How to pass in password to pg_dump?

Question

I'm trying to create a cronjob to back up my database every night before something catastrophic happens. It looks like this command should meet my needs:

0 3 * * * pg_dump dbname | gzip > ~/backup/db/$(date +%Y-%m-%d).psql.gz

Except after running that, it expects me to type in a password. I can't do that if I run it from cron. How can I pass one in automatically?

Answer 1

Create a .pgpass file in the home directory of the account that pg_dump will run as: see http://www.postgresql.org/docs/8.4/static/libpq-pgpass.html for details of the format (including the last para where it explains it will be ignored if you don't set the mode to 0600).

Answer 2

You should also consider using pg_dump -Fc instead of that gzip pipe sillyness.