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diff --git a/modules/brotli/tools/brotli.md b/modules/brotli/tools/brotli.md new file mode 100644 index 0000000000..c029869bce --- /dev/null +++ b/modules/brotli/tools/brotli.md @@ -0,0 +1,107 @@ +brotli(1) -- brotli, unbrotli - compress or decompress files +================================================================ + +SYNOPSIS +-------- + +`brotli` [*OPTION|FILE*]... + +`unbrotli` is equivalent to `brotli --decompress` + +DESCRIPTION +----------- +`brotli` is a generic-purpose lossless compression algorithm that compresses +data using a combination of a modern variant of the **LZ77** algorithm, Huffman +coding and 2-nd order context modeling, with a compression ratio comparable to +the best currently available general-purpose compression methods. It is similar +in speed with deflate but offers more dense compression. + +`brotli` command line syntax similar to `gzip (1)` and `zstd (1)`. +Unlike `gzip (1)`, source files are preserved by default. It is possible to +remove them after processing by using the `--rm` _option_. + +Arguments that look like "`--name`" or "`--name=value`" are _options_. Every +_option_ has a short form "`-x`" or "`-x value`". Multiple short form _options_ +could be coalesced: + +* "`--decompress --stdout --suffix=.b`" works the same as +* "`-d -s -S .b`" and +* "`-dsS .b`" + +`brotli` has 3 operation modes: + +* default mode is compression; +* `--decompress` option activates decompression mode; +* `--test` option switches to integrity test mode; this option is equivalent to + "`--decompress --stdout`" except that the decompressed data is discarded + instead of being written to standard output. + +Every non-option argument is a _file_ entry. If no _files_ are given or _file_ +is "`-`", `brotli` reads from standard input. All arguments after "`--`" are +_file_ entries. + +Unless `--stdout` or `--output` is specified, _files_ are written to a new file +whose name is derived from the source _file_ name: + +* when compressing, a suffix is appended to the source filename to + get the target filename +* when decompressing, a suffix is removed from the source filename to + get the target filename + +Default suffix is `.br`, but it could be specified with `--suffix` option. + +Conflicting or duplicate _options_ are not allowed. + +OPTIONS +------- + +* `-#`: + compression level (0-9); bigger values cause denser, but slower compression +* `-c`, `--stdout`: + write on standard output +* `-d`, `--decompress`: + decompress mode +* `-f`, `--force`: + force output file overwrite +* `-h`, `--help`: + display this help and exit +* `-j`, `--rm`: + remove source file(s); `gzip (1)`-like behaviour +* `-k`, `--keep`: + keep source file(s); `zstd (1)`-like behaviour +* `-n`, `--no-copy-stat`: + do not copy source file(s) attributes +* `-o FILE`, `--output=FILE` + output file; valid only if there is a single input entry +* `-q NUM`, `--quality=NUM`: + compression level (0-11); bigger values cause denser, but slower compression +* `-t`, `--test`: + test file integrity mode +* `-v`, `--verbose`: + increase output verbosity +* `-w NUM`, `--lgwin=NUM`: + set LZ77 window size (0, 10-24) (default: 22); window size is + `(2**NUM - 16)`; 0 lets compressor decide over the optimal value; bigger + windows size improve density; decoder might require up to window size + memory to operate +* `-S SUF`, `--suffix=SUF`: + output file suffix (default: `.br`) +* `-V`, `--version`: + display version and exit +* `-Z`, `--best`: + use best compression level (default); same as "`-q 11`" + +SEE ALSO +-------- + +`brotli` file format is defined in +[RFC 7932](https://www.ietf.org/rfc/rfc7932.txt). + +`brotli` is open-sourced under the +[MIT License](https://opensource.org/licenses/MIT). + +Mailing list: https://groups.google.com/forum/#!forum/brotli + +BUGS +---- +Report bugs at: https://github.com/google/brotli/issues |