228 lines
5.8 KiB
Groff
228 lines
5.8 KiB
Groff
.\" $NetBSD: gzip.1,v 1.21 2011/06/19 02:22:36 christos Exp $
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.\"
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.\" Copyright (c) 1997, 2003, 2004 Matthew R. Green
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.Dd October 9, 2011
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.Dt GZIP 1
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.Os
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.Sh NAME
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.Nm gzip
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.Nd compression/decompression tool using Lempel-Ziv coding (LZ77)
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.Sh SYNOPSIS
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.Nm
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.Op Fl cdfhkLlNnqrtVv
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.Op Fl S Ar suffix
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.Ar file
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.Oo
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.Ar file Oo ...
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.Oc
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.Oc
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.Nm gunzip
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.Op Fl cfhkLNqrtVv
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.Op Fl S Ar suffix
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.Ar file
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.Oo
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.Ar file Oo ...
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.Oc
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.Oc
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.Nm zcat
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.Op Fl fhV
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.Ar file
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.Oo
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.Ar file Oo ...
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.Oc
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.Oc
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.Sh DESCRIPTION
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The
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.Nm
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program compresses and decompresses files using Lempel-Ziv coding
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(LZ77).
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If no
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.Ar files
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are specified,
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.Nm
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will compress from standard input, or decompress to standard output.
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When in compression mode, each
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.Ar file
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will be replaced with another file with the suffix, set by the
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.Fl S Ar suffix
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option, added, if possible.
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.Pp
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In decompression mode, each
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.Ar file
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will be checked for existence, as will the file with the suffix
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added.
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Each
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.Ar file
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argument must contain a separate complete archive;
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when multiple
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.Ar files
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are indicated, each is decompressed in turn.
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.Pp
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In the case of
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.Nm gzcat
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the resulting data is then concatenated in the manner of
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.Xr cat 1 .
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.Pp
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If invoked as
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.Nm gunzip
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then the
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.Fl d
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option is enabled.
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If invoked as
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.Nm zcat
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or
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.Nm gzcat
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then both the
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.Fl c
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and
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.Fl d
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options are enabled.
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.Pp
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This version of
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.Nm
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is also capable of decompressing files compressed using
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.Xr compress 1
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or
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.Xr bzip2 1 .
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.Sh OPTIONS
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The following options are available:
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.Bl -tag -width XXrXXXrecursiveX
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.It Fl 1 , -fast
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.It Fl 2 , 3 , 4 , 5 , 6 , 7 , 8
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.It Fl 9 , -best
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These options change the compression level used, with the
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.Fl 1
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option being the fastest, with less compression, and the
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.Fl 9
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option being the slowest, with optimal compression.
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The default compression level is 6.
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.It Fl c , -stdout , -to-stdout
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This option specifies that output will go to the standard output
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stream, leaving files intact.
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.It Fl d , -decompress , -uncompress
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This option selects decompression rather than compression.
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.It Fl f , -force
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This option turns on force mode.
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This allows files with multiple links, symbolic links to regular files,
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overwriting of pre-existing files, reading from or writing to a terminal,
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and when combined with the
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.Fl c
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option, allowing non-compressed data to pass through unchanged.
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.It Fl h , -help
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This option prints a usage summary and exits.
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.It Fl k , -keep
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Keep (don't delete) input files during compression
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or decompression.
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.It Fl L , -license
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This option prints
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.Nm
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license.
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.It Fl l , -list
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This option displays information about the file's compressed and
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uncompressed size, ratio, uncompressed name.
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With the
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.Fl v
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option, it also displays the compression method, CRC, date and time
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embedded in the file.
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.It Fl N , -name
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This option causes the stored filename in the input file to be used
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as the output file.
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.It Fl n , -no-name
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This option stops the filename and timestamp from being stored in
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the output file.
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.It Fl q , -quiet
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With this option, no warnings or errors are printed.
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.It Fl r , -recursive
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This option is used to
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.Nm
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the files in a directory tree individually, using the
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.Xr fts 3
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library.
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.It Fl S Ar suffix , Fl -suffix Ar suffix
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This option changes the default suffix from .gz to
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.Ar suffix .
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.It Fl t , -test
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This option will test compressed files for integrity.
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.It Fl V , -version
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This option prints the version of the
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.Nm
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program.
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.It Fl v , -verbose
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This option turns on verbose mode, which prints the compression
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ratio for each file compressed.
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.El
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.Sh ENVIRONMENT
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If the environment variable
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.Ev GZIP
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is set, it is parsed as a white-space separated list of options
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handled before any options on the command line.
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Options on the command line will override anything in
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.Ev GZIP .
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.Sh SEE ALSO
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.Xr bzip2 1 ,
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.Xr compress 1 ,
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.Xr xz 1 ,
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.Xr fts 3 ,
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.Xr zlib 3
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.Sh HISTORY
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The
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.Nm
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program was originally written by Jean-loup Gailly, licensed under
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the GNU Public Licence.
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Matthew R. Green wrote a simple front end for
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.Nx 1.3
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distribution media, based on the freely re-distributable zlib library.
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It was enhanced to be mostly feature-compatible with the original
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GNU
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.Nm
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program for
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.Nx 2.0 .
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.Pp
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This implementation of
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.Nm
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was ported based on the
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.Nx
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.Nm ,
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and first appeared in
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.Fx 7.0 .
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.Sh AUTHORS
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.An -nosplit
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This implementation of
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.Nm
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was written by
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.An Matthew R. Green Aq mrg@eterna.com.au
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with unpack support written by
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.An Xin LI Aq delphij@FreeBSD.org .
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.Sh BUGS
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According to RFC 1952, the recorded file size is stored in a 32-bit
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integer, therefore, it can not represent files larger than 4GB.
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This limitation also applies to
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.Fl l
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option of
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.Nm
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utility.
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