Re: [Bug-tar] Re: AMTAR brokenness

[Paul Eggert]

Alexandre Duret-Lutz <address@hidden> writes:

> How about this scheme:

In the light of later discussion, how about this scheme instead?

  Use the first of the following commands that works:

    tar --format=ustar
    tar
    pax -x ustar

I wouldn't bother with POSIXLY_CORRECT=1 or "tar -o", as they don't
really help much these days.

> On second though, shouldn't we try to use pax first?  tar is no
> longer a POSIX requirement, right?

The "tar" command has never been a POSIX requirement.  However, "pax"
has never caught on, for various reasons, and it hasn't been
road-tested as much as "tar" has.  It makes sense to use "pax" if
"tar" is not available, but I wouldn't make "pax" my first choice.

> Also do we really need to try `-o'?

I vaguely recall that RMS used to suggest -o in the GNU coding
standards, for compatibility with v7 'tar', but that requirement is no
longer necessary (it's not in the standards now, anyway).

> Besides GNU tar, is there some tar implementation that does not
> default to the ustar format?

Many tar implementations have trouble with path names longer than 99
bytes.  This includes the current GNU tar official latest non-alpha
release (which is buggy in this area).  It would be reasonable to add
an automake option that checks for longer-than-99-byte file names, for
people who are worried about such things.  But I don't think it needs
to be high priority.