LZ4(1)                Cosmopolitan User Commands               -*-text-*-

ðððð
       ð¹ðð° - lz4, unlz4, lz4cat - Compress or decompress .lz4 files

ðððððððð
       ð¹ðð° [OÌ²PÌ²TÌ²IÌ²OÌ²NÌ²SÌ²] [-|INPUT-FILE] OÌ²UÌ²TÌ²PÌ²UÌ²TÌ²-Ì²FÌ²IÌ²LÌ²EÌ²

       ðð»ð¹ðð° is equivalent to ð¹ðð° -ð±

       ð¹ðð°ð°ð®ð is equivalent to ð¹ðð° -ð±ð°ð³ðº

       When  writing scripts that need to decompress files, it is recomâ
       mended to always use the name ð¹ðð° with appropriate arguments (ð¹ðð°
       -ð± or ð¹ðð° -ð±ð°) instead of the names ðð»ð¹ðð° and ð¹ðð°ð°ð®ð.

ððððððððððð
       ð¹ðð° is an extremely fast lossless compression algorithm, based on
       ð¯ððð²-ð®ð¹ð¶ð´ð»ð²ð± ððð³ð³ family of compression scheme. ð¹ðð°  offers  comâ
       pression  speeds  of  400  MB/s  per core, linearly scalable with
       multi-core CPUs. It features  an  extremely  fast  decoder,  with
       speed  in  multiple  GB/s  per core, typically reaching RAM speed
       limit on multi-core systems. The native file format is  the  .ð¹ðð°
       format.

   ðð¶ð³ð³ð²ð¿ð²ð»ð°ð² ð¯ð²ððð²ð²ð» ð¹ðð° ð®ð»ð± ð´ðð¶ð½
       ð¹ðð°  supports  a command line syntax similar bÌ²uÌ²tÌ² nÌ²oÌ²tÌ² iÌ²dÌ²eÌ²nÌ²tÌ²iÌ²cÌ²aÌ²lÌ² to
       ð´ðð¶ð½(ð­). Differences are :

       Â·   ð¹ðð° preserves original files

       Â·   ð¹ðð° compresses a single file by default (see -ðº for  multiple
           files)

       Â·   ð¹ðð° ð³ð¶ð¹ð²ð­ ð³ð¶ð¹ð²ð® means : compress file1 iÌ²nÌ²tÌ²oÌ² file2

       Â·   ð¹ðð°  ð³ð¶ð¹ð².ð¹ðð°  will default to decompression (use -ð to force
           compression)

       Â·   ð¹ðð° shows real-time notification statistics  during  compresâ
           sion  or  decompression  of  a single file (use -ð¾ to silence
           them)

       Â·   If no destination name is provided, result is sent to  ððð±ð¼ðð
           eÌ²xÌ²cÌ²eÌ²pÌ²tÌ² iÌ²fÌ² sÌ²tÌ²dÌ²oÌ²uÌ²tÌ² iÌ²sÌ² tÌ²hÌ²eÌ² cÌ²oÌ²nÌ²sÌ²oÌ²lÌ²eÌ².

       Â·   If no destination name is provided, ð®ð»ð± if ððð±ð¼ðð is the conâ
           sole, ð³ð¶ð¹ð² is compressed into ð³ð¶ð¹ð².ð¹ðð°.

       Â·   As a consequence of previous rules, note the following  examâ
           ple  :  ð¹ðð° ð³ð¶ð¹ð² | ð°ð¼ð»ðððºð²ð¿ sends compressed data to ð°ð¼ð»ðððºð²ð¿
           through ððð±ð¼ðð, hence it does nÌ²oÌ²tÌ² create ð³ð¶ð¹ð².ð¹ðð°.

       Â·   Another consequence of those rules is that to run  ð¹ðð°  under
           ð»ð¼ðµðð½,  you should provide a destination file: ð»ð¼ðµðð½ ð¹ðð° ð³ð¶ð¹ð²
           ð³ð¶ð¹ð².ð¹ðð°, because ð»ð¼ðµðð½ writes the specified commandÂ´s output
           to a file.



