m + 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 gzip suffix from - the compressed file name) and do not restore the original time + had to be truncated.) When decompressing, do not restore the + original file name if present (remove only the 4mgzip24m 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. - -N --name - 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 + 1m-N --name0m + 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. - -q --quiet + 1m-q --quiet0m Suppress all warnings. - -r --recursive - Travel the directory structure recursively. If any of the file - names specified on the command line are directories, gzip will - descend into the directory and compress all the files it finds - there (or decompress them in the case of gunzip ). + 1m-r --recursive0m + Travel the directory structure recursively. If any of the file + names specified on the command line are directories, 4mgzip24m will + descend into the directory and compress all the files it finds + there (or decompress them in the case of 4mgunzip24m ). - -S .suf --suffix .suf - Use suffix .suf instead of .gz. Any suffix can be given, but - suffixes other than .z and .gz should be avoided to avoid confu- - sion when files are transferred to other systems. A null suffix - forces gunzip to try decompression on all given files regard- - less of suffix, as in: + 1m-S .suf --suffix .suf0m + When compressing, use suffix .suf instead of .gz. Any non-empty + suffix can be given, but suffixes other than .z and .gz should + be avoided to avoid confusion when files are transferred to + other systems. - gunzip -S "" * (*.* for MSDOS) + When decompressing, add .suf to the beginning of the list of + suffixes to try, when deriving an output file name from an input + file name. - Previous versions of gzip used the .z suffix. This was changed - to avoid a conflict with pack(1). + 4mpack24m(1)4m.0m - -t --test + 1m-t --test0m Test. Check the compressed file integrity. - -v --verbose + 1m-v --verbose0m Verbose. Display the name and percentage reduction for each file compressed or decompressed. - -V --version + 1m-V --version0m Version. Display the version number and compilation options then quit. - -# --fast --best - Regulate the speed of compression using the specified digit #, - where -1 or --fast indicates the fastest compression method - (less compression) and -9 or --best indicates the slowest com- - pression method (best compression). The default compression - level is -6 (that is, biased towards high compression at expense + 1m-# --fast --best0m + Regulate the speed of compression using the specified digit 4m#24m, + where 1m-1 22mor 1m--fast 22mindicates the fastest compression method + (less compression) and 1m-9 22mor 1m--best 22mindicates the slowest com- + pression method (best compression). The default compression + level is 1m-6 22m(that is, biased towards high compression at expense of speed). -ADVANCED USAGE - Multiple compressed files can be concatenated. In this case, gunzip +1mADVANCED USAGE0m + Multiple compressed files can be concatenated. In this case, 4mgunzip0m will extract all members at once. For example: gzip -c file1 > foo.gz @@ -226,8 +226,8 @@ ADVANCED USAGE cat file1 file2 - In case of damage to one member of a .gz file, other members can still - be recovered (if the damaged member is removed). However, you can get + In case of damage to one member of a .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: cat file1 file2 | gzip > foo.gz @@ -242,64 +242,64 @@ ADVANCED USAGE gzip -cd old.gz | gzip > new.gz If a compressed file consists of several members, the uncompressed size - and CRC reported by the --list option applies to the last member only. + and CRC reported by the --list option applies to the last member only. If you need the uncompressed size for all members, you can use: gzip -cd file.gz | wc -c - If you wish to create a single archive file with multiple members so + 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 tar or zip. GNU tar supports the -z option to invoke gzip transpar- + as tar or zip. GNU tar supports the -z option to invoke gzip transpar- ently. gzip is designed as a complement to tar, not as a replacement. -ENVIRONMENT - The environment variable GZIP can hold a set of default options for - gzip. These options are interpreted first and can be overwritten by +1mENVIRONMENT0m + The environment variable 1mGZIP 22mcan hold a set of default options for + 4mgzip.24m These options are interpreted first and can be overwritten by explicit command line parameters. For example: for sh: GZIP="-8v --name"; export GZIP for csh: setenv GZIP "-8v --name" for MSDOS: set GZIP=-8v --name - On Vax/VMS, the name of the environment variable is GZIP_OPT, to avoid + On Vax/VMS, the name of the environment variable is GZIP_OPT, to avoid a conflict with the symbol set for invocation of the program. -SEE ALSO +1mSEE ALSO0m znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), com- press(1), pack(1), compact(1) - The gzip file format is specified in P. Deutsch, GZIP file format spec- - ification version 4.3, , Inter- - net RFC 1952 (May 1996). The zip deflation format is specified in P. - Deutsch, DEFLATE Compressed Data Format Specification version 1.3, - , Internet RFC 1951 (May 1996). + The 4mgzip24m file format is specified in P. Deutsch, GZIP file format spec- + ification version 4.3, 1m22m, Inter- + net RFC 1952 (May 1996). The 4mzip24m deflation format is specified in P. + Deutsch, DEFLATE Compressed Data Format Specification version 1.3, + 1m22m, Internet RFC 1951 (May 1996). -DIAGNOSTICS +1mDIAGNOSTICS0m Exit status is normally 0; if an error occurs, exit status is 1. If a warning occurs, exit status is 2. Usage: gzip [-cdfhlLnNrtvV19] [-S