rzip64 [OPTIONS] <files...>
rzip64 is a file compression program designed for very large files. When processing large chunks of input data it takes advantage of repetitiv appearing byte patterns over long distances.
rzip64 can utilize multiple CPU cores. rzip64 can also be interrupted at any time and be restarted later.
Here is a summary of the options to rzip64.
-0 fastest (worst) compression -6 default compression -9 slowest (best) compression -d decompress -f force overwrite of any existing files -G use slices (stop-and-go mode) -h print this help text -j n use n cores in parallel -k keep existing files -o filename specify the output file name -P show compression progress -S suffix specify compressed suffix (default \&'\&.rz\&') -V show version
Just install rzip64 in your search path.
Compressing a large file takes time an imposes a considerable load on the machine. It is therefore desireable to run compression tasks only at times where no users are working on the machine.
rzip64 can therefore be interrupted at any time by a simple kill command. When rzip64 is restarted later it will continue the compression task until the job is completed. One may even change the number of cores when restarting.
The ideas behind rzip64 were first implemented in 1998 during the work on rsync. That version was too slow to be practical, and was replaced by version 2.1 in 2003.
The stop-and-go option was added in 09/2010 (version 2.2).
Multicore support was added in 12/2010. The version number was advanced to 3.0 since rzip64 with multiple treads requires a considerable amount of memory address space that can typically be provided by 64 bit environments only. It is not a matter of physical RAM modules but of virtual address space. Each cpu core requires about 900 MByte address space.
One can still compile an run rzip64 in 32 bit environments (while using only a small number of cpu cores) but that is no longer recommended.
The file format for rzip64 is fully compatible to rzip 2.1 and 2.2 .
Unlike most Unix compression programs, rzip64 cannot compress or decompress to or from standard input or standard output. That can possibly be changed but appears to make not much sense when -G is in use.
If you wish to report a problem or make a suggestion then please email rzip64-at-GHSi.eu
Source code and binary packages are available here:
Some additional background infos and benchmarking results may be found here.
Different people have put work in the development of rzip64. Our thanks include
rzip64 is released under the GNU General Public License version 3 or later. Please see the file COPYING for license details.