add some parallel compression type

[luvarqpp]

I would like to use more cpu cores than single one.

Add possibility to use pigz, zstd or something similar.

PS: I like that your script is "auditable" in few minutes by simple reading. Consider, if feature like this one, does not make it "too long".

[loomchild]

I wasn't even aware these exist:)

I agree that I'd like to keep it simple. Would you like to propose a PR? If not, I will take a look at it a bit later.

[debuglevel]

That would be great! :-) To set a parallel compression method, additional tools (pigz, pbzip2, pxz) have to be installed and called by the -I pxz argument:

gz: tar -I pigz -cf tarball.tgz files
bz2: tar -I pbzip2 -cf tarball.tbz files
xz: tar -I pxz -cf tarball.txz files

[loomchild]

Thanks for the info!

I can try to integrate those if I find some time, or alternatively feel free to propose a PR.

[loomchild]

Zstd was just added by @ksurl #36. I hope it solves the ticket - if not, please reopen.

[ksurl]

Zstd does support parallel compression with multithreading in the latest version but that version is not available in alpine yet. Pigz would be better if parallel is a must but zstd is pretty fast. Also since tar doesnt support passing flags to the compression program you'd have to use a pipe and change how the script calls it

[luvarqpp]

Also since tar doesnt support passing flags to the compression program you'd have to use a pipe and change how the script calls it

IMHO it is possible to pass parameters. I use this approach:

tar --use-compress-program="pigz --best" -cf filesWithPrefixAsdf.tar.gz Asdf*

Note, that passed program have to support -d parameter (for decompression). If this is not the case (7za binary for example), you can have a look at simple wrapper approach on stack owerflow

[loomchild]

BTW, I have just added an option -x to pass any arguments to Tar (see #28). Perhaps this would be useful in such complex scenarios (unfortunately I can't verify as I am not using parallel compression)