1.\" $NetBSD: gzip.1,v 1.21 2011/06/19 02:22:36 christos Exp $ 2.\" 3.\" Copyright (c) 1997, 2003, 2004 Matthew R. Green 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 20.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 21.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 22.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 23.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.Dd October 9, 2011 29.Dt GZIP 1 30.Os 31.Sh NAME 32.Nm gzip 33.Nd compression/decompression tool using Lempel-Ziv coding (LZ77) 34.Sh SYNOPSIS 35.Nm 36.Op Fl cdfhkLlNnqrtVv 37.Op Fl S Ar suffix 38.Ar file 39.Oo 40.Ar file Oo ... 41.Oc 42.Oc 43.Nm gunzip 44.Op Fl cfhkLNqrtVv 45.Op Fl S Ar suffix 46.Ar file 47.Oo 48.Ar file Oo ... 49.Oc 50.Oc 51.Nm zcat 52.Op Fl fhV 53.Ar file 54.Oo 55.Ar file Oo ... 56.Oc 57.Oc 58.Sh DESCRIPTION 59The 60.Nm 61program compresses and decompresses files using Lempel-Ziv coding 62(LZ77). 63If no 64.Ar files 65are specified, 66.Nm 67will compress from standard input, or decompress to standard output. 68When in compression mode, each 69.Ar file 70will be replaced with another file with the suffix, set by the 71.Fl S Ar suffix 72option, added, if possible. 73.Pp 74In decompression mode, each 75.Ar file 76will be checked for existence, as will the file with the suffix 77added. 78Each 79.Ar file 80argument must contain a separate complete archive; 81when multiple 82.Ar files 83are indicated, each is decompressed in turn. 84.Pp 85In the case of 86.Nm gzcat 87the resulting data is then concatenated in the manner of 88.Xr cat 1 . 89.Pp 90If invoked as 91.Nm gunzip 92then the 93.Fl d 94option is enabled. 95If invoked as 96.Nm zcat 97or 98.Nm gzcat 99then both the 100.Fl c 101and 102.Fl d 103options are enabled. 104.Pp 105This version of 106.Nm 107is also capable of decompressing files compressed using 108.Xr compress 1 109or 110.Xr bzip2 1 . 111.Sh OPTIONS 112The following options are available: 113.Bl -tag -width XXrXXXrecursiveX 114.It Fl 1 , -fast 115.It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8 116.It Fl 9 , -best 117These options change the compression level used, with the 118.Fl 1 119option being the fastest, with less compression, and the 120.Fl 9 121option being the slowest, with optimal compression. 122The default compression level is 6. 123.It Fl c , -stdout , -to-stdout 124This option specifies that output will go to the standard output 125stream, leaving files intact. 126.It Fl d , -decompress , -uncompress 127This option selects decompression rather than compression. 128.It Fl f , -force 129This option turns on force mode. 130This allows files with multiple links, symbolic links to regular files, 131overwriting of pre-existing files, reading from or writing to a terminal, 132and when combined with the 133.Fl c 134option, allowing non-compressed data to pass through unchanged. 135.It Fl h , -help 136This option prints a usage summary and exits. 137.It Fl k , -keep 138Keep (don't delete) input files during compression 139or decompression. 140.It Fl L , -license 141This option prints 142.Nm 143license. 144.It Fl l , -list 145This option displays information about the file's compressed and 146uncompressed size, ratio, uncompressed name. 147With the 148.Fl v 149option, it also displays the compression method, CRC, date and time 150embedded in the file. 151.It Fl N , -name 152This option causes the stored filename in the input file to be used 153as the output file. 154.It Fl n , -no-name 155This option stops the filename and timestamp from being stored in 156the output file. 157.It Fl q , -quiet 158With this option, no warnings or errors are printed. 159.It Fl r , -recursive 160This option is used to 161.Nm 162the files in a directory tree individually, using the 163.Xr fts 3 164library. 165.It Fl S Ar suffix , Fl -suffix Ar suffix 166This option changes the default suffix from .gz to 167.Ar suffix . 168.It Fl t , -test 169This option will test compressed files for integrity. 170.It Fl V , -version 171This option prints the version of the 172.Nm 173program. 174.It Fl v , -verbose 175This option turns on verbose mode, which prints the compression 176ratio for each file compressed. 177.El 178.Sh ENVIRONMENT 179If the environment variable 180.Ev GZIP 181is set, it is parsed as a white-space separated list of options 182handled before any options on the command line. 183Options on the command line will override anything in 184.Ev GZIP . 185.Sh SEE ALSO 186.Xr bzip2 1 , 187.Xr compress 1 , 188.Xr xz 1 , 189.Xr fts 3 , 190.Xr zlib 3 191.Sh HISTORY 192The 193.Nm 194program was originally written by Jean-loup Gailly, licensed under 195the GNU Public Licence. 196Matthew R. Green wrote a simple front end for 197.Nx 1.3 198distribution media, based on the freely re-distributable zlib library. 199It was enhanced to be mostly feature-compatible with the original 200GNU 201.Nm 202program for 203.Nx 2.0 . 204.Pp 205This implementation of 206.Nm 207was ported based on the 208.Nx 209.Nm , 210and first appeared in 211.Fx 7.0 . 212.Sh AUTHORS 213.An -nosplit 214This implementation of 215.Nm 216was written by 217.An Matthew R. Green Aq mrg@eterna.com.au 218with unpack support written by 219.An Xin LI Aq delphij@FreeBSD.org . 220.Sh BUGS 221According to RFC 1952, the recorded file size is stored in a 32-bit 222integer, therefore, it can not represent files larger than 4GB. 223This limitation also applies to 224.Fl l 225option of 226.Nm 227utility. 228