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.

The format is:

hostname:port:database:username:password

Then, set the file's mode to 0600. Otherwise, it will be ignored.

chmod 600 ~/.pgpass

See the Postgresql documentation libpq-pgpass for more details.