       Default  behaviors  can  be modified by opt-in commands, detailed
       below.

       Â·   ð¹ðð° -ðº makes it possible to provide multiple input filenames,
           which  will  be  compressed  into  files  using  suffix .ð¹ðð°.
           Progress notifications are also disabled by default  (use  -ð
           to  enable them). This mode has a behavior which more closely
           mimics ð´ðð¶ð½ command line, with the main remaining  difference
           being that source files are preserved by default.

       Â·   Similarly, ð¹ðð° -ðº -ð± can decompress multiple *.ð¹ðð° files.

       Â·   ItÂ´s  possible  to opt-in to erase source files on successful
           compression or decompression, using --ð¿ðº command.

       Â·   Consequently, ð¹ðð° -ðº --ð¿ðº behaves the same as ð´ðð¶ð½.



   ðð¼ð»ð°ð®ðð²ð»ð®ðð¶ð¼ð» ð¼ð³ .ð¹ðð° ð³ð¶ð¹ð²ð
       It is possible to concatenate .ð¹ðð° files as is. ð¹ðð°  will  decomâ
       press such files as if they were a single .ð¹ðð° file. For example:



           lz4 file1  > foo.lz4
           lz4 file2 >> foo.lz4



       Then ð¹ðð°ð°ð®ð ð³ð¼ð¼.ð¹ðð° is equivalent to ð°ð®ð ð³ð¶ð¹ð²ð­ ð³ð¶ð¹ð²ð®.

ððððððð
   ððµð¼ð¿ð ð°ð¼ðºðºð®ð»ð±ð ð°ð¼ð»ð°ð®ðð²ð»ð®ðð¶ð¼ð»
       In  some cases, some options can be expressed using short command
       -ð or long command --ð¹ð¼ð»ð´-ðð¼ð¿ð±. Short commands  can  be  concateâ
       nated  together.  For  example,  -ð± -ð° is equivalent to -ð±ð°. Long
       commands cannot be concatenated. They must be  clearly  separated
       by a space.

   ððð¹ðð¶ð½ð¹ð² ð°ð¼ðºðºð®ð»ð±ð
       When multiple contradictory commands are issued on a same command
       line, only the latest one will be applied.

   ðð½ð²ð¿ð®ðð¶ð¼ð» ðºð¼ð±ð²
       -ð --ð°ð¼ðºð½ð¿ð²ðð
              Compress. This is the default operation mode when no operâ
              ation mode option is specified, no other operation mode is
              implied from the command name (for example, ðð»ð¹ðð°  implies
              --ð±ð²ð°ð¼ðºð½ð¿ð²ðð),  nor from the input file name (for example,
              a file extension .ð¹ðð° implies --ð±ð²ð°ð¼ðºð½ð¿ð²ðð by default). -ð
              can  also  be used to force compression of an already comâ
              pressed .ð¹ðð° file.

       -ð± --ð±ð²ð°ð¼ðºð½ð¿ð²ðð --ðð»ð°ð¼ðºð½ð¿ð²ðð
              Decompress. --ð±ð²ð°ð¼ðºð½ð¿ð²ðð is  also  the  default  operation
              when the input filename has an .ð¹ðð° extension.

       -ð --ðð²ðð
              Test  the  integrity  of compressed .ð¹ðð° files. The decomâ
              pressed data  is  discarded.  No  files  are  created  nor
              removed.

       -ð¯#    Benchmark mode, using # compression level.

   ðð½ð²ð¿ð®ðð¶ð¼ð» ðºð¼ð±ð¶ð³ð¶ð²ð¿ð
       -#     Compression  level,  with  # being any value from 1 to 12.
              Higher values  trade  compression  speed  for  compression
              ratio. Values above 12 are considered the same as 12. Recâ
              ommended values are 1 for fast compression (default),  and
              9  for  high compression. Speed/compression trade-off will
              vary depending on data to  compress.  Decompression  speed
              remains fast at all settings.

