1 brotli(1) -- brotli, unbrotli - compress or decompress files 2 ================================================================ 3 4 SYNOPSIS 5 -------- 6 7 `brotli` [*OPTION|FILE*]... 8 9 `unbrotli` is equivalent to `brotli --decompress` 10 11 DESCRIPTION 12 ----------- 13 `brotli` is a generic-purpose lossless compression algorithm that compresses 14 data using a combination of a modern variant of the **LZ77** algorithm, Huffman 15 coding and 2-nd order context modeling, with a compression ratio comparable to 16 the best currently available general-purpose compression methods. It is similar 17 in speed with deflate but offers more dense compression. 18 19 `brotli` command line syntax similar to `gzip (1)` and `zstd (1)`. 20 Unlike `gzip (1)`, source files are preserved by default. It is possible to 21 remove them after processing by using the `--rm` _option_. 22 23 Arguments that look like "`--name`" or "`--name=value`" are _options_. Every 24 _option_ has a short form "`-x`" or "`-x value`". Multiple short form _options_ 25 could 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 39 Every non-option argument is a _file_ entry. If no _files_ are given or _file_ 40 is "`-`", `brotli` reads from standard input. All arguments after "`--`" are 41 _file_ entries. 42 43 Unless `--stdout` or `--output` is specified, _files_ are written to a new file 44 whose 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 51 Default suffix is `.br`, but it could be specified with `--suffix` option. 52 53 Conflicting or duplicate _options_ are not allowed. 54 55 OPTIONS 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: 22); 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 * `-S SUF`, `--suffix=SUF`: 88 output file suffix (default: `.br`) 89 * `-V`, `--version`: 90 display version and exit 91 * `-Z`, `--best`: 92 use best compression level (default); same as "`-q 11`" 93 94 SEE ALSO 95 -------- 96 97 `brotli` file format is defined in 98 [RFC 7932](https://www.ietf.org/rfc/rfc7932.txt). 99 100 `brotli` is open-sourced under the 101 [MIT License](https://opensource.org/licenses/MIT). 102 103 Mailing list: https://groups.google.com/forum/#!forum/brotli 104 105 BUGS 106 ---- 107 Report bugs at: https://github.com/google/brotli/issues 108
