This post is mostly a reminder for me in the future. However, others may find it useful also.

I love Postgres but more often than not I get frustrated and confused trying to get authentication working with a new database. By looking through the Deprec source code, I pulled out these two lines of code and so far they haven’t failed me:

su - postgres -c "createuser -P -D -A -E $DBUSER"
su - postgres -c "createdb -O $DBUSER $DBNAME"

Of course, replace $DBUSER and $DBNAME with your desired username and database name, or define them as shell variables. The $DBUSER creates that user as the owner of the database (so it has permission to read/write etc).