       -ð ð±ð¶ð°ðð¶ð¼ð»ð®ð¿ððð®ðºð²
              Compress, decompress or benchmark using dictionary dÌ²iÌ²cÌ²tÌ²iÌ²oÌ²âÌ²
              nÌ²aÌ²rÌ²yÌ²NÌ²aÌ²mÌ²eÌ². Compression and decompression must use the  same
              dictionary  to be compatible. Using a different dictionary
              during decompression will either abort due  to  decompresâ
              sion error, or generate a checksum error.

       -ð³ --[ð»ð¼-]ð³ð¼ð¿ð°ð²
              This option has several effects:

              If  the  target  file already exists, overwrite it without
              prompting.

              When used with --ð±ð²ð°ð¼ðºð½ð¿ð²ðð and ð¹ðð° cannot  recognize  the
              type  of  the  source  file, copy the source file as is to
              standard output. This allows ð¹ðð°ð°ð®ð  --ð³ð¼ð¿ð°ð²  to  be  used
              like  ð°ð®ð (ð­) for files that have not been compressed with
              ð¹ðð°.

       -ð° --ððð±ð¼ðð --ðð¼-ððð±ð¼ðð
              Force write to standard output, even if it is the console.

       -ðº --ðºðð¹ðð¶ð½ð¹ð²
              Multiple  input  files.  Compressed  file  names  will  be
              appended  a  .ð¹ðð° suffix. This mode also reduces notificaâ
              tion level. ð¹ðð° -ðº has a behavior equivalent  to  ð´ðð¶ð½  -ð¸
              (it preserves source files by default).

       -ð¿     operate recursively on directories. This mode also sets -ðº
              (multiple input files).

       -ð#    Block size [4-7](default : 7)
              -ðð°= 64KB ; -ðð±= 256KB ; -ðð²= 1MB ; -ðð³= 4MB

       -ðð    Block Dependency  (improves  compression  ratio  on  small
              blocks)

       --ð³ð®ðð[=#]
              switch  to  ultra-fast  compression  levels.  If =# is not
              present, it defaults to  ð­.  The  higher  the  value,  the
              faster the compression speed, at the cost of some compresâ
              sion ratio. This setting overwrites compression  level  if
              one  was set previously. Similarly, if a compression level
              is set after --ð³ð®ðð, it overrides it.

       --[ð»ð¼-]ð³ð¿ð®ðºð²-ð°ð¿ð°
              Select frame checksum (default:enabled)

       --[ð»ð¼-]ð°ð¼ð»ðð²ð»ð-ðð¶ðð²
              Header includes original size (default:not present)
              Note : this option can only be activated when the original
              size  can  be  determined, hence for a file. It wonÂ´t work
              with unknown source size, such as stdin or pipe.

       --[ð»ð¼-]ðð½ð®ð¿ðð²
              Sparse mode support (default:enabled on file, disabled  on
              stdout)

       -ð¹     Use Legacy format (typically for Linux Kernel compression)
              Note : -ð¹ is not compatible with -ðº (--ðºðð¹ðð¶ð½ð¹ð²) nor -ð¿

   ðððµð²ð¿ ð¼ð½ðð¶ð¼ð»ð
       -ð --ðð²ð¿ð¯ð¼ðð²
              Verbose mode

       -ð¾ --ð¾ðð¶ð²ð
              Suppress  warnings and real-time statistics; specify twice
              to suppress errors too

       -ðµ -ð --ðµð²ð¹ð½
              Display help/long help and exit

       -ð --ðð²ð¿ðð¶ð¼ð»
              Display Version number and exit

       -ð¸ --ð¸ð²ð²ð½
              Preserve source files (default behavior)

       --ð¿ðº   Delete source files on successful  compression  or  decomâ
              pression

       --     Treat all subsequent arguments as files

   ðð²ð»ð°ðµðºð®ð¿ð¸ ðºð¼ð±ð²
       -ð¯#    Benchmark file(s), using # compression level

       -ð²#    Benchmark  multiple  compression  levels,  from  b#  to e#
              (included)

       -ð¶#    Minimum evaluation time in seconds [1-9] (default : 3)

ðððð
       Report bugs at: https://github.com/lz4/lz4/issues

ðððððð
       Yann Collet

lz4 1.8.3                       September 2018                          LZ4(1)
