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author | alk3pInjection <webmaster@raspii.tech> | 2021-08-30 16:43:38 +0800 |
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committer | alk3pInjection <webmaster@raspii.tech> | 2021-08-30 16:43:38 +0800 |
commit | cbe033a53bfe49d980774e59025e3b2af91778b7 (patch) | |
tree | 558535f91276162e0be70d07b34ed2e6577e38ad /programs/lz4.1 | |
parent | fdd43c66dd9e77283aa8f7e52a881be44d622441 (diff) | |
parent | d44371841a2f1728a3f36839fd4b7e872d0927d3 (diff) |
Merge tag 'v1.9.3' into lineage-18.1HEADlineage-18.1
Change-Id: Iad56c1b17a32f9f356a4c1ff9557f0e79addf481
Diffstat (limited to 'programs/lz4.1')
-rw-r--r-- | programs/lz4.1 | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/programs/lz4.1 b/programs/lz4.1 index f35e29d..d758ed5 100644 --- a/programs/lz4.1 +++ b/programs/lz4.1 @@ -1,5 +1,5 @@ . -.TH "LZ4" "1" "September 2018" "lz4 1.8.3" "User Commands" +.TH "LZ4" "1" "July 2019" "lz4 1.9.2" "User Commands" . .SH "NAME" \fBlz4\fR \- lz4, unlz4, lz4cat \- Compress or decompress \.lz4 files @@ -23,9 +23,6 @@ When writing scripts that need to decompress files, it is recommended to always \fBlz4\fR supports a command line syntax similar \fIbut not identical\fR to \fBgzip(1)\fR\. Differences are : . .IP "\(bu" 4 -\fBlz4\fR preserves original files -. -.IP "\(bu" 4 \fBlz4\fR compresses a single file by default (see \fB\-m\fR for multiple files) . .IP "\(bu" 4 @@ -35,19 +32,16 @@ When writing scripts that need to decompress files, it is recommended to always \fBlz4 file\.lz4\fR will default to decompression (use \fB\-z\fR to force compression) . .IP "\(bu" 4 -\fBlz4\fR shows real\-time notification statistics during compression or decompression of a single file (use \fB\-q\fR to silence them) -. -.IP "\(bu" 4 -If no destination name is provided, result is sent to \fBstdout\fR \fIexcept if stdout is the console\fR\. +\fBlz4\fR preserves original files . .IP "\(bu" 4 -If no destination name is provided, \fBand\fR if \fBstdout\fR is the console, \fBfile\fR is compressed into \fBfile\.lz4\fR\. +\fBlz4\fR shows real\-time notification statistics during compression or decompression of a single file (use \fB\-q\fR to silence them) . .IP "\(bu" 4 -As a consequence of previous rules, note the following example : \fBlz4 file | consumer\fR sends compressed data to \fBconsumer\fR through \fBstdout\fR, hence it does \fInot\fR create \fBfile\.lz4\fR\. +When no destination is specified, result is sent on implicit output, which depends on \fBstdout\fR status\. When \fBstdout\fR \fIis Not the console\fR, it becomes the implicit output\. Otherwise, if \fBstdout\fR is the console, the implicit output is \fBfilename\.lz4\fR\. . .IP "\(bu" 4 -Another consequence of those rules is that to run \fBlz4\fR under \fBnohup\fR, you should provide a destination file: \fBnohup lz4 file file\.lz4\fR, because \fBnohup\fR writes the specified command\'s output to a file\. +It is considered bad practice to rely on implicit output in scripts\. because the script\'s environment may change\. Always use explicit output in scripts\. \fB\-c\fR ensures that output will be \fBstdout\fR\. Conversely, providing a destination name, or using \fB\-m\fR ensures that the output will be either the specified name, or \fBfilename\.lz4\fR respectively\. . .IP "" 0 . @@ -55,7 +49,7 @@ Another consequence of those rules is that to run \fBlz4\fR under \fBnohup\fR, y Default behaviors can be modified by opt\-in commands, detailed below\. . .IP "\(bu" 4 -\fBlz4 \-m\fR makes it possible to provide multiple input filenames, which will be compressed into files using suffix \fB\.lz4\fR\. Progress notifications are also disabled by default (use \fB\-v\fR to enable them)\. This mode has a behavior which more closely mimics \fBgzip\fR command line, with the main remaining difference being that source files are preserved by default\. +\fBlz4 \-m\fR makes it possible to provide multiple input filenames, which will be compressed into files using suffix \fB\.lz4\fR\. Progress notifications become disabled by default (use \fB\-v\fR to enable them)\. This mode has a behavior which more closely mimics \fBgzip\fR command line, with the main remaining difference being that source files are preserved by default\. . .IP "\(bu" 4 Similarly, \fBlz4 \-m \-d\fR can decompress multiple \fB*\.lz4\fR files\. @@ -111,6 +105,10 @@ Test the integrity of compressed \fB\.lz4\fR files\. The decompressed data is di \fB\-b#\fR Benchmark mode, using \fB#\fR compression level\. . +.TP +\fB\-\-list\fR +List information about \.lz4 files\. note : current implementation is limited to single\-frame \.lz4 files\. +. .SS "Operation modifiers" . .TP @@ -118,6 +116,18 @@ Benchmark mode, using \fB#\fR compression level\. Compression level, with # being any value from 1 to 12\. Higher values trade compression speed for compression ratio\. Values above 12 are considered the same as 12\. Recommended values are 1 for fast compression (default), and 9 for high compression\. Speed/compression trade\-off will vary depending on data to compress\. Decompression speed remains fast at all settings\. . .TP +\fB\-\-fast[=#]\fR +Switch to ultra\-fast compression levels\. The higher the value, the faster the compression speed, at the cost of some compression ratio\. If \fB=#\fR is not present, it defaults to \fB1\fR\. This setting overrides compression level if one was set previously\. Similarly, if a compression level is set after \fB\-\-fast\fR, it overrides it\. +. +.TP +\fB\-\-best\fR +Set highest compression level\. Same as -12\. +. +.TP +\fB\-\-favor\-decSpeed\fR +Generate compressed data optimized for decompression speed\. Compressed data will be larger as a consequence (typically by ~0\.5%), while decompression speed will be improved by 5\-20%, depending on use cases\. This option only works in combination with very high compression levels (>=10)\. +. +.TP \fB\-D dictionaryName\fR Compress, decompress or benchmark using dictionary \fIdictionaryName\fR\. Compression and decompression must use the same dictionary to be compatible\. Using a different dictionary during decompression will either abort due to decompression error, or generate a checksum error\. . @@ -137,7 +147,7 @@ Force write to standard output, even if it is the console\. . .TP \fB\-m\fR \fB\-\-multiple\fR -Multiple input files\. Compressed file names will be appended a \fB\.lz4\fR suffix\. This mode also reduces notification level\. \fBlz4 \-m\fR has a behavior equivalent to \fBgzip \-k\fR (it preserves source files by default)\. +Multiple input files\. Compressed file names will be appended a \fB\.lz4\fR suffix\. This mode also reduces notification level\. Can also be used to list multiple files\. \fBlz4 \-m\fR has a behavior equivalent to \fBgzip \-k\fR (it preserves source files by default)\. . .TP \fB\-r\fR @@ -151,12 +161,12 @@ Block size [4\-7](default : 7) \fB\-B4\fR= 64KB ; \fB\-B5\fR= 256KB ; \fB\-B6\fR= 1MB ; \fB\-B7\fR= 4MB . .TP -\fB\-BD\fR -Block Dependency (improves compression ratio on small blocks) +\fB\-BI\fR +Produce independent blocks (default) . .TP -\fB\-\-fast[=#]\fR -switch to ultra\-fast compression levels\. If \fB=#\fR is not present, it defaults to \fB1\fR\. The higher the value, the faster the compression speed, at the cost of some compression ratio\. This setting overwrites compression level if one was set previously\. Similarly, if a compression level is set after \fB\-\-fast\fR, it overrides it\. +\fB\-BD\fR +Blocks depend on predecessors (improves compression ratio, more noticeable on small blocks) . .TP \fB\-\-[no\-]frame\-crc\fR |