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diff --git a/pigz/pigz.1 b/pigz/pigz.1 new file mode 100644 index 000000000..8d75ca228 --- /dev/null +++ b/pigz/pigz.1 @@ -0,0 +1,193 @@ +.TH PIGZ 1 local +.SH NAME +pigz, unpigz \- compress or expand files +.SH SYNOPSIS +.ll +8 +.B pigz +.RB [ " \-cdfhikKlLnNqrRtTz0..9 " ] +[ +.B -b +.I blocksize +] +[ +.B -p +.I threads +] +[ +.B -S +.I suffix +] +[ +.I "name \&..." +] +.ll -8 +.br +.B unpigz +.RB [ " \-cfhikKlLnNqrRtTz " ] +[ +.B -b +.I blocksize +] +[ +.B -p +.I threads +] +[ +.B -S +.I suffix +] +[ +.I "name \&..." +] +.SH DESCRIPTION +.I Pigz +compresses using threads to make use of multiple processors and cores. +The input is broken up into 128 KB chunks with each compressed in parallel. +The individual check value for each chunk is also calculated in parallel. +The compressed data is written in order to the output, and a combined check +value is calculated from the individual check values. +.PP +The compressed data format generated is in the gzip, zlib, or single-entry +zip format using the deflate compression method. The compression produces +partial raw deflate streams which are concatenated by a single write thread +and wrapped with the appropriate header and trailer, where the trailer +contains the combined check value. +.PP +Each partial raw deflate stream is terminated by an empty stored block +(using the Z_SYNC_FLUSH option of zlib), in order to end that partial bit +stream at a byte boundary. That allows the partial streams to be +concatenated simply as sequences of bytes. This adds a very small four to +five byte overhead to the output for each input chunk. +.PP +The default input block size is 128K, but can be changed with the +.B -b +option. The number of compress threads is set by default to the number +of online processors, +which can be changed using the +.B -p +option. Specifying +.B -p 1 +avoids the use of threads entirely. +.PP +The input blocks, while compressed independently, have the last 32K of the +previous block loaded as a preset dictionary to preserve the compression +effectiveness of deflating in a single thread. This can be turned off using +the +.B -i +or +.B --independent +option, so that the blocks can be decompressed +independently for partial error recovery or for random access. +.PP +Decompression can't be parallelized, at least not without specially prepared +deflate streams for that purpose. As a result, +.I pigz +uses a single thread +(the main thread) for decompression, but will create three other threads for +reading, writing, and check calculation, which can speed up decompression +under some circumstances. Parallel decompression can be turned off by +specifying one process +( +.B -dp 1 +or +.B -tp 1 +). +.PP +Compressed files can be restored to their original form using +.I pigz -d +or +.I unpigz. + +.SH OPTIONS +.TP +.B -# --fast --best +Regulate the speed of compression using the specified digit +.IR # , +where +.B \-1 +or +.B \-\-fast +indicates the fastest compression method (less compression) +and +.B \-9 +or +.B \-\-best +indicates the slowest compression method (best compression). +Level 0 is no compression. +.TP +.B -b --blocksize mmm +Set compression block size to mmmK (default 128KiB). +.TP +.B -c --stdout --to-stdout +Write all processed output to stdout (won't delete). +.TP +.B -d --decompress --uncompress +Decompress the compressed input. +.TP +.B -f --force +Force overwrite, compress .gz, links, and to terminal. +.TP +.B -h --help +Display a help screen and quit. +.TP +.B -i --independent +Compress blocks independently for damage recovery. +.TP +.B -k --keep +Do not delete original file after processing. +.TP +.B -K --zip +Compress to PKWare zip (.zip) single entry format. +.TP +.B -l --list +List the contents of the compressed input. +.TP +.B -L --license +Display the +.I pigz +license and quit. +.TP +.B -n --no-name +Do not store or restore file name in/from header. +.TP +.B -N --name +Store/restore file name and mod time in/from header. +.TP +.B -p --processes n +Allow up to n processes (default is the number of online processors) +.TP +.B -q --quiet --silent +Print no messages, even on error. +.TP +.B -r --recursive +Process the contents of all subdirectories. +.TP +.B -R --rsyncable +Input-determined block locations for rsync. +.TP +.B -S --suffix .sss +Use suffix .sss instead of .gz (for compression). +.TP +.B -t --test +Test the integrity of the compressed input. +.TP +.B -T --no-time +Do not store or restore mod time in/from header. +.TP +.B -v --verbose +Provide more verbose output. +.TP +.B -V --version +Show the version of pigz. +.TP +.B -z --zlib +Compress to zlib (.zz) instead of gzip format. +.TP +.B -- +All arguments after "--" are treated as file names (for names that start with "-") +.SH "COPYRIGHT NOTICE" +This software is provided 'as-is', without any express or implied +warranty. In no event will the author be held liable for any damages +arising from the use of this software. +.PP +Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012 Mark Adler <madler@alumni.caltech.edu> |