1.\" $NetBSD: gzip.1,v 1.18 2005/09/30 13:46:56 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.\" 3. The name of the author may not be used to endorse or promote products 15.\" derived from this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 22.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 24.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.Dd January 26, 2007 31.Dt GZIP 1 32.Os 33.Sh NAME 34.Nm gzip 35.Nd compression/decompression tool using Lempel-Ziv coding (LZ77) 36.Sh SYNOPSIS 37.Nm 38.Op Fl cdfhLlNnqrtVv 39.Op Fl S Ar suffix 40.Ar file 41.Oo 42.Ar file Oo ... 43.Oc 44.Oc 45.Nm gunzip 46.Op Fl cfhLNqrtVv 47.Op Fl S Ar suffix 48.Ar file 49.Oo 50.Ar file Oo ... 51.Oc 52.Oc 53.Nm zcat 54.Op Fl fhV 55.Ar file 56.Oo 57.Ar file Oo ... 58.Oc 59.Oc 60.Sh DESCRIPTION 61The 62.Nm 63program compresses and decompresses files using Lempel-Ziv coding 64(LZ77). 65If no 66.Ar files 67are specified, 68.Nm 69will compress from standard input, or decompress to standard output. 70When in compression mode, each 71.Ar file 72will be replaced with another file with the suffix, set by the 73.Fl S Ar suffix 74option, added, if possible. 75In decompression mode, each 76.Ar file 77will be checked for existence, as will the file with the suffix 78added. 79.Pp 80If invoked as 81.Nm gunzip 82then the 83.Fl d 84option is enabled. 85If invoked as 86.Nm zcat 87or 88.Nm gzcat 89then both the 90.Fl c 91and 92.Fl d 93options are enabled. 94.Pp 95This version of 96.Nm 97is also capable of decompressing files compressed using 98.Xr compress 1 99or 100.Xr bzip2 1 . 101.Sh OPTIONS 102The following options are available: 103.Bl -tag -width XXrXXXrecursiveX 104.It Fl 1 , -fast 105.It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8 106.It Fl 9 , -best 107These options change the compression level used, with the 108.Fl 1 109option being the fastest, with less compression, and the 110.Fl 9 111option being the slowest, with optimal compression. 112The default compression level is 6. 113.It Fl c , -stdout , -to-stdout 114This option specifies that output will go to the standard output 115stream, leaving files intact. 116.It Fl d , -decompress , -uncompress 117This option selects decompression rather than compression. 118.It Fl f , -force 119This option turns on force mode. 120This allows files with multiple links, overwriting of pre-existing 121files, reading from or writing to a terminal, and when combined 122with the 123.Fl c 124option, allowing non-compressed data to pass through unchanged. 125.It Fl h , -help 126This option prints a usage summary and exits. 127.It Fl L , -license 128This option prints 129.Nm 130license. 131.It Fl l , -list 132This option displays information about the file's compressed and 133uncompressed size, ratio, uncompressed name. 134With the 135.Fl v 136option, it also displays the compression method, CRC, date and time 137embedded in the file. 138.It Fl N , -name 139This option causes the stored filename in the input file to be used 140as the output file. 141.It Fl n , -no-name 142This option stops the filename from being stored in the output 143file. 144.It Fl q , -quiet 145With this option, no warnings or errors are printed. 146.It Fl r , -recursive 147This option is used to 148.Nm 149the files in a directory tree individually, using the 150.Xr fts 3 151library. 152.It Fl S Ar suffix , Fl -suffix Ar suffix 153This option changes the default suffix from .gz to 154.Ar suffix . 155.It Fl t , -test 156This option will test compressed files for integrity. 157.It Fl V , -version 158This option prints the version of the 159.Nm 160program. 161.It Fl v , -verbose 162This option turns on verbose mode, which prints the compression 163ratio for each file compressed. 164.El 165.Sh ENVIRONMENT 166If the environment variable 167.Ev GZIP 168is set, it is parsed as a white-space separated list of options 169handled before any options on the command line. 170Options on the command line will override anything in 171.Ev GZIP . 172.Sh SEE ALSO 173.Xr bzip2 1 , 174.Xr compress 1 , 175.Xr fts 3 , 176.Xr zlib 3 177.Sh HISTORY 178The 179.Nm 180program was originally written by Jean-loup Gailly, licensed under 181the GNU Public Licence. 182Matthew R. Green wrote a simple front end for 183.Nx 1.3 184distribution media, based on the freely re-distributable zlib library. 185It was enhanced to be mostly feature-compatible with the original 186GNU 187.Nm 188program for 189.Nx 2.0 . 190.Pp 191This implementation of 192.Nm 193was ported based on the 194.Nx 195.Nm 19620060927, and first appeared in 197.Fx 7.0 . 198.Sh AUTHORS 199This implementation of 200.Nm 201was written by 202.An Matthew R. Green Aq mrg@eterna.com.au . 203