How do I set up automatic backups?

Greetings again!

A few days ago, I visited a customer's site to talk about administering
our system, which is developed around a PostGres database.  One of the
topics was how to back up the database.  I described the process of
using PgAdmin to back up and restore a database, and I said a backup
should be done every night.  I was asked how to automate the procedure,
and I couldn't answer.  A database administrator said, "There's got to
be a way.  Otherwise, PostGres wouldn't have survived".  I agree with
him.  The only answers I've found on the Internet involve creating a
password-less account and using that to run pg_dump.  What is the
official best way to automatically back up a PostGres database?

Thank you very much.

RobR