    Description

    Lzip is a lossless data compressor with a user interface similar to the one
    of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov
    chain-Algorithm' (LZMA) stream format, chosen to maximize safety and
    interoperability. Lzip can compress about as fast as gzip (lzip -0) or
    compress most files more than bzip2 (lzip -9). Decompression speed is
    intermediate between gzip and bzip2. Lzip is better than gzip and bzip2 from
    a data recovery perspective. Lzip has been designed, written, and tested
    with great care to replace gzip and bzip2 as the standard general-purpose
    compressed format for unix-like systems.

    For compressing/decompressing large files on multiprocessor machines plzip
    can be much faster than lzip at the cost of a slightly reduced compression
    ratio.

    For creation and manipulation of compressed tar archives tarlz can be more
    efficient than using tar and plzip because tarlz is able to keep the
    alignment between tar members and lzip members.

    The lzip file format is designed for data sharing and long-term archiving,
    taking into account both data integrity and decoder availability:

       * The lzip format provides very safe integrity checking and some data
         recovery means. The program lziprecover can repair bit flip errors
         (one of the most common forms of data corruption) in lzip files, and
         provides data recovery capabilities, including error-checked merging
         of damaged copies of a file.

       * The lzip format is as simple as possible (but not simpler). The lzip
         manual provides the source code of a simple decompressor along with a
         detailed explanation of how it works, so that with the only help of the
         lzip manual it would be possible for a digital archaeologist to extract
         the data from a lzip file long after quantum computers eventually
         render LZMA obsolete.

       * Additionally the lzip reference implementation is copylefted, which
         guarantees that it will remain free forever.

    A nice feature of the lzip format is that a corrupt byte is easier to repair
    the nearer it is from the beginning of the file. Therefore, with the help of
    lziprecover, losing an entire archive just because of a corrupt byte near
    the beginning is a thing of the past.

    Lzip uses the same well-defined exit status values used by bzip2, which
    makes it safer than compressors returning ambiguous warning values (like
    gzip) when it is used as a back end for other programs like tar or zutils.

    Lzip will automatically use for each file the largest dictionary size that
    does not exceed neither the file size nor the limit given. Keep in mind that
    the decompression memory requirement is affected at compression time by the
    choice of dictionary size limit.

    The amount of memory required for compression is about 1 or 2 times the
    dictionary size limit (1 if input file size is less than dictionary size
    limit, else 2) plus 9 times the dictionary size really used. The option '-0'
    is special and only requires about 1.5 MiB at most. The amount of memory
    required for decompression is about 46 kB larger than the dictionary size
    really used.

    When compressing, lzip replaces every file given in the command line
    with a compressed version of itself, with the name "original_name.lz".
    When decompressing, lzip attempts to guess the name for the decompressed
    file from that of the compressed file as follows:

    filename.lz    becomes   filename
    filename.tlz   becomes   filename.tar
    anyothername   becomes   anyothername.out

    (De)compressing a file is much like copying or moving it; therefore lzip
    preserves the access and modification dates, permissions, and, when
    possible, ownership of the file just as 'cp -p' does. (If the user ID or
    the group ID can't be duplicated, the file permission bits S_ISUID and
    S_ISGID are cleared).

    Lzip is able to read from some types of non-regular files if either the
    option '-c' or the option '-o' is specified.

    If no file names are specified, lzip compresses (or decompresses) from
    standard input to standard output. Lzip will refuse to read compressed data
    from a terminal or write compressed data to a terminal, as this would be
    entirely incomprehensible and might leave the terminal in an abnormal state.

    Lzip will correctly decompress a file which is the concatenation of two or
    more compressed files. The result is the concatenation of the corresponding
    decompressed files. Integrity testing of concatenated compressed files is
    also supported.

    Lzip can produce multimember files, and lziprecover can safely recover the
    undamaged members in case of file damage. Lzip can also split the compressed
    output in volumes of a given size, even when reading from standard input.
    This allows the direct creation of multivolume compressed tar archives.

    Lzip is able to compress and decompress streams of unlimited size by
    automatically creating multimember output. The members so created are large,
    about 2 PiB each.

    In spite of its name (Lempel-Ziv-Markov chain-Algorithm), LZMA is not a
    concrete algorithm; it is more like "any algorithm using the LZMA coding
    scheme". For example, the option '-0' of lzip uses the scheme in almost the
    simplest way possible; issuing the longest match it can find, or a literal
    byte if it can't find a match. Inversely, a much more elaborated way of
    finding coding sequences of minimum size than the one currently used by lzip
    could be developed, and the resulting sequence could also be coded using the
    LZMA coding scheme.

    Lzip currently implements two variants of the LZMA algorithm; fast
    (used by option '-0') and normal (used by all other compression levels).

    The high compression of LZMA comes from combining two basic, well-proven
    compression ideas: sliding dictionaries (LZ77/78) and markov models (the
    thing used by every compression algorithm that uses a range encoder or
    similar order-0 entropy coder as its last stage) with segregation of
    contexts according to what the bits are used for.

    The ideas embodied in lzip are due to (at least) the following people:
    Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for the
    definition of Markov chains), G.N.N. Martin (for the definition of range
    encoding), Igor Pavlov (for putting all the above together in LZMA), and
    Julian Seward (for bzip2's CLI).

    LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never have
    been compressed. Decompressed is used to refer to data which have undergone
    the process of decompression.

    Copyright (C) 2008-2021 Antonio Diaz Diaz.

    This file is free documentation: you have unlimited permission to copy,
    distribute, and modify it.

    The file Makefile.in is a data file used by configure to produce the
    Makefile. It has the same copyright owner and permissions that configure
    itself.