psql as postgres user code example

Example 1: create db user postgres

sudo -u postgres psql
postgres=# create database mydb;
postgres=# create user myuser with encrypted password 'mypass';
postgres=# grant all privileges on database mydb to myuser;

Example 2: create postgres user

CREATE DATABASE yourdbname;
CREATE USER youruser WITH ENCRYPTED PASSWORD 