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Date: Sat, 2 Jul 2011 08:38:26 +0200
From: Polytropon <freebsd@edvax.de>
To: Manish Jain <invalid.pointer@gmail.com>
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Cc: freebsd-questions@freebsd.org
Subject: Re: What is xz ?
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On Sat, 02 Jul 2011 11:53:17 +0530, Manish Jain wrote:
> 
>    Hi all,
>    I just downloaded FreeBSD-8.2-RELEASE-i386-dvd1.iso.xz and the md5
>    checksum is correct. Can someone please tell me what does that xz at
>    the end stand for ? It looks like it stands for some kind of
>    compression (gzip/bzip2/some new format), but I can't figure out
>    exactly which one.

It's xz compression, archivers/xz from ports, which is
a LZMA compression and decompression tool (next to com-
pression and uncompression, there are tools comparable
to zcat, zgrep, zless and so on).

Some details from the package description:

XZ Utils is free general-purpose data compression software with a
high compression ratio.  XZ Utils is the successor to LZMA Utils.

The core of the XZ Utils compression code is based on the LZMA SDK.
The primary compression algorithm is currently LZMA2, which is used
inside the .xz container format.  With typical files, XZ Utils
creates output 30% smaller than gzip and 15% smaller than bzip2.

The XZ Utils package consists of several components:

* liblzma is a compression library with an API similar to that of zlib.
* xz is a command line tool with syntax similar to that of gzip.
* xzdec is a decompression-only tool smaller than the full-featured xz tool.
* A set of shell scripts (xzgrep, xzdiff, etc.) have been adapted
  from gzip to ease viewing, grepping, and comparing compressed files.
* Emulation of the command line tools of LZMA Utils eases transition
  from LZMA Utils to XZ Utils.

WWW: http://tukaani.org/xz/


-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...