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3 Invoking lzip
The format for running lzip is:
lzip [options] [files]
Lzip supports the following options:
- ‘-h’
- ‘--help’
Print an informative help message describing the options and exit.
- ‘-V’
- ‘--version’
Print the version number of lzip on the standard output and exit.
- ‘-b bytes’
- ‘--member-size=bytes’
Set the member size limit to bytes. A small member size may degrade compression ratio, so use it only when needed. Valid values range from 100 kB to 64 PiB. Defaults to 64 PiB.
- ‘-c’
- ‘--stdout’
Compress or decompress to standard output. Needed when reading from a named pipe (fifo) or from a device. Use it to recover as much of the uncompressed data as possible when decompressing a corrupt file.
- ‘-d’
- ‘--decompress’
Decompress.
- ‘-f’
- ‘--force’
Force overwrite of output files.
- ‘-F’
- ‘--recompress’
Force recompression of files whose name already has the ‘.lz’ or ‘.tlz’ suffix.
- ‘-k’
- ‘--keep’
Keep (don’t delete) input files during compression or decompression.
- ‘-m bytes’
- ‘--match-length=bytes’
Set the match length limit in bytes. After a match this long is found, the search is finished. Valid values range from 5 to 273. Larger values usually give better compression ratios but longer compression times.
- ‘-o file’
- ‘--output=file’
When reading from standard input and ‘--stdout’ has not been specified, use ‘file’ as the virtual name of the uncompressed file. This produces a file named ‘file’ when decompressing, a file named ‘file.lz’ when compressing, and several files named ‘file00001.lz’, ‘file00002.lz’, etc, when compressing and splitting the output in volumes.
- ‘-q’
- ‘--quiet’
Quiet operation. Suppress all messages.
- ‘-s bytes’
- ‘--dictionary-size=bytes’
Set the dictionary size limit in bytes. Valid values range from 4 KiB to 512 MiB. Lzip will use the smallest possible dictionary size for each member without exceeding this limit. Note that dictionary sizes are quantized. If the specified size does not match one of the valid sizes, it will be rounded upwards by adding up to (bytes / 16) to it.
For maximum compression you should use a dictionary size limit as large as possible, but keep in mind that the decompression memory requirement is affected at compression time by the choice of dictionary size limit.
- ‘-S bytes’
- ‘--volume-size=bytes’
Split the compressed output into several volume files with names ‘original_name00001.lz’, ‘original_name00002.lz’, etc, and set the volume size limit to bytes. Each volume is a complete, maybe multi-member, lzip file. A small volume size may degrade compression ratio, so use it only when needed. Valid values range from 100 kB to 4 EiB.
- ‘-t’
- ‘--test’
Check integrity of the specified file(s), but don’t decompress them. This really performs a trial decompression and throws away the result. Use it together with ‘-v’ to see information about the file.
- ‘-v’
- ‘--verbose’
Verbose mode.
When compressing, show the compression ratio for each file processed. A second ‘-v’ shows the progress of compression.
When decompressing or testing, further -v’s (up to 4) increase the verbosity level, showing status, compression ratio, dictionary size, trailer contents (CRC, data size, member size), and up to 6 bytes of trailing garbage (if any).- ‘-0 .. -9’
Set the compression parameters (dictionary size and match length limit) as shown in the table below. Note that ‘-9’ can be much slower than ‘-0’. These options have no effect when decompressing.
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 ‘--match-length’ and ‘--dictionary-size’ options directly to achieve optimal performance. For example, ‘-9m64’ usually compresses executables more (and faster) than ‘-9’.
Level Dictionary size Match length limit -0 64 KiB 16 bytes -1 1 MiB 5 bytes -2 1.5 MiB 6 bytes -3 2 MiB 8 bytes -4 3 MiB 12 bytes -5 4 MiB 20 bytes -6 8 MiB 36 bytes -7 16 MiB 68 bytes -8 24 MiB 132 bytes -9 32 MiB 273 bytes - ‘--fast’
- ‘--best’
Aliases for GNU gzip compatibility.
Numbers given as arguments to options may be followed by a multiplier and an optional ‘B’ for "byte".
Table of SI and binary prefixes (unit multipliers):
| Prefix | Value | | | Prefix | Value |
| k | kilobyte (10^3 = 1000) | | | Ki | kibibyte (2^10 = 1024) |
| M | megabyte (10^6) | | | Mi | mebibyte (2^20) |
| G | gigabyte (10^9) | | | Gi | gibibyte (2^30) |
| T | terabyte (10^12) | | | Ti | tebibyte (2^40) |
| P | petabyte (10^15) | | | Pi | pebibyte (2^50) |
| E | exabyte (10^18) | | | Ei | exbibyte (2^60) |
| Z | zettabyte (10^21) | | | Zi | zebibyte (2^70) |
| Y | yottabyte (10^24) | | | Yi | yobibyte (2^80) |
Exit status: 0 for a normal exit, 1 for environmental problems (file not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or invalid input file, 3 for an internal consistency error (eg, bug) which caused lzip to panic.
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