How to mimic sqlplus variable behaviour in PostgreSQL

Here is how you can mimic the usage of variables at the prompt using psql and PostgreSQL like you would with oracle and sqlplus/sqlc:

\connect mydb
\prompt 'Enter value for querid: ' v_quid
\echo You entered: :v_quid
SELECT query_sql_text FROM query_store.query_texts_view WHERE query_text_id = :'v_quid';

Run it:

sql -h pgserver1.oric.no -U dbadmin -d postgres -f find_rest_of_statement.sql

Enter value for querid: -7644745457188850826
You entered: -7644745457188850826
                                                    query_sql_text                                                    
----------------------------------------------------------------------------------------------------------------------
      THE QUERY TEXT WILL SHOW UP HERE :-)