1.\" $NetBSD: gzip.1,v 1.25 2015/04/06 21:41:17 wiz 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 April 6, 2015 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 , 109.Xr bzip2 1 , 110or 111.Xr xz 1 . 112.Sh OPTIONS 113The following options are available: 114.Bl -tag -width XXrXXXrecursiveX 115.It Fl 1 , -fast 116.It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8 117.It Fl 9 , -best 118These options change the compression level used, with the 119.Fl 1 120option being the fastest, with less compression, and the 121.Fl 9 122option being the slowest, with optimal compression. 123The default compression level is 6. 124.It Fl c , -stdout , -to-stdout 125This option specifies that output will go to the standard output 126stream, leaving files intact. 127.It Fl d , -decompress , -uncompress 128This option selects decompression rather than compression. 129.It Fl f , -force 130This option turns on force mode. 131This allows files with multiple links, symbolic links to regular files, 132overwriting of pre-existing files, reading from or writing to a terminal, 133and when combined with the 134.Fl c 135option, allowing non-compressed data to pass through unchanged. 136.It Fl h , -help 137This option prints a usage summary and exits. 138.It Fl k , -keep 139Keep (don't delete) input files during compression 140or decompression. 141.It Fl L , -license 142This option prints 143.Nm 144license. 145.It Fl l , -list 146This option displays information about the file's compressed and 147uncompressed size, ratio, uncompressed name. 148With the 149.Fl v 150option, it also displays the compression method, CRC, date and time 151embedded in the file. 152.It Fl N , -name 153This option causes the stored filename in the input file to be used 154as the output file. 155.It Fl n , -no-name 156This option stops the filename and timestamp from being stored in 157the output file. 158.It Fl q , -quiet 159With this option, no warnings or errors are printed. 160.It Fl r , -recursive 161This option is used to 162.Nm 163the files in a directory tree individually, using the 164.Xr fts 3 165library. 166.It Fl S Ar suffix , Fl -suffix Ar suffix 167This option changes the default suffix from .gz to 168.Ar suffix . 169.It Fl t , -test 170This option will test compressed files for integrity. 171.It Fl V , -version 172This option prints the version of the 173.Nm 174program. 175.It Fl v , -verbose 176This option turns on verbose mode, which prints the compression 177ratio for each file compressed. 178.El 179.Sh ENVIRONMENT 180If the environment variable 181.Ev GZIP 182is set, it is parsed as a white-space separated list of options 183handled before any options on the command line. 184Options on the command line will override anything in 185.Ev GZIP . 186.Sh SEE ALSO 187.Xr bzip2 1 , 188.Xr compress 1 , 189.Xr xz 1 , 190.Xr fts 3 , 191.Xr zlib 3 192.Sh HISTORY 193The 194.Nm 195program was originally written by Jean-loup Gailly, licensed under 196the GNU Public Licence. 197Matthew R. Green wrote a simple front end for 198.Nx 1.3 199distribution media, based on the freely re-distributable zlib library. 200It was enhanced to be mostly feature-compatible with the original 201GNU 202.Nm 203program for 204.Nx 2.0 . 205.Pp 206This implementation of 207.Nm 208was ported based on the 209.Nx 210.Nm , 211and first appeared in 212.Fx 7.0 . 213.Sh AUTHORS 214.An -nosplit 215This implementation of 216.Nm 217was written by 218.An Matthew R. Green Aq Mt mrg@eterna.com.au 219with unpack support written by 220.An Xin LI Aq Mt delphij@FreeBSD.org . 221.Sh BUGS 222According to RFC 1952, the recorded file size is stored in a 32-bit 223integer, therefore, it can not represent files larger than 4GB. 224This limitation also applies to 225.Fl l 226option of 227.Nm 228utility. 229