kc3-lang/brotli/c/tools/brotli.md

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• Hash : 3396c67f
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  Date : 2024-01-15T12:49:21
  

  add brcat alias + flag to decompress concatenated streams
  
  PiperOrigin-RevId: 598652401
  

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• c/tools/brotli.md

• # NAME
  
  brotli(1) -- brotli, brcat, unbrotli - compress or decompress files
  
  # SYNOPSIS
  
  `brotli` [*OPTION|FILE*]...
  
  `brcat` is equivalent to `brotli --decompress --concatenated --stdout`
  
  `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: 24); window size is
      `(pow(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
  * `-C B64`, `--comment=B64`:
      set comment; argument is base64-decoded first;
      when decoding: check stream comment;
      when encoding: embed comment (fingerprint)
  * `-D FILE`, `--dictionary=FILE`:
      use FILE as raw (LZ77) dictionary; same dictionary MUST be used both for
      compression and decompression
  * `-K`, `--concatenated`:
      when decoding, allow concatenated brotli streams as input
  * `-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
  

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