lz4/programs/README.md

Command Line Interface for LZ4 library

Command Line Interface (CLI) can be created using the make command without any additional parameters. There are also multiple targets that create different variations of CLI:

• lz4 : default CLI, with a command line syntax close to gzip
• lz4c : Same as lz4 with additional support legacy lz4 commands (incompatible with gzip)
• lz4c32 : Same as lz4c, but forced to compile in 32-bits mode

Aggregation of parameters

CLI supports aggregation of parameters i.e. -b1, -e18, and -i1 can be joined into -b1e18i1.

Benchmark in Command Line Interface

CLI includes in-memory compression benchmark module for lz4. The benchmark is conducted using a given filename. The file is read into memory. It makes benchmark more precise as it eliminates I/O overhead.

The benchmark measures ratio, compressed size, compression and decompression speed. One can select compression levels starting from -b and ending with -e. The -i parameter selects a number of iterations used for each of tested levels.

Usage of Command Line Interface

The full list of commands can be obtained with -h or -H parameter:

Usage :
      lz4 [arg] [input] [output]

input   : a filename
          with no FILE, or when FILE is - or stdin, read standard input
Arguments :
 -1     : Fast compression (default)
 -9     : High compression
 -d     : decompression (default for .lz4 extension)
 -z     : force compression
 -f     : overwrite output without prompting
 -h/-H  : display help/long help and exit

Advanced arguments :
 -V     : display Version number and exit
 -v     : verbose mode
 -q     : suppress warnings; specify twice to suppress errors too
 -c     : force write to standard output, even if it is the console
 -t     : test compressed file integrity
 -m     : multiple input files (implies automatic output filenames)
 -l     : compress using Legacy format (Linux kernel compression)
 -B#    : Block size [4-7](default : 7)
 -BD    : Block dependency (improve compression ratio)
--no-frame-crc : disable stream checksum (default:enabled)
--content-size : compressed frame includes original size (default:not present)
--[no-]sparse  : sparse mode (default:enabled on file, disabled on stdout)
Benchmark arguments :
Benchmark arguments :
 -b#    : benchmark file(s), using # compression level (default : 1)
 -e#    : test all compression levels from -bX to # (default: 1)
 -i#    : iteration loops [1-9](default : 3), benchmark mode only

License

All files in this directory are licensed under GPL-v2. See COPYING for details. The text of the license is also included at the top of each source file.