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brotli

Section: User Manual (1)
Updated: August 14 2021
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NAME

brotli(1)- brotli, brcat, unbrotli- compress or decompress files

SYNOPSIS

B]brotliR] [I]OPTION|FILER]]...

B]brcatR] is equivalent to B]brotli-decompress-concatenated-stdoutR]

B]unbrotliR] is equivalent to B]brotli-decompressR]

DESCRIPTION

B]brotliR] is a generi-purpose lossless compression algorithm that compresses data using a combination of a modern variant of the B]LZ77R] algorithm, Huffman coding and -nd order context modeling, with a compression ratio comparable to the best currently available genera-purpose compression methods. It is similar in speed with deflate but offers more dense compression.

B]brotliR] command line syntax similar to B]gzip (1)R] and B]zstd (1)R]. Unlike B]gzip (1)R], source files are preserved by default. It is possible to remove them after processing by using the B-rmR] I]optionR].

Arguments that look like [lq]B-nameR][rq] or [lq]B-name=valueR][rq] are I]optionsR]. Every I]optionR] has a short form [lq]B-xR][rq] or [lq]B-x valueR][rq]. Multiple short form I]optionsR] could be coalesced:

[bu]: [lq]B-decompress-stdout-suffix=.bR][rq] works the same as
[bu]: [lq]B-d-s-S .bR][rq] and
[bu]: [lq]B-dsS .bR][rq]

B]brotliR] has 3 operation modes:

[bu]: default mode is compression;
[bu]: B-decompressR] option activates decompression mode;
[bu]: B-testR] option switches to integrity test mode; this option is equivalent to [lq]B-decompress-stdoutR][rq] except that the decompressed data is discarded instead of being written to standard output.

Every no-option argument is a I]fileR] entry. If no I]filesR] are given or I]fileR] is [lq]B-R][rq], B]brotliR] reads from standard input. All arguments after [lq]B-R][rq] are I]fileR] entries.

Unless B-stdoutR] or B-outputR] is specified, I]filesR] are written to a new file whose name is derived from the source I]fileR] name:

[bu]: when compressing, a suffix is appended to the source filename to get the target filename
[bu]: when decompressing, a suffix is removed from the source filename to get the target filename

Default suffix is B].brR], but it could be specified with B-suffixR] option.

Conflicting or duplicate I]optionsR] are not allowed.

OPTIONS

[bu]: B-#R]: compression level (-9); bigger values cause denser, but slower compression
[bu]: B-cR], B-stdoutR]: write on standard output
[bu]: B-dR], B-decompressR]: decompress mode
[bu]: B-fR], B-forceR]: force output file overwrite
[bu]: B-hR], B-helpR]: display this help and exit
[bu]: B-jR], B-rmR]: remove source file(s); B]gzip (1)R-like behaviour
[bu]: B-kR], B-keepR]: keep source file(s); B]zstd (1)R-like behaviour
[bu]: B-nR], B-n-cop-statR]: do not copy source file(s) attributes
[bu]: B-o FILER], B-output=FILER] output file; valid only if there is a single input entry
[bu]: B-q NUMR], B-quality=NUMR]: compression level (-11); bigger values cause denser, but slower compression
[bu]: B-tR], B-testR]: test file integrity mode
[bu]: B-vR], B-verboseR]: increase output verbosity
[bu]: B-w NUMR], B-lgwin=NUMR]: set LZ77 window size (0, 1-24) (default: 24); window size is B](pow(2, NUM)- 16)R]; 0 lets compressor decide over the optimal value; bigger windows size improve density; decoder might require up to window size memory to operate
[bu]: B-C B64R], B-comment=B64R]: set comment; argument is base6-decoded first; when decoding: check stream comment; when encoding: embed comment (fingerprint)
[bu]: B-D FILER], B-dictionary=FILER]: use FILE as raw (LZ77) dictionary; same dictionary MUST be used both for compression and decompression
[bu]: B-KR], B-concatenatedR]: when decoding, allow concatenated brotli streams as input
[bu]: B-S SUFR], B-suffix=SUFR]: output file suffix (default: B].brR])
[bu]: B-VR], B-versionR]: display version and exit
[bu]: B-ZR], B-bestR]: use best compression level (default); same as [lq]B-q 11R][rq]

BUGS

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