psql in bash scrpts, is possible ?

Hello everyone,

I'm building a small newspaper informations aggregator around postgresql
8.3 and Ubuntu 9.10.
Starting from a previous experience on Oracle DB, I've built and tested
a bunch of functions, triggers, SQL scripts etc... that work flawlessly
(almost !) when I submit them by hand in psql; now I want to pack
everything in a nice shell script, with proper error control, automated
file shuffling,  predefined queries in text files and so on, but I
cannot convince psql that the SQL commands (select, insert or copy...)
it has to handle come from a file.
I can submit  ("\i filename" or "psql --file filename") files that
contains commands, eg starting with "\" but psql does not understand the
same sintax if tne file contains a simple "SELECT * FROM tablex".

Am I uber-newbie or is this a known limitation of psql ? And, in this
case, there is something to overcome this limit and afford my non-techie
user to launch a simple command to print her data or to bulk update tables ?

P.S. Initially I discarded the use of procedural languages (C or ...)
for a quick and simpler solution !

Thanks in advance

Fabio, from North Italy