suffix] [file ...] Invalid options were specified on the command line. - file: not in gzip format - The file specified to gunzip has not been compressed. + 4mfile24m: not in gzip format + The file specified to 4mgunzip24m has not been compressed. - file: Corrupt input. Use zcat to recover some data. + 4mfile24m: Corrupt input. Use zcat to recover some data. The compressed file has been damaged. The data up to the point of failure can be recovered using - zcat file > recover + zcat 4mfile24m > recover - file: compressed with xx bits, can only handle yy bits - File was compressed (using LZW) by a program that could deal - with more bits than the decompress code on this machine. Recom- + 4mfile24m: compressed with 4mxx24m bits, can only handle 4myy24m bits + 4mFile24m was compressed (using LZW) by a program that could deal + with more 4mbits24m than the decompress code on this machine. Recom- press the file with gzip, which compresses better and uses less memory. - file: already has .gz suffix -- no change + 4mfile24m: already has .gz suffix -- no change The file is assumed to be already compressed. Rename the file and try again. - file already exists; do you wish to overwrite (y or n)? + 4mfile24m already exists; do you wish to overwrite (y or n)? Respond "y" if you want the output file to be replaced; "n" if not. @@ -307,66 +307,66 @@ DIAGNOSTICS A SIGSEGV violation was detected which usually means that the input file has been corrupted. - xx.x% Percentage of the input saved by compression. - (Relevant only for -v and -l.) + 4mxx.x%24m Percentage of the input saved by compression. + (Relevant only for 1m-v 22mand 1m-l22m.) -- not a regular file or directory: ignored When the input file is not a regular file or directory, (e.g. a symbolic link, socket, FIFO, device file), it is left unaltered. - -- has xx other links: unchanged - The input file has links; it is left unchanged. See ln(1) for - more information. Use the -f flag to force compression of multi- + -- has 4mxx24m other links: unchanged + The input file has links; it is left unchanged. See 4mln24m(1) for + more information. Use the 1m-f 22mflag to force compression of multi- ply-linked files. -CAVEATS - 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 gunzip for decompression, gunzip - detects that there is extra trailing garbage after the compressed data - and emits a warning by default. You have to use the --quiet option to - suppress the warning. This option can be set in the GZIP environment +1mCAVEATS0m + 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 4mgunzip24m for decompression, 4mgunzip0m + detects that there is extra trailing garbage after the compressed data + and emits a warning by default. You have to use the --quiet option to + suppress the warning. This option can be set in the 1mGZIP 22menvironment variable as in: for sh: GZIP="-q" tar -xfz --block-compress /dev/rst0 for csh: (setenv GZIP -q; tar -xfz --block-compr /dev/rst0 - In the above example, gzip is invoked implicitly by the -z option of - GNU tar. Make sure that the same block size (-b option of tar) is used - for reading and writing compressed data on tapes. (This example + In the above example, gzip is invoked implicitly by the -z option of + GNU tar. Make sure that the same block size (-b option of tar) is used + for reading and writing compressed data on tapes. (This example assumes you are using the GNU version of tar.) -BUGS - The gzip format represents the input size modulo 2^32, so the --list - option reports incorrect uncompressed sizes and compression ratios 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 +1mBUGS0m + The gzip format represents the input size modulo 2^32, so the --list + option reports incorrect uncompressed sizes and compression ratios 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: zcat file.gz | wc -c - The --list option reports sizes as -1 and crc as ffffffff if the com- + The --list option reports sizes as -1 and crc as ffffffff if the com- pressed file is on a non seekable media. - In some rare cases, the --best option gives worse compression than the - default compression level (-6). On some highly redundant files, com- - press compresses better than gzip. + In some rare cases, the --best option gives worse compression than the + default compression level (-6). On some highly redundant files, 4mcom-0m + 4mpress24m compresses better than 4mgzip.0m -COPYRIGHT NOTICE +1mCOPYRIGHT NOTICE0m Copyright (C) 1998, 1999, 2001, 2002 Free Software Foundation, Inc. Copyright (C) 1992, 1993 Jean-loup Gailly - Permission is granted to make and distribute verbatim copies of this - manual provided the copyright notice and this permission notice are + Permission is granted to make and distribute verbatim copies of this + manual provided the copyright notice and this permission notice are preserved on all copies. - Permission is granted to copy and distribute modified versions of this - manual under the conditions for verbatim copying, provided that the - entire resulting derived work is distributed under the terms of a per- + Permission is granted to copy and distribute modified versions of this + manual under the conditions for verbatim copying, provided that the + entire resulting derived work is distributed under the terms of a per- mission notice identical to this one. - Permission is granted to copy and distribute translations of this man- + Permission is granted to copy and distribute translations of this man- ual into another language, under the above conditions for modified ver- - sions, except that this permission notice may be stated in a transla- + sions, except that this permission notice may be stated in a transla- tion approved by the Foundation. local GZIP(1)