LUNZIP(1) User Commands LUNZIP(1)

NAME

lunzip - decompressor for the lzip format

SYNOPSIS

lunzip [options] [files]

DESCRIPTION

Lunzip is a decompressor for the lzip format written in C. Its small
size makes it well suited for embedded devices or software installers
that need to decompress files but don't need compression
capabilities.

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.

Lunzip provides a 'low memory' mode able to decompress any file using
as little memory as 50 kB, irrespective of the dictionary size used
to compress the file. To activate it, specify the size of the output
buffer with the option --buffer-size and lunzip will use the
decompressed file as dictionary for distances beyond the buffer size.
Of course, the larger the difference between the buffer size and the
dictionary size, the more accesses to disc are needed and the slower
the decompression is. This 'low memory' mode only works when
decompressing to a regular file and is intended for systems without
enough memory (RAM + swap) to keep the whole dictionary at once.

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

-c, --stdout
write to standard output, keep input files

-d, --decompress
decompress (this is the default)

-f, --force
overwrite existing output files

-k, --keep
keep (don't delete) input files

-l, --list
print (un)compressed file sizes

-o, --output=<file>
write to <file>, keep input files

-q, --quiet
suppress all messages

-t, --test
test compressed file integrity

-u, --buffer-size=<bytes>
set output buffer size in bytes

-v, --verbose
be verbose (a 2nd -v gives more)

--loose-trailing
allow trailing data seeming corrupt header

If no file names are given, or if a file is '-', lunzip 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... Buffer sizes 12 to 29 are
interpreted as powers of two, meaning 2^12 to 2^29 bytes.

To extract all the files from archive 'foo.tar.lz', use the commands
'tar -xf foo.tar.lz' or 'lunzip -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 lunzip to panic.

The ideas embodied in lunzip are due to (at least) the following
people: Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrei
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).

REPORTING BUGS

Report bugs to lzip-bug@nongnu.org
Lunzip home page: http://www.nongnu.org/lzip/lunzip.html

COPYRIGHT

Copyright (C) 2025 Antonio Diaz Diaz. License GPLv2+: GNU GPL
version 2 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

lunzip 1.15 January 2025 LUNZIP(1)