tar & compression

[Joe Altman]

On Thu, Jan 17, 2013 at 09:29:55PM -0500, Fbsd8 wrote:
> The man page for tar command says there a 4 different compress types
> you can use, xz, bzip, bzip2 and gzip.

xz uses Lempel-Ziv-Markov chain algorithm.
bzip2 uses Burrows-Wheeler transform.
 
> Which one is the fastest and compresses the most?

Sounds like a case of fast or cheap: choose one.

Or is it fast or expensive? Or maybe it's all just bragging.

OTOH, apropos compression may be instructive:

7z (and related)

> I am using -z option for gzip and it sure is slow.
> Hoping one of the other zip options are better.
> What do you guys use?

Used to use bzip2 and tar. Nowadays I just place files on a big disk
that only runs when I backup my bits.

> Another question about tar is can I have tar create a compressed bkup
> of 2 files and a directory tree all in single tar command?

For directories, I've used this:

tar -cf - -C srcdir . | tar xpf - -C destdir

The tar man page has this:

tar -czf file.tar.gz source.c source.h 

Since anything is a file, it seems to me it would work on a directory
with this:

tar -czf file.tar.gz source.c source.h /path/to/directory

I also note that (since you've mentioned mtree) the man page on tar
provides an example on mtree. Could this be applied to your needs?

Best regards,

Joe