vorakl

This is an interesting one. What was the version of tar? Was it gnu tar? I wonder, how did you create that archive?

I'm asking this because I was trying to reproduce the same situation and everything seems to be working fine:

  $ tar -C /tmp/root3 -cvf test.tar .
  ./
  ./.config/
  ./.config/test
  ./.local/
  ./var/
  ./var/db/
  ./var/db/xbps/

or even like this

  $ tar -cvf test2.tar root3/
  root3/
  root3/.config/
  root3/.config/test
  root3/.local/
  root3/var/
  root3/var/db/
  root3/var/db/xbps/

No special options were needed. But, if I do it this way, then, there are definitely missing all dot directories:

  $ tar -cvf test2.tar root3/*
  root3/usr/
  root3/usr/bin/
  root3/usr/bin/xbps-uunshare

But this problem is not a tar's problem. That's only because "*" mask doesn't match dot files:

  $ echo root3/*
  root3/usr root3/var

For that purpose, you need to clearly add a dot:

  $ echo root3/.*
  root3/.config root3/.local

Thus, the solution might be

  $ tar -cvf test2.tar root3/.* root3/*
  root3/.config/
  root3/.config/test
  root3/.local/
  root3/usr/
  root3/usr/bin/

But, I'd rather stick to "-C dir/" option instead of relying on "*" mask in this case.

I don't recall ever seeing this approach with sudo. Is it really becoming popular? It used to be just bash, e.g. `curl ... | bash`. But now there is nothing stopping you from putting sudo in that bash script and expecting with a high probability that NOPASSWD: is also there ;)

I asked about options for GNU tar because there is a bit of strange behavior.

To add absolute paths to an archive, there is "-P" option, and man says it works only for creating archives: "Don't strip leading slashes from filenames when creating archives".

To extract absolute paths from the archive, you need to add the "-C /" option, and although the tool says "tar: Strip leading `/' from member names", it will still extract it in the right place because the paths become relative and -C puts them in the root.

However, if you add "-P" during the extraction (which is not mentioned in man), the "strip leading slashes" information disappears.

So if this message bothers someone, "tar -C / -xPf file.tar" will cleanly extract absolute paths from the archive ;)

--no-overwrite-dir (Preserve metadata of existing directories)

This is a really good point! It solves the main problem. I'll add it to the article.

Although that's what, unfortunately, is set by default (at least in GNU tar):

--overwrite-dir (Overwrite metadata of existing directories when extracting (default).)

How do you create a tar archive that "contains absolute paths"?

Yes, but someone has to do the dirty work ;)

This is a good and safe practice. And I think most people do it this way after cleaning up the mess of a badly built tarball at least once :)

Certainly true. I just referred to this definition

"2.4 Other Language-Related Specifications

POSIX.1-2017 is currently specified in terms of the shell command language and ISO C. Bindings to other programming languages are being developed."

I've added a few words and links to other "utilities".

Interesting! I just wonder... How would you do a conditional branching in sed?