From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
cc: Alvaro Herrera <alvherre@alvh.no-ip.org>,
        "Jonathan S. Katz" <jkatz@postgresql.org>,
        "Daniel Westermann (DWE)" <daniel.westermann@dbi-services.com>,
        "pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
Subject: Re: Link t the souce code
In-reply-to: <064d5f63-116d-3291-0d5d-88748464b448@enterprisedb.com>
References: <202107211721.pnmoavcgidqb@alvherre.pgsql>
 <064d5f63-116d-3291-0d5d-88748464b448@enterprisedb.com>
Comments: In-reply-to Peter Eisentraut <peter.eisentraut@enterprisedb.com>
	message dated "Wed, 21 Jul 2021 20:09:00 +0200"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <715018.1626892609.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Wed, 21 Jul 2021 14:36:49 -0400
Message-ID: <715019.1626892609@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/715019.1626892609%40sss.pgh.pa.us>
Precedence: bulk

Peter Eisentraut <peter.eisentraut@enterprisedb.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 yea=
rs ...
>> 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  ext=
ract
           or  list  modes,  this option is ignored. The implementation re=
cog-
           nizes bzip2 compression type automatically when  reading  archi=
ves.
           Upgrade/replace first decompresses and then applies the same me=
cha-
           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