1.\" $NetBSD: gzip.1,v 1.20 2009/04/01 08:15:37 mrg 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.Dd July 28, 2009 28.Dt GZIP 1 29.Os 30.Sh NAME 31.Nm gzip 32.Nd compression/decompression tool using Lempel-Ziv coding (LZ77) 33.Sh SYNOPSIS 34.Nm 35.Op Fl cdfhklNnqrtVv 36.Op Fl S Ar suffix 37.Ar file 38.Oo 39.Ar file Oo ... 40.Oc 41.Oc 42.Nm gunzip 43.Op Fl cfhkNqrtVv 44.Op Fl S Ar suffix 45.Ar file 46.Oo 47.Ar file Oo ... 48.Oc 49.Oc 50.Nm zcat 51.Op Fl fhV 52.Ar file 53.Oo 54.Ar file Oo ... 55.Oc 56.Oc 57.Sh DESCRIPTION 58The 59.Nm 60program compresses and decompresses files using Lempel-Ziv coding 61(LZ77). 62If no 63.Ar files 64are specified, 65.Nm 66will compress from standard input, or decompress to standard output. 67When in compression mode, each 68.Ar file 69will be replaced with another file with the suffix, set by the 70.Fl S Ar suffix 71option, added, if possible. 72In decompression mode, each 73.Ar file 74will be checked for existence, as will the file with the suffix 75added. 76.Pp 77If invoked as 78.Nm gunzip 79then the 80.Fl d 81option is enabled. 82If invoked as 83.Nm zcat 84or 85.Nm gzcat 86then both the 87.Fl c 88and 89.Fl d 90options are enabled. 91.Pp 92This version of 93.Nm 94is also capable of decompressing files compressed using 95.Xr pack 1 , 96.Xr compress 1 97or 98.Xr bzip2 1 . 99.Sh OPTIONS 100The following options are available: 101.Bl -tag -width XXrXXXrecursiveX 102.It Fl 1 , -fast 103.It Fl 2 104.It Fl 3 105.It Fl 4 106.It Fl 5 107.It Fl 6 108.It Fl 7 109.It Fl 8 110.It Fl 9 , -best 111These options change the compression level used, with the 112.Fl 1 113option being the fastest, with less compression, and the 114.Fl 9 115option being the slowest, with optimal compression. 116The default compression level is 6. 117.It Fl c , -stdout , -to-stdout 118This option specifies that output will go to the standard output 119stream, leaving files intact. 120.It Fl d , -decompress , -uncompress 121This option selects decompression rather than compression. 122.It Fl f , -force 123This option turns on force mode. 124This allows files with multiple links, overwriting of pre-existing 125files, reading from or writing to a terminal, and when combined 126with the 127.Fl c 128option, allowing non-compressed data to pass through unchanged. 129.It Fl h , -help 130This option prints a usage summary and exits. 131.It Fl k , -keep 132Keep (don't delete) input files during compression 133or decompression. 134.It Fl l , -list 135This option displays information about the file's compressed and 136uncompressed size, ratio, uncompressed name. 137With the 138.Fl v 139option, it also displays the compression method, CRC, date and time 140embedded in the file. 141.It Fl N , -name 142This option causes the stored filename in the input file to be used 143as the output file. 144.It Fl n , -no-name 145This option stops the filename and timestamp from being stored in 146the output file. 147.It Fl q , -quiet 148With this option, no warnings or errors are printed. 149.It Fl r , -recursive 150This option is used to 151.Nm 152the files in a directory tree individually, using the 153.Xr fts 3 154library. 155.It Fl S Ar suffix , Fl -suffix Ar suffix 156This option changes the default suffix from .gz to 157.Ar suffix . 158.It Fl t , -test 159This option will test compressed files for integrity. 160.It Fl V , -version 161This option prints the version of the 162.Nm 163program. 164.It Fl v , -verbose 165This option turns on verbose mode, which prints the compression 166ratio for each file compressed. 167.El 168.Sh ENVIRONMENT 169If the environment variable 170.Ev GZIP 171is set, it is parsed as a white-space separated list of options 172handled before any options on the command line. 173Options on the command line will override anything in 174.Ev GZIP . 175.Sh SEE ALSO 176.Xr bzip2 1 , 177.Xr compress 1 , 178.Xr fts 3 , 179.Xr zlib 3 180.Sh HISTORY 181The 182.Nm 183program was originally written by Jean-loup Gailly, licensed under 184the GNU Public Licence. 185Matthew R. Green wrote a simple front end for 186.Nx 1.3 187distribution media, based on the freely re-distributable zlib library. 188It was enhanced to be mostly feature-compatible with the original 189GNU 190.Nm 191program for 192.Nx 2.0 . 193.Pp 194This manual documents 195.Nx 196.Nm 197version 20040427. 198.Sh AUTHORS 199This implementation of 200.Nm 201was written by 202.An Matthew R. Green Aq Mt mrg@eterna.com.au . 203