psql exit code

I'm running:

ON_ERROR_STOP="on" PGPASSFILE="/somewhere" psql dbname username -f
script.sql
(or alternatively <script.sql)

echo $?
always returns 0 even when sql is clearly wrong.

If I do:
ON_ERROR_STOP="on" PGPASSFILE="/somewhere" psql dbname username -c
"selectz 1 from pippo;"

echo $?
returns 1

psql (PostgreSQL) 8.3.4

How can I know if something went wrong other than parsing the output?

Thanks

--
Ivan Sergio Borgonovo
http://www.webthatworks.it