Lzip
Lzip is a lossless data compressor based on the LZMA algorithm, with very safe integrity checking and a user interface similar to the one of gzip or bzip2. Lzip decompresses almost as quickly as gzip and compresses better than bzip2, which makes it well suited for software distribution and data archiving.
| Tags | Archiving Compression |
|---|---|
| Licenses | GPLv3 |
| Operating Systems | OS Independent |
| Implementation | C++ |
Recent releases
- 25 Jun 2009 14:17
Changes: A bug introduced in version 1.6 that prevented lzip from decompressing some rare files has been fixed. The integrity checking code catches it, so there is no risk of data loss.
- 23 Jun 2009 08:41
Changes: Decompression time has been reduced by 17%. Decompression support for the "Sync Flush marker" from lzlib has been added. Man pages for lzdiff, lzgrep, and lziprecover have been added to the distribution. Memory use has been reduced to 9x if the input file is smaller than dictionary size limit. Flush calls have been added to decompressor to allow partial recovery of the uncompressed data when decompressing a corrupt file. The dependence of "--test" on the existence of "/dev/null" has been removed. Some "bashisms" have been removed from lzdiff and lzgrep.
- 16 Jun 2009 18:54
Changes: A build problem with the Sun C++ compiler has been fixed.
- 04 Jun 2009 10:53
Changes: Decompression support for the "Sync Flush marker" from lzlib has been added. Some "bashisms" have been removed from lzdiff and lzgrep. The dictionary size for options "-1" to "-4" has been changed.
- 22 May 2009 18:30
Changes: Decompression time has been reduced by 17%. Support for the .tbz extension has been added to lzdiff and lzgrep. Man pages for lzdiff, lzgrep, and lziprecover have been added to the distribution. Maximum memory use has been reduced to 9 times the input file size if the input file is smaller than the dictionary size limit.
- All comments
Recent commentsRe: Other LZMA tools
I think you are right that the standalone 'lzma' program (replacing the older lzmash) has a very basic data format. But still, it works, and is the more established tool. I would be happy for lzip to replace it if lzip is better, but to do that it should include support for decompressing legacy .lzma files.
(I note that the gzip format has provision for alternative compression methods but nobody ever seems to use it.)
> As for lrzip, it is actually
> an extension of rzip---and the two are
> more of a proof-of-concept than a
> realworld-workable format.
The file format may be basic but the tool is very good. It usually compresses better than plain LZMA (the algorithm, used in both lzma-utils and lzip) and faster too. LZMA is better for all-purpose use but for batch compression tasks where you don't mind relatively high memory usage, lrzip can give a big improvement. For some Subversion dump files I back up overnight it gave a fourfold increase in compression for about the same speed.
Re: Other LZMA tools
As I gather, lzma-utils-produced files lack magic identification bytes and a checksum, and if you believe forum archives, lzma-utils did not manage to come up with a suitable new format in more than two years. It is about time lzip came along—7z sounds nice too, but seems to have gotten no ground in the Unix world due to subpar unix integration.
As for lrzip, it is actually an extension of rzip—and the two are more of a proof-of-concept than a realworld-workable format.
Other LZMA tools
An alternative command-line compressor using LZMA is lzmash from lzma-utils. Also interesting is lrzip which adds a preprocessing step before the LZMA compression to give a better speed/tightness tradeoff, at the expense of using more memory.