1.\" $NetBSD: gzip.1,v 1.22 2013/07/20 21:40:00 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.Dd June 18, 2011 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 cdfhlNnqrtVv 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 cfhNqrtVv 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 compress 1 96or 97.Xr bzip2 1 . 98.Sh OPTIONS 99The following options are available: 100.Bl -tag -width XXrXXXrecursiveX 101.It Fl 1 , -fast 102.It Fl 2 103.It Fl 3 104.It Fl 4 105.It Fl 5 106.It Fl 6 107.It Fl 7 108.It Fl 8 109.It Fl 9 , -best 110These options change the compression level used, with the 111.Fl 1 112option being the fastest, with less compression, and the 113.Fl 9 114option being the slowest, with optimal compression. 115The default compression level is 6. 116.It Fl c , -stdout , -to-stdout 117This option specifies that output will go to the standard output 118stream, leaving files intact. 119.It Fl d , -decompress , -uncompress 120This option selects decompression rather than compression. 121.It Fl f , -force 122This option turns on force mode. 123This allows files with multiple links, overwriting of pre-existing 124files, reading from or writing to a terminal, and when combined 125with the 126.Fl c 127option, allowing non-compressed data to pass through unchanged. 128.It Fl h , -help 129This option prints a usage summary and exits. 130.It Fl l , -list 131This option displays information about the file's compressed and 132uncompressed size, ratio, uncompressed name. 133With the 134.Fl v 135option, it also displays the compression method, CRC, date and time 136embedded in the file. 137.It Fl N , -name 138This option causes the stored filename in the input file to be used 139as the output file. 140.It Fl n , -no-name 141This option stops the filename and timestamp from being stored in 142the output file. 143.It Fl q , -quiet 144With this option, no warnings or errors are printed. 145.It Fl r , -recursive 146This option is used to 147.Nm 148the files in a directory tree individually, using the 149.Xr fts 3 150library. 151.It Fl S Ar suffix , Fl -suffix Ar suffix 152This option changes the default suffix from .gz to 153.Ar suffix . 154.It Fl t , -test 155This option will test compressed files for integrity. 156.It Fl V , -version 157This option prints the version of the 158.Nm 159program. 160.It Fl v , -verbose 161This option turns on verbose mode, which prints the compression 162ratio for each file compressed. 163.El 164.Sh ENVIRONMENT 165If the environment variable 166.Ev GZIP 167is set, it is parsed as a white-space separated list of options 168handled before any options on the command line. 169Options on the command line will override anything in 170.Ev GZIP . 171.Sh SEE ALSO 172.Xr bzip2 1 , 173.Xr compress 1 , 174.Xr xz 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 manual documents 192.Nx 193.Nm 194version 20040427. 195.Sh AUTHORS 196This implementation of 197.Nm 198was written by 199.An Matthew R. Green Aq Mt mrg@eterna.com.au . 200