plzip1

Usage

Overview

Plzip is a massively parallel (multi-threaded) implementation of lzip. Plzip uses the compression library lzlib.

Lzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Lzip uses a simplified form of LZMA (Lempel-Ziv-Markov chain-Algorithm) designed to achieve complete interoperability between implementations. The maximum dictionary size is 512 MiB so that any lzip file can be decompressed on 32-bit machines. Lzip provides accurate and robust 3-factor integrity checking. 'lzip -0' compresses about as fast as gzip, while 'lzip -9' compresses most files more than bzip2. Decompression speed is intermediate between gzip and bzip2. Lzip provides better data recovery capabilities than gzip and bzip2. Lzip has been designed, written, and tested with great care to replace gzip and bzip2 as general-purpose compressed format for Unix-like systems.

Plzip can compress/decompress large files on multiprocessor machines much faster than lzip, at the cost of a slightly reduced compression ratio (0.4 to 2 percent larger compressed files). Note that the number of usable threads is limited by file size; on files larger than a few GB plzip can use hundreds of processors, but on files smaller than 1 MiB plzip is no faster than lzip (not even at compression level -0). The number of threads defaults to the number of processors.

Options

-h, --help

display this help and exit

-V, --version

output version information and exit

-a, --trailing-error

exit with error status if trailing data

-B, --data-size=<bytes>

set size of input data blocks [2x8=16 MiB]

-c, --stdout

write to standard output, keep input files

-d, --decompress

decompress, test compressed file integrity

-f, --force

overwrite existing output files

-F, --recompress

force re-compression of compressed files

-k, --keep

keep (don't delete) input files

-l, --list

print (un)compressed file sizes

-m, --match-length=<bytes>

set match length limit in bytes [36]

-n, --threads=<n>

set number of (de)compression threads [2]

-o, --output=<file>

write to <file>, keep input files

-q, --quiet

suppress all messages

-s, --dictionary-size=<bytes>

set dictionary size limit in bytes [8 MiB]

-t, --test

test compressed file integrity

-v, --verbose

be verbose (a 2nd -v gives more)

-0 .. -9

set compression level [default 6]

--fast

alias for -0

--best

alias for -9

--loose-trailing

allow trailing data seeming corrupt header

--in-slots=<n>

number of 1 MiB input packets buffered [4]

--out-slots=<n>

number of 1 MiB output packets buffered [64]

--check-lib

compare version of lzlib.h with liblz.{a,so}

If no file names are given, or if a file is '-', plzip compresses or decompresses from standard input to standard output. Numbers may be followed by a multiplier: k = kB = 10^3 = 1000, Ki = KiB = 2^10 = 1024, M = 10^6, Mi = 2^20, G = 10^9, Gi = 2^30, etc... Dictionary sizes 12 to 29 are interpreted as powers of two, meaning 2^12 to 2^29 bytes.

The bidimensional parameter space of LZMA can't be mapped to a linear scale optimal for all files. If your files are large, very repetitive, etc, you may need to use the options --dictionary-size and --match-length directly to achieve optimal performance.

To extract all the files from archive 'foo.tar.lz', use the commands 'tar -xf foo.tar.lz' or 'plzip -cd foo.tar.lz | tar -xf -'.

Exit status: 0 for a normal exit, 1 for environmental problems (file not found, invalid command-line options, I/O errors, etc), 2 to indicate a corrupt or invalid input file, 3 for an internal consistency error (e.g., bug) which caused plzip to panic.