Horton

Re: Variable substitution in psql backtick expansion

Fabien COELHO <coelho@cri.ensmp.fr>

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From: Fabien COELHO <coelho@cri.ensmp.fr>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Daniel Verite <daniel@manitou-mail.org>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Developers <pgsql-hackers@postgresql.org>
Date: 2017-04-02T07:52:25Z
Lists: pgsql-hackers 
> For this case can be nice to have function that returns server version as
> number
>
> some like version_num() .. 10000

Another possible trick to get out of a script which does not support \if,
relying on the fact that the unexpected command is simply ignored:

   -- exit version below 10
   \if false
     \echo 'script requires version 10 or better'
     \q
   \endif

Also possible but less informative on errors:

   \set ON_ERROR_STOP on
   \if false \endif

-- 
Fabien.

Commits

  1. Add psql variables showing server version and psql version.

  2. Reformat psql's --help=variables output.

  3. Remove reinvention of stringify macro.

  4. Allow psql variable substitution to occur in backtick command strings.