On 07/07/2014 02:56 PM, Reindl Harald wrote:
>
>
> Am 07.07.2014 14:53, schrieb Ljubomir Ljubojevic:
>> Also, check needs to be made if xz supports multitrheading like pk7zip
>
> enter "xz --help" would have answered this
>
> --threads=NUM
> use at most NUM threads; the default is 1;
> set to 0 to use the number of processor cores
>
> Usage: xz [OPTION]... [FILE]...
> Compress or decompress FILEs in the .xz format.
>
> -z, --compress force compression
> -d, --decompress, --uncompress
> force decompression
> -t, --test test compressed file integrity
> -l, --list list information about .xz files
> -k, --keep keep (don't delete) input files
> -f, --force force overwrite of output file and (de)compress links
> -c, --stdout, --to-stdout
> write to standard output and don't delete input files
> -0 ... -9 compression preset; default is 6; take compressor *and*
> decompressor memory usage into account before using 7-9!
> -e, --extreme try to improve compression ratio by using more CPU time;
> does not affect decompressor memory requirements
> -T, --threads=NUM use at most NUM threads; the default is 1; set to 0
> to use the number of processor cores
> -q, --quiet suppress warnings; specify twice to suppress errors too
> -v, --verbose be verbose; specify twice for even more verbose
> -h, --help display this short help and exit
> -H, --long-help display the long help (lists also the advanced options)
> -V, --version display the version number and exit
>
Ok, I spent several minutes on this.
xz --long-help and man xz are much more informative.
https://en.wikipedia.org/wiki/Xz:
"Design
xz compresses single files as input, and does not bundle multiple files
into a single archive. It is therefore common to compress a file that is
itself an archive, such as those created by the tar or cpio Unix
programs.[2]"
"xz is a lossless data compression program and file format which
incorporates the LZMA compression algorithm.
xz can be thought of as a stripped down version of the 7-Zip program. xz
has its own file format rather than the .7z format used by 7-Zip (which
lacks support for Unix-like file system metadata[2])."
https://en.wikipedia.org/wiki/7-Zip:
"By default, 7-Zip creates 7z format archives with a .7z file extension.
Each archive can contain multiple directories and files. As a container
format, security or size reduction are achieved using a stacked
combination of filters. These can consist of pre-processors, compression
algorithms, and encryption filters."
So either tar.xz or 7z container, and looks like LZM2 is only option,
with several switches for xz for block reduction.
And, no, --help does not actually help with assessing if xz is viable
replacement for some particular purpose, testing is needed.
P.S. You should REALLY fix your mail client, to sent replies to
centos@xxxxxxxxxx so that conversations is seen by others (it looks like
you reply 99% to the person instead back to the list).
--
Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe
StarOS, Mikrotik and CentOS/RHEL/Linux consultant
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