Re: [PATCH] Stop ALTER SYSTEM from making bad assumptions

Re: Tomas Vondra 2019-08-03 <20190803124111.2aaddumd7url5wmq@development>
> If we really want to give external tools a sensible (and optional) API
> to access the file, a simple command-line tool seems much better. Say we
> have something like
> 
>   pg_config_file -f PATH --set KEY VALUE
>   pg_config_file -f PATH --get KEY

Fwiw, Debian has pg_conftool (based on the perl lib around
PgCommon.pm):

NAME
       pg_conftool - read and edit PostgreSQL cluster configuration files

SYNOPSIS
       pg_conftool [options] [version cluster] [configfile] command

DESCRIPTION
       pg_conftool allows to show and set parameters in PostgreSQL configuration files.

       If version cluster is omitted, it defaults to the default cluster (see user_clusters(5) and postgresqlrc(5)). If
configfileis
 
       omitted, it defaults to postgresql.conf. configfile can also be a path, in which case version cluster is
ignored.

OPTIONS
       -b, --boolean
           Format boolean value as on or off (not for "show all").

       -s, --short
           Show only the value (instead of key = value pair).

       -v, --verbose
           Verbose output.

       --help
           Print help.

COMMANDS
       show parameter|all
           Show a parameter, or all present in this config file.

       set parameter value
           Set or update a parameter.

       remove parameter
           Remove (comment out) a parameter from a config file.

       edit
           Open the config file in an editor.  Unless $EDITOR is set, vi is used.

SEE ALSO
       user_clusters(5), postgresqlrc(5)

AUTHOR
       Christoph Berg <myon@debian.org>

Debian                                                        2019-07-15
PG_CONFTOOL(1)