Bzip2 is a is a freely available, patent free, high-quality data
compressor. It typically compresses files to within 10% to 15% of the best available techniques
(the PPM family of statistical
compressors), whilst being around twice as fast at compression and six times faster at
Why would I want to use it?
Because it compresses well. So it packs more stuff into your overfull
disk drives, distribution CDs, floppy disks, Zip disks, backup tapes, ...
whatever. And/or it reduces your phone bills, customer download times, long
distance network traffic, ... whatever. Pretty obvious really. Who's arguing?
It's not the world's fastest compressor, but it's still fast enough to be
Because it's open-source (BSD-style license), and, as far as I know,
patent-free. (To the best of my knowledge. I can't afford to do a full
patent search, so I can't guarantee this. Caveat emptor). So you can use it
for whatever you like. Naturally, the source code is part of the
Because it supports (limited) recovery from media errors. If you are
trying to restore compressed data from a backup tape or disk, and that data
contains some errors, bzip2 may still be able to decompress those parts of
the file which are undamaged.
Because you already know how to use it. bzip2's command line flags are
similar to those of GNU Gzip, so if you know how to
use gzip, you know how to use bzip2.
Because it's very portable. It should run on any 32 or 64-bit machine
with an ANSI C compiler. The distribution should compile unmodified on Unix
and Win32 systems. Earlier versions have been ported with little
difficulty to a large number of weird and wonderful systems.
Because the documentation tells you how and to what extent I've tested it, and you can decide for yourself whether or not to entrust your data
to it. For 1.0.0, the test volume is about 6 gigabytes in circa 120,000 files.
The code is organised as a library, with a programming
interface. The bzip2 program itself is a client of the library. You can
use the library in your own programs, to directly read and write .bz2 files, or
even just to compress data in memory using the bzip2 algorithms.