NAME

       lz4, unlz4, lz4cat - Compress or decompress .lz4 files

SYNOPSIS

       lz4 [OPTIONS] [-|INPUT-FILE] <OUTPUT-FILE>

       unlz4 is equivalent to lz4 -d
       lz4cat is equivalent to lz4 -dc

       When  writing  scripts  that  need to decompress files, it is recommended to always use the name lz4 with
       appropriate arguments (lz4 -d or lz4 -dc) instead of the names unlz4 and lz4cat.

DESCRIPTION

       lz4 is an extremely fast lossless compression algorithm, based on byte-aligned LZ77 family of compression
       scheme.  lz4 offers compression 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.  lz4 supports a command line syntax similar to  gzip(1).   The  native  file
       format is the .lz4 format.

   Concatenation of .lz4 files
       It  is possible to concatenate .lz4 files as is.  lz4 will decompress such files as if they were a single
       .lz4 file. For example:
         lz4 file1  > foo.lz4
         lz4 file2 >> foo.lz4
        then
         lz4cat foo.lz4
        is equivalent to :
         cat file1 file2

OPTIONS

   Short commands concatenation
       In some cases, some options can be expressed using short command -x or long command --long-word .   Short
       commands can be concatenated together. For example, -d -c is equivalent to -dc .  Long commands cannot be
       concatenated.  They must be clearly separated by a space.

   Multiple commands
       When  multiple  contradictory  commands  are  issued  on a same command line, only the latest one will be
       applied.

   Operation mode
       -z, --compress
              Compress.  This is the default operation mode when no operation mode  option  is  specified  ,  no
              other  operation mode is implied from the command name (for example, unlz4 implies --decompress ),
              nor from the input file name (for example, a file extension .lz4 implies --decompress by default).
              -z can also be used to force compression of an already compressed .lz4 file.

       -d, --decompress, --uncompress
              Decompress.  --decompress is also the default operation  when  the  input  filename  has  an  .lz4
              extensionq

       -t, --test
              Test  the  integrity  of compressed .lz4 files.  The decompressed data is discarded.  No files are
              created nor removed.

   Operation modifiers
       -1
               fast compression (default)

       -9
               high compression

       -f, --[no-]force
               This option has several effects:

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

              •  When used with --decompress and lz4 cannot recognize the type of  the  source  file,  copy  the
                 source  file  as  is to standard output.  This allows lz4cat --force to be used like cat(1) for
                 files that have not been compressed with lz4.

       -c, --stdout, --to-stdout
               force write to standard output, even if it is the console

       -m, --multiple
               Multiple file names.
               By default, the second filename is used as the output filename for the compressed file.
               With -m , you can specify any number  of  input  filenames.  Each  of  them  will  be  compressed
              independently, and the resulting name of the compressed file will be filename.lz4

       -B#
               block size [4-7](default : 7)
               B4= 64KB ; B5= 256KB ; B6= 1MB ; B7= 4MB

       -BD
               block dependency (improve compression ratio)

       --[no-]frame-crc
               select frame checksum (default:enabled)

       --[no-]content-size
               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 won't work with unknown source size, such as stdin or pipe.

       --[no-]sparse
               sparse mode support (default:enabled on file, disabled on stdout)

       -l
               use Legacy format (useful for Linux Kernel compression)

   Other options
       -v, --verbose
               verbose mode

       -q, --quiet
               suppress warnings; specify twice to suppress errors too

       -h/-H
               display help/long help and exit

       -V, --version
               display Version number and exit

       -k, --keep
               Don't delete source file.   This  is  default  behavior  anyway,  so  this  option  is  just  for
              compatibility with gzip/xz.

       -b
               benchmark file(s)

       -i#
               iteration loops [1-9](default : 3), benchmark mode only

BUGS

       Report bugs at: https://github.com/Cyan4973/lz4

AUTHOR

       Yann Collet

lz4                                                2015-03-21                                             lz4(1)