| XZ Utils for Debian |
| =================== |
| |
| Contents: |
| 1. Differences from standard XZ Utils |
| 2. History |
| 3. LZMA Utils compatibility |
| 4. Configuration |
| |
| Differences from standard XZ Utils |
| ---------------------------------- |
| |
| * The soname of standard liblzma was bumped to 5.0.0, while Debian |
| liblzma remains at 2.0.0. |
| |
| * Some corners of the liblzma API (like layout of reserved fields) |
| have therefore been maintained at an older version in Debian |
| liblzma. Pre-compiled applications built against liblzma on |
| other distributions are likely not to work on this version of |
| Debian if an additional compatibility library is not installed. |
| |
| See /usr/share/doc/liblzma2/README.Debian for details. |
| |
| History |
| ------- |
| |
| XZ Utils should have been called LZMA Utils 4.42, but it came too late. |
| The old .lzma file format has some problems, worst of which is the lack |
| of magic number, but it gets enough use to still need to be supported. |
| See /usr/share/doc/xz-utils/history.txt.gz for the full story. |
| |
| LZMA Utils compatibility |
| ------------------------ |
| |
| To support old scripts and muscle memory, XZ Utils can emulate the |
| legacy LZMA Utils interface. To use this feature, you can install some |
| subset of the following list of symbolic links to your $PATH. |
| |
| lzma, unlzma, lzcat -> /usr/bin/xz |
| lzgrep, lzegrep, lzfgrep -> /usr/bin/xzgrep |
| lzless -> /usr/bin/xzless |
| lzmore -> /usr/bin/xzmore |
| lzdiff, lzcmp -> /usr/bin/xzdiff |
| |
| To allow administrators to keep the old lzma package, the xz-utils |
| package does not provide those links itself. If you would like XZ Utils |
| to provide these commands by default for all users, install the |
| xz-lzma package. |
| |
| Configuration |
| ------------- |
| |
| The memory usage of xz can vary from a few hundred kilobytes to several |
| gigabytes depending on the compression settings. If you would like xz |
| to automatically scale down its settings while compressing to decrease |
| memory usage, you can declare so by adding an option like the |
| following to your environment (e.g., in ~/.profile): |
| |
| XZ_DEFAULTS=--memlimit-compress=256MiB |
| export XZ_DEFAULTS |
| |
| See the "Memory usage" section of the xz(1) manual page for details. |
| |
| -- Jonathan Nieder <jrnieder@gmail.com> Mon, 25 Oct 2010 12:29:25 -0500 |