I've been learning about the syntax and usage of tar and came across star.

I've read this paragraph from the star manpage:

Star includes the first free implementation of POSIX.1-2001 extended tar headers. The POSIX.1-2001 extended tar headers define a new standard way for going beyond the limitations of the historic tar format. They allow (among others) to archive all UNIX time stamps in sub-second resolution, files of arbitrary size and filenames without length limitation using UNICODE UTF-8 coding for best exchange compatibility.

and I'm wondering if this still remains true at the present time, or whether tar has caught up in this aspect.

Most of the documentation that I've found is at least a decade old. I've also looked at the tar changelog over the last 10 years and can't find anything that states that it follows the above "extended tar headers".

  • You didn't even include your version of RH/Centos. Apr 22 '14 at 7:04
  • 1
    @Pavel Šimerda: you can assume the latest, but the question is more about tarversion here.
    – Ouki
    Apr 22 '14 at 8:11
  • @Ouki: I would rather not assume in this case. And the versions of packages depend on the version of the distribution. Apr 22 '14 at 10:34
  • 2
    I've removed the rhel/centos tags, since it's not important what OS it is on. I'm asking about the programs tar & star themselves. I'm mainly trying to find out if they are any different, or if that was just the case 10-12 years ago. Apr 22 '14 at 12:03
  • 1
    (on a phone, can't put in a real answer) check the GNU tar info page, there is a section about tar formats... It supports several, and explains the differences.
    – derobert
    Apr 22 '14 at 13:33

By comparing these two pages1,2 I found the following:

  • tar supports the POSIX.1-2001 extended tar headers, you can specify this format using
    the --posix switch or --format=posix

  • tar also supports a diff command using --diff or --compare, similar to star.

  • I couldn't find any significant differences between tar and star...

... So I guess I can lay my mind to rest.

1: http://linux.die.net/man/1/star
2: http://www.gnu.org/software/tar/manual/tar.html

  • Tar does not support -diff at all, gtar implements a very simplified variant of the star -diff feature as gtar does not compare all metadata and does not allow to control what to compare.
    – schily
    Aug 25 '15 at 13:18
  • 1
    Also don't forget that many switches are different, you can't simply replace tar with star and keep the rest of your command line
    – bebbo
    Oct 16 '17 at 16:51
  • 1
    A common mistake from people on Linux is to confuse tar with gtar. While star (when called as tar) is 100% compatible to tar, gtar is incompatible. As a result people on Linux learn gtar and believe they learned tar. I even believe that the incompatibilities between star and gtar did not happen if the gtar people first checked for similar star enhancements before introducing own incompatible variants.
    – schily
    Nov 21 '19 at 13:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.