Re: Link t the souce code

Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com> writes:
> On 21.07.21 19:21, Alvaro Herrera wrote:
>> Oh, so the current `tar x` knows to uncompress the file without any
>> additional options? I've been pointlessly adding 'z', 'j', 'a' for years ...
>> That means we can remove the `gunzip` line and replace it with nothing.

> Unless you want to assume GNU tar, the gunzip is still necessary.

That seems overly conservative. On my Mac, Apple has kindly provided

$ tar --version
bsdtar 3.3.2 - libarchive 3.3.2 zlib/1.2.11 liblzma/5.0.5 bz2lib/1.0.6

and in case the mentioned libraries aren't enough clue, it does indeed
seem to work like GNU tar for this purpose:

$ tar tf postgresql-10.16.tar.bz2 | head -5
postgresql-10.16/
postgresql-10.16/.dir-locals.el
postgresql-10.16/contrib/
postgresql-10.16/contrib/tcn/
postgresql-10.16/contrib/tcn/tcn.control

A nearby FreeBSD box provides similar results. So the proposed
instructions probably work fine on most *BSD machines. I also
looked on Solaris 11, and here's what "man tar" has to say there:

j

c mode only. Compress the resulting archive with bzip2. In extract
or list modes, this option is ignored. The implementation recog-
nizes bzip2 compression type automatically when reading archives.
Upgrade/replace first decompresses and then applies the same mecha-
nism to compress the archive automatically.

I think this is another case of a GNUism that's become close
enough to universal that we don't need to be pedantic about it.

regards, tom lane