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author | Yann Collet <cyan@fb.com> | 2016-11-28 11:43:01 (GMT) |
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committer | Yann Collet <cyan@fb.com> | 2016-11-28 11:43:01 (GMT) |
commit | 6b90cfbeab05fb2a74b613352a038330b83da61a (patch) | |
tree | dfb59081dfd56ff75cfe06a98e7de34c8ef8c422 /programs/lz4.1.md | |
parent | 009f06e01d424861048727ab5d9486f7a60a3a6e (diff) | |
download | lz4-6b90cfbeab05fb2a74b613352a038330b83da61a.zip lz4-6b90cfbeab05fb2a74b613352a038330b83da61a.tar.gz lz4-6b90cfbeab05fb2a74b613352a038330b83da61a.tar.bz2 |
Updated man page
Diffstat (limited to 'programs/lz4.1.md')
-rw-r--r-- | programs/lz4.1.md | 68 |
1 files changed, 39 insertions, 29 deletions
diff --git a/programs/lz4.1.md b/programs/lz4.1.md index f10680d..71ad326 100644 --- a/programs/lz4.1.md +++ b/programs/lz4.1.md @@ -32,22 +32,29 @@ The native file format is the `.lz4` format. Differences are : * `lz4` preserves original files - * `lz4` compresses a single file by default (use `-m` for multiple files) + * `lz4` compresses a single file by default (see `-m` for multiple files) * `lz4 file1 file2` means : compress file1 _into_ file2 - * When no destination name is provided, compressed file name receives - a `.lz4` suffix - * When no destination name is provided, if `stdout` is _not_ the console, - it becomes the output (like a silent `-c`). - Therefore `lz4 file > /dev/null` will not create `file.lz4` - * `lz4 file` shows real-time statistics during compression - (use `-q` to silent them) - -Default behaviors can be modified by opt-in commands, described below. -`lz4 -m` more closely follows `gzip` command line syntax, -supporting compression of multiple files into `.lz4`, -the last remaining difference being that source files are preserved by default. -Since it's also possible to erase source file using opt-in command `--rm`, -`lz4 -m --rm` behaves the same as `gzip`. + * `lz4` shows real-time notification statistics + during compression or decompression of a single file + (use `-q` to silent them) + * If no destination name is provided, result is sent to `stdout` + _except if stdout is the console_. + * If no destination name is provided, __and__ if `stdout` is the console, + `file` is compressed into `file.lz4`. + * As a consequence of previous rules, note the following example : + `lz4 file | consumer` sends compressed data to `consumer` through `stdout`, + hence it does _not_ create any `file.lz4`. + +Default behaviors can be modified by opt-in commands, detailed below. + + * `lz4 -m` makes it possible to provide multiple input filenames, + which will be compressed into files using suffix `.lz4`. + Progress notifications are also disabled by default. + This mode has a behavior which more closely mimics `gzip` command line, + with the main difference being that source files are preserved by default. + * It's possible to opt-in to erase source files + on successful compression or decompression, using `--rm` command. + * Consequently, `lz4 -m --rm` behaves the same as `gzip`. ### Concatenation of .lz4 files @@ -131,20 +138,22 @@ only the latest one will be applied. Force write to standard output, even if it is the console. * `-m` `--multiple`: - Multiple file names. - By default, the second filename is used as the destination filename - for the compressed file. - With `-m`, it is possible to specify any number of input filenames. - Each of them will be compressed independently, and the resulting name of - each compressed file will be `filename.lz4`. + Multiple input files. + Compressed file names will be appended a `.lz4` suffix. This mode also reduces notification level. + `lz4 -m` has a behavior equivalent to `gzip -k` + (it preserves source files by default). + +* `-r` : + operate recursively on directories. + This mode also sets `-m` (multiple input files). * `-B#`: Block size \[4-7\](default : 7)<br/> `-B4`= 64KB ; `-B5`= 256KB ; `-B6`= 1MB ; `-B7`= 4MB * `-BD`: - Block dependency (improves compression ratio on small blocks) + Block Dependency (improves compression ratio on small blocks) * `--[no-]frame-crc`: Select frame checksum (default:enabled) @@ -159,8 +168,8 @@ only the latest one will be applied. Sparse mode support (default:enabled on file, disabled on stdout) * `-l`: - Use Legacy format (typically used for Linux Kernel compression)<br/> - Note : `-l` is not compatible with `-m` (`--multiple`) + Use Legacy format (typically for Linux Kernel compression)<br/> + Note : `-l` is not compatible with `-m` (`--multiple`) nor `-r` ### Other options @@ -168,8 +177,8 @@ only the latest one will be applied. Verbose mode * `-q` `--quiet`: - Suppress warnings and real-time statistics; specify twice to suppress - errors too + Suppress warnings and real-time statistics; + specify twice to suppress errors too * `-h` `-H` `--help`: Display help/long help and exit @@ -178,9 +187,10 @@ only the latest one will be applied. Display Version number and exit * `-k` `--keep`: - Don't delete source file. - This is default behavior anyway, so this option is just for compatibility - with `gzip(1)` / `xz(1)`. + Preserve source files (default behavior) + +* `--rm` : + Delete source files on successful compression or decompression ### Benchmark mode |