1brotli(1) -- brotli, unbrotli - compress or decompress files 2================================================================ 3 4SYNOPSIS 5-------- 6 7`brotli` [*OPTION|FILE*]... 8 9`unbrotli` is equivalent to `brotli --decompress` 10 11DESCRIPTION 12----------- 13`brotli` is a generic-purpose lossless compression algorithm that compresses 14data using a combination of a modern variant of the **LZ77** algorithm, Huffman 15coding and 2-nd order context modeling, with a compression ratio comparable to 16the best currently available general-purpose compression methods. It is similar 17in speed with deflate but offers more dense compression. 18 19`brotli` command line syntax similar to `gzip (1)` and `zstd (1)`. 20Unlike `gzip (1)`, source files are preserved by default. It is possible to 21remove them after processing by using the `--rm` _option_. 22 23Arguments that look like "`--name`" or "`--name=value`" are _options_. Every 24_option_ has a short form "`-x`" or "`-x value`". Multiple short form _options_ 25could be coalesced: 26 27* "`--decompress --stdout --suffix=.b`" works the same as 28* "`-d -s -S .b`" and 29* "`-dsS .b`" 30 31`brotli` has 3 operation modes: 32 33* default mode is compression; 34* `--decompress` option activates decompression mode; 35* `--test` option switches to integrity test mode; this option is equivalent to 36 "`--decompress --stdout`" except that the decompressed data is discarded 37 instead of being written to standard output. 38 39Every non-option argument is a _file_ entry. If no _files_ are given or _file_ 40is "`-`", `brotli` reads from standard input. All arguments after "`--`" are 41_file_ entries. 42 43Unless `--stdout` or `--output` is specified, _files_ are written to a new file 44whose name is derived from the source _file_ name: 45 46* when compressing, a suffix is appended to the source filename to 47 get the target filename 48* when decompressing, a suffix is removed from the source filename to 49 get the target filename 50 51Default suffix is `.br`, but it could be specified with `--suffix` option. 52 53Conflicting or duplicate _options_ are not allowed. 54 55OPTIONS 56------- 57 58* `-#`: 59 compression level (0-9); bigger values cause denser, but slower compression 60* `-c`, `--stdout`: 61 write on standard output 62* `-d`, `--decompress`: 63 decompress mode 64* `-f`, `--force`: 65 force output file overwrite 66* `-h`, `--help`: 67 display this help and exit 68* `-j`, `--rm`: 69 remove source file(s); `gzip (1)`-like behaviour 70* `-k`, `--keep`: 71 keep source file(s); `zstd (1)`-like behaviour 72* `-n`, `--no-copy-stat`: 73 do not copy source file(s) attributes 74* `-o FILE`, `--output=FILE` 75 output file; valid only if there is a single input entry 76* `-q NUM`, `--quality=NUM`: 77 compression level (0-11); bigger values cause denser, but slower compression 78* `-t`, `--test`: 79 test file integrity mode 80* `-v`, `--verbose`: 81 increase output verbosity 82* `-w NUM`, `--lgwin=NUM`: 83 set LZ77 window size (0, 10-24) (default: 24); window size is 84 `(2**NUM - 16)`; 0 lets compressor decide over the optimal value; bigger 85 windows size improve density; decoder might require up to window size 86 memory to operate 87* `-D FILE`, `--dictionary=FILE`: 88 use FILE as raw (LZ77) dictionary; same dictionary MUST be used both for 89 compression and decompression 90* `-S SUF`, `--suffix=SUF`: 91 output file suffix (default: `.br`) 92* `-V`, `--version`: 93 display version and exit 94* `-Z`, `--best`: 95 use best compression level (default); same as "`-q 11`" 96 97SEE ALSO 98-------- 99 100`brotli` file format is defined in 101[RFC 7932](https://www.ietf.org/rfc/rfc7932.txt). 102 103`brotli` is open-sourced under the 104[MIT License](https://opensource.org/licenses/MIT). 105 106Mailing list: https://groups.google.com/forum/#!forum/brotli 107 108BUGS 109---- 110Report bugs at: https://github.com/google/brotli/issues 111