disable NOTICES in psql output

SET client_min_messages TO WARNING;

That could be set only for the session or made persistent with ALTER ROLE or ALTER DATABASE.

Or you could put that in your ".psqlrc".

Probably the most comprehensive explanation is on Peter Eisentrauts blog entry here (Archive)

I would strongly encourage that the original blog be studied and digested but the final recommendation is something like :

PGOPTIONS='--client-min-messages=warning' psql -X -q -a -1 -v ON_ERROR_STOP=1 --pset pager=off -d mydb -f script.sql