Re: Extracting indiviual files or directories from XYZ.tar.xz - Possible?
On 2025-08-09 22:47:30 -0700, Michael Paoli wrote:
> Length of a file can change while tar is backing it up, tar generally
> handles this,
> though it may complain/warn about it.
> And to the compression formats, it's just a stream of data,
> they know nothing about tar. So, the blocks of compressed data may
> have part of one large file, or maybe thousands of files. The compression
> formats generally don't know or care when it comes to tar archive or the like,
> so there's not really much info they could provide to tar about what's within
> ... for the most part all they really know is its data, and perhaps
> also bits like
> how long the block is compressed, and uncompressed, and perhaps some
> hash of that data or the like.
This is why I said that in the hope to offer a better chance of
optimization of compression, it is better to make "tar" do the
compression (either internally or with an external xz). xz offers
a way to choose at what points compressed blocks will be split.
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / Pascaline project (LIP, ENS-Lyon)
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