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author | Yann Collet <yann.collet.73@gmail.com> | 2015-03-22 12:42:00 (GMT) |
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committer | Yann Collet <yann.collet.73@gmail.com> | 2015-03-22 12:42:00 (GMT) |
commit | 7cf4e5c94136ee625d7225a72d4c38589a03ec5d (patch) | |
tree | 5775808a82e56f5318d7030bae2d4bf3e41058a2 /programs/lz4.1 | |
parent | f02adc79389732177dca6fa21a3e716249aa63dd (diff) | |
download | lz4-7cf4e5c94136ee625d7225a72d4c38589a03ec5d.zip lz4-7cf4e5c94136ee625d7225a72d4c38589a03ec5d.tar.gz lz4-7cf4e5c94136ee625d7225a72d4c38589a03ec5d.tar.bz2 |
Updates tests & Man pages
Diffstat (limited to 'programs/lz4.1')
-rw-r--r-- | programs/lz4.1 | 197 |
1 files changed, 160 insertions, 37 deletions
diff --git a/programs/lz4.1 b/programs/lz4.1 index 6ae8d3c..8bab7a3 100644 --- a/programs/lz4.1 +++ b/programs/lz4.1 @@ -1,79 +1,202 @@ \" \" lz4.1: This is a manual page for 'lz4' program. This file is part of the \" lz4 <https://code.google.com/p/lz4/> project. +\" Author: Yann Collet \" \" No hyphenation .hy 0 .nr HY 0 -.TH lz4 "1" "2014-02-27" "lz4" "User Commands" +.TH lz4 "1" "2015-03-21" "lz4" "User Commands" .SH NAME -\fBlz4\fR - Extremely fast compression algorithm +\fBlz4, unlz4, lz4cat\fR \- Compress or decompress .lz4 files .SH SYNOPSIS .TP 5 \fBlz4\fR [\fBOPTIONS\fR] [-|INPUT-FILE] <OUTPUT-FILE> +.PP +.B unlz4 +is equivalent to +.BR "lz4 \-d" +.br +.B lz4cat +is equivalent to +.BR "lz4 \-dc" +.br +.PP +When writing scripts that need to decompress files, +it is recommended to always use the name +.B lz4 +with appropriate arguments +.RB ( "lz4 \-d" +or +.BR "lz4 \-dc" ) +instead of the names +.B unlz4 +and +.BR lz4cat . + .SH DESCRIPTION .PP -\fBlz4\fR is an extremely fast lossless compression algorithm. It is based on -the \fBLZ77\fR family of compression scheme. At the compression speed of 400 -MB/s per core, \fBlz4\fR is also scalable with multi-core CPUs. It features -an extremely fast decoder, with speed in multiple GB/s per core, typically -reaching the RAM speed limits on multi-core systems. \fBlz4\fR supports -following options +\fBlz4\fR is an extremely fast lossless compression algorithm, +based on \fBbyte-aligned LZ77\fR family of compression scheme. +\fBlz4\fR offers compression speeds of 400 MB/s per core, linearly scalable with multi-core CPUs. +It features an extremely fast decoder, with speed in multiple GB/s per core, +typically reaching RAM speed limit on multi-core systems. +.B lz4 +supports a command line syntax similar to +.BR gzip (1). +The native file format is the +.B .lz4 +format. + +.SS "Concatenation of .lz4 files" +It is possible to concatenate +.B .lz4 +files as is. +.B lz4 +will decompress such files as if they were a single +.B .lz4 +file. +.PP .SH OPTIONS +. +.SS "Short command concatenation" +In some cases, some options can be expressed using short command +.B "-x" +or long command +.B "--long-word" . +Short commands can be concatenated together. For example, +.B "-d -c" +is equivalent to +.B "-dc" . +Long commands cannot be concatenated. +They must be clearly separated by a space. +. +.SS "Operation mode" +If multiple operation mode options are given, +the last one takes effect. +.TP +.BR \-z ", " \-\-compress +Compress. +This is the default operation mode +when no operation mode option is specified , +no other operation mode is implied from the command name +(for example, +.B unlz4 +implies +.B \-\-decompress ), +nor from the input file name +(for example, a file extension +.B .lz4 +implies +.B \-\-decompress +by default). +.B -z +can also be used to force compression of an already compressed +.B .lz4 +file. +.TP +.BR \-d ", " \-\-decompress ", " \-\-uncompress +Decompress. +.B --decompress +is also the default operation when the input filename has an +.B .lz4 +extensionq +.TP +.BR \-t ", " \-\-test +Test the integrity of compressed +.B .lz4 +files. +The decompressed data is discarded. +No files are created or removed. +. +.SS "Operation modifiers" .TP .B \-1 fast compression (default) .TP .B \-9 high compression + .TP -.B \-d - decompression -.TP -.B \-f - overwrite output without prompting +.BR \-f ", " --force + This option has several effects: +.RS +.IP \(bu 3 +If the target file already exists, +overwrite it without prompting. +.IP \(bu 3 +When used with +.B \-\-decompress +and +.B lz4 +cannot recognize the type of the source file, +copy the source file as is to standard output. +This allows +.B lz4cat +.B \-\-force +to be used like +.BR cat (1) +for files that have not been compressed with +.BR lz4 . +.RE + .TP -.B \-h/\-H - display help/long help and exit +.BR \-c ", " \--stdout ", " \--to-stdout + force write to standard output, even if it is the console + .TP -.B \-V - display Version number and exit +.BR \-m + Multiple file names. + By default, the second filename is used as the output filename for the compressed file. + With +.B -m +, you can specify any number of input filenames, each of them will be compressed +with the resulting compressed file named +.B filename.lz4 +. + .TP -.B \-v - verbose mode +.B \-B# + block size [4-7](default : 7) + B4= 64KB ; B5= 256KB ; B6= 1MB ; B7= 4MB .TP -.B \-q - suppress warnings; specify twice to suppress errors too +.B \-BD + block dependency (improve compression ratio) .TP -.B \-c - force write to standard output, even if it is the console +.B \--no-frame-crc + disable stream checksum (default:enabled) .TP -.B \-t - test compressed file integrity +.B \--frame-content-size + compressed frame includes original size (default:not present) .TP -.B \-z - force compression +.B \--sparse-support + enable sparse file (default:disabled)(experimental) .TP .B \-l use Legacy format (useful for Linux Kernel compression) +. +.SS "Other options" .TP -.B \-B# - block size [4-7](default : 7) - B4= 64KB ; B5= 256KB ; B6= 1MB ; B7= 4MB +.BR \-v ", " --verbose + verbose mode .TP -.B \-BD - block dependency (improve compression ratio) +.BR \-q ", " --quiet + suppress warnings; specify twice to suppress errors too +.TP +.B \-h/\-H + display help/long help and exit .TP -.B \-BX - enable block checksum (default:disabled) +.BR \-V ", " \--version + display Version number and exit .TP -.B \-Sx - disable stream checksum (default:enabled) +.BR \-k ", " \--keep + Don't delete source file. +This is default behavior anyway, so this option is just for compatibility with gzip/xz. .TP .B \-b benchmark file(s) @@ -82,7 +205,7 @@ following options iteration loops [1-9](default : 3), benchmark mode only .SH BUGS -Report bugs at:- https://code.google.com/p/lz4/ +Report bugs at: https://github.com/Cyan4973/lz4 .SH AUTHOR Yann Collet |