archive files

[David Christensen <dpchrist@holgerdanske.com>]

On 5/4/23 23:46, Jeremy Ardley wrote:
> On 5/5/23 14:21, David Christensen wrote:
> > If the file is a some kind of archive (e.g. tar(1)), both the data
> > and metadata are inside the tarball and the full-circle results
> > should be identical.
> Not quite. The file times are usually changed in the un-tar
> operation. You can usually expect to only have a valid m-time.
>
> In addition, extended attributes such as ACL are not preserved
> without some effort.
>
> There is a further problem in that the owner and group values may be 
> different between systems
>
> The situation is much worse with NTFS on windows where there are 
> alternative data streams and up to 16 timestamps per file per
> datastream.


Thank you for the clarification.


Fortunately, I use the same (user) UID's/GID's on all of my (Unix) 
systems, I have not needed ACL's, and simple use of tar(1) has preserved 
the metadata that I do care about (UID, GID, mode bits, mtime, and 
filename).


How does cpio(1) compare?


How about dump(8) and restore(8)?


AIUI dd(1) produces identical backup/ restore results.  Do you know
otherwise?


David