Man1 - brotli.1

brotli - brotli, unbrotli - compress or decompress files

brotli [/OPTION|FILE/]…

unbrotli is equivalent to brotli –decompress

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.

• -#: 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”

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

Report bugs at: https://github.com/google/brotli/issues