X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=gzip.1;h=9b221a78cb225161947916cf8744a012037df01e;hb=007e2027ba15d7e77477b7eac974a257be59f0b2;hp=8960b877012b9716f2a47f8cf6aec7ea647345a6;hpb=15eea35eec74f226bb721ebf0b3ee7473b1a5ff9;p=debian%2Fgzip diff --git a/gzip.1 b/gzip.1 index 8960b87..9b221a7 100644 --- a/gzip.1 +++ b/gzip.1 @@ -4,7 +4,8 @@ gzip, gunzip, zcat \- compress or expand files .SH SYNOPSIS .ll +8 .B gzip -.RB [ " \-acdfhlLnNrtvV19 " ] +.RB [ " \-acdfhklLnNrtvV19 " ] +.RB [ --rsyncable ] .RB [ \-S\ suffix ] [ .I "name \&..." @@ -12,7 +13,7 @@ gzip, gunzip, zcat \- compress or expand files .ll -8 .br .B gunzip -.RB [ " \-acfhlLnNrtvV " ] +.RB [ " \-acfhklLnNrtvV " ] .RB [ \-S\ suffix ] [ .I "name \&..." @@ -28,7 +29,7 @@ gzip, gunzip, zcat \- compress or expand files reduces the size of the named files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension -.B "\&.gz," +.BR "\&.gz" , while keeping the same ownership modes, access and modification times. (The default extension is .B "\-gz" @@ -65,14 +66,14 @@ Compressed files can be restored to their original form using or .I gunzip or -.I zcat. +.IR 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. .PP .I gunzip takes a list of files on its command line and replaces each -file whose name ends with .gz, -gz, .z, -z, _z or .Z +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. .I gunzip @@ -95,14 +96,19 @@ extension. .PP .I gunzip can currently decompress files created by -.I gzip, zip, compress, compress -H +.IR gzip , +.IR zip , +.IR compress , +.I "compress -H" or -.I pack. +.IR pack . The detection of the input format is automatic. When using the first two formats, .I gunzip checks a 32 bit CRC. For -.I pack, gunzip +.I pack +and +.I gunzip checks the uncompressed length. The standard .I compress format was not designed to allow consistency checks. However @@ -131,18 +137,18 @@ To extract zip files with several members, use .I unzip instead of -.I gunzip. +.IR gunzip . .PP .I zcat is identical to .I gunzip -.B \-c. +.BR \-c . (On some systems, .I zcat may be installed as .I gzcat to preserve the original link to -.I compress.) +.IR compress .) .I zcat uncompresses either a list of files on the command line or its standard input and writes the uncompressed data on standard output. @@ -176,17 +182,6 @@ number of used disk blocks almost never increases. .I gzip preserves the mode, ownership and timestamps of files when compressing or decompressing. -.PP -The -.I gzip -file format is specified in P. Deutsch, \s-1GZIP\s0 file format -specification version 4.3, , -Internet RFC 1952 (May 1996). The -.I zip -deflation format is specified in P. Deutsch, \s-1DEFLATE\s0 Compressed -Data Format Specification version 1.3, -, Internet RFC 1951 (May 1996). - .SH OPTIONS .TP .B \-a --ascii @@ -208,12 +203,12 @@ 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 -.I gzip, +.IR gzip , and if the option --stdout is also given, copy the input data without change -to the standard ouput: let +to the standard output: let .I zcat behave as -.I cat. +.IR cat . If .B \-f is not given, @@ -224,6 +219,9 @@ prompts to verify whether an existing file should be overwritten. .B \-h --help Display a help screen and quit. .TP +.B \-k --keep +Keep (don't delete) input files during compression or decompression. +.TP .B \-l --list For each compressed file, list the following fields: @@ -294,22 +292,20 @@ will descend into the directory and compress all the files it finds there While compressing, synchronize the output occasionally based on the input. This increases size by less than 1 percent most cases, but means that the .BR rsync (1) -program can much more efficiently synchronize files compressed with this flag. +program can take advantage of similarities in the uncompressed input +when synchronizing two files compressed with this flag. .I gunzip cannot tell the difference between a compressed file created with this option, and one created without it. .TP .B \-S .suf --suffix .suf -Use suffix .suf instead of .gz. Any suffix can be given, but suffixes +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. A null suffix forces gunzip to try -decompression on all given files regardless of suffix, as in: - - gunzip -S "" * (*.* for MSDOS) +are transferred to other systems. -Previous versions of gzip used -the .z suffix. This was changed to avoid a conflict with -.IR pack "(1)". +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. .TP .B \-t --test Test. Check the compressed file integrity. @@ -382,7 +378,7 @@ replacement. The environment variable .B GZIP can hold a set of default options for -.I gzip. +.IR gzip . These options are interpreted first and can be overwritten by explicit command line parameters. For example: for sh: GZIP="-8v --name"; export GZIP @@ -392,26 +388,25 @@ explicit command line parameters. For example: 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. .SH "SEE ALSO" -znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), compress(1), -pack(1), compact(1) +znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), compress(1) .PP The .I gzip file format is specified in P. Deutsch, \s-1GZIP\s0 file format specification version 4.3, -.BR , +.BR , Internet RFC 1952 (May 1996). The .I zip deflation format is specified in P. Deutsch, \s-1DEFLATE\s0 Compressed Data Format Specification version 1.3, -.BR , +.BR , Internet RFC 1951 (May 1996). .SH "DIAGNOSTICS" Exit status is normally 0; if an error occurs, exit status is 1. If a warning occurs, exit status is 2. .TP -Usage: gzip [-cdfhlLnNrtvV19] [-S suffix] [file ...] +Usage: gzip [-cdfhklLnNrtvV19] [-S suffix] [file ...] Invalid options were specified on the command line. .TP \fIfile\fP\^: not in gzip format @@ -482,7 +477,7 @@ 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.) .SH BUGS -The gzip format represents the the input size modulo 2^32, so the +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 @@ -497,9 +492,9 @@ In some rare cases, the --best option gives worse compression than the default compression level (-6). On some highly redundant files, .I compress compresses better than -.I gzip. +.IR gzip . .SH "COPYRIGHT NOTICE" -Copyright \(co 1998, 1999, 2001, 2002 Free Software Foundation, Inc. +Copyright \(co 1998, 1999, 2001, 2002, 2012 Free Software Foundation, Inc. .br Copyright \(co 1992, 1993 Jean-loup Gailly .PP