xz-utils 4.999.8beta-0ubuntu2 (i386 binary) in ubuntu lucid

 XZ Utils is a set of gzip-style tools for working with files
 compressed with the Lempel-Ziv/Markov-chain compression method.
 It supports two formats: .xz and the older .lzma format. Thus
 it provides two sets of commands: xz, unxz, xzcat, xzgrep, and
 so on; and lzma, unlzma, lzcat, lzgrep, etc.
 .
 Compression is generally good (on par with or better than bzip2),
 decompression fast, and RAM usage high during compression and low
 during decompression.