1.\" $NetBSD: gzip.1,v 1.16 2004/04/27 02:25:06 mrg Exp $ 2.\" $DragonFly: src/usr.bin/gzip/gzip.1,v 1.1 2004/10/26 11:19:31 joerg Exp $ 3.\" 4.\" Copyright (c) 1997, 2003, 2004 Matthew R. Green 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. The name of the author may not be used to endorse or promote products 16.\" derived from this software without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 24.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.Dd April 27, 2004 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 cdfhlNnqrtVv 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 cfhNqrtVv 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 2 106.It Fl 3 107.It Fl 4 108.It Fl 5 109.It Fl 6 110.It Fl 7 111.It Fl 8 112.It Fl 9 , -best 113These options change the compression level used, with the 114.Fl 1 115option being the fastest, with less compression, and the 116.Fl 9 117option being the slowest, with optimal compression. 118The default compression level is 6. 119.It Fl c , -stdout , -to-stdout 120This option specifies that output will go to the standard output 121stream, leaving files intact. 122.It Fl d , -decompress , -uncompress 123This option selects decompression rather than compression. 124.It Fl f , -force 125This option turns on force mode. 126This allows files with multiple links, overwriting of pre-existing 127files, reading from or writing to a terminal, and when combined 128with the 129.Fl c 130option, allowing non-compressed data to pass through unchanged. 131.It Fl h , -help 132This option prints a usage summary and exits. 133.It Fl l , -list 134This option displays information about the file's compressed and 135uncompressed size, ratio, uncompressed name. 136With the 137.Fl v 138option, it also displays the compression method, CRC, data and time 139embedded in the file. 140.It Fl N , -name 141This option causes the stored filename in the input file to be used 142as the output file. 143.It Fl n , -no-name 144This option stops the filename from being stored in the output 145file. 146.It Fl q , -quiet 147With this option, no warnings or errors are printed. 148.It Fl r , -recursive 149This option is used to 150.Nm 151the files in a directory tree individually, using the 152.Xr fts 3 153library. 154.It Fl S Ar suffix , Fl -suffix Ar suffix 155This option changes the default suffix from .gz to 156.Ar suffix . 157.It Fl t , -test 158This option will test compressed files for integrity. 159.It Fl V , -version 160This option prints the version of the 161.Nm 162program. 163.It Fl v , -verbose 164This option turns on verbose mode, which prints the compression 165ratio for each file compressed. 166.El 167.Sh ENVIRONMENT 168If the environment variable 169.Ev GZIP 170is set, it is parsed as a white-space separated list of options 171handled before any options on the command line. 172Options on the command line will override anything in 173.Ev GZIP . 174.Sh SEE ALSO 175.Xr bzip2 1 , 176.Xr compress 1 , 177.Xr fts 3 , 178.Xr zlib 3 179.Sh HISTORY 180The 181.Nm 182program was originally written by Jean-loup Gailly, licensed under 183the GNU Public Licence. 184Matthew R. Green wrote a simple front end for 185.Nx 1.3 186distribution media, based on the freely re-distributable zlib library. 187It was enhanced to be mostly feature-compatible with the original 188GNU 189.Nm 190program for 191.Nx 2.0 . 192.Pp 193This manual documents 194.Nx 195.Nm 196version 20040427. 197.Sh AUTHORS 198This implementation of 199.Nm 200was written by 201.An Matthew R. Green Aq mrg@eterna.com.au . 202