Re: How to add a new psql command ?

You can also shell out to a command with \! and send data one way using a
combo of \gset and \setenv, then bundle up the whole "function" as a .sql
file you include when you want it with \i. For example here's a snippet I
use to get the session pid, export it, then fire up another tmux pane
running gdb attached to my session and then continue:

select pg_backend_pid() pid \gset
\setenv PID :'pid'
\! tmux split-window -h
\! tmux send-keys 'gdb /usr/bin/postgres ' $PID 'C-m' 'cont' 'C-m'

This trick is also useful to export snapshot ids to subprocesses that need
read consistent views with each other.

-Michel

On Thu, Feb 7, 2019 at 3:03 AM Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
wrote:

> Hi
>
> čt 7. 2. 2019 v 11:40 odesílatel Quentin Di-Fant <quentin(dot)difant(at)gmail(dot)com>
> napsal:
>
>> Hello,
>>
>> I was wondering : is it possible to add directly a new psql command which
>> can be run anytime in our PostgreSQL interpreter like any other normal psql
>> commands ?
>>
>> I explain myself : in the PostgreSQL interpreter, when the command "\h"
>> or "\help" is written in the shell, we can see all the commands we have at
>> our disposal. We can also of course write our proper functions, in python
>> scripts for example, and run them direclty in one of our databases. But I
>> was wondering if it was possible to add directly a command, like \copy,
>> \select, .... For example, let's say I create a new command called \resume
>> which will call my own-made python script, and I would want this command to
>> be part of the list of commands we see when we type \h.
>>
>> Is it even possible ? And if it's possible, how can I achieve that ?
>>
>> Thanks for your attention and I thank you in advance for all the
>> informations you will possibly give me.
>>
>
> It is not possible. psql is not designed to be enhanced.
>
> you can use psql variables for this purpose partially
>
> postgres=# \set x 'select 1;'
> postgres=# :x
> ┌──────────┐
> │ ?column? │
> ╞══════════╡
> │ 1 │
> └──────────┘
> (1 row)
>
>
>
>
>> Cordially.
>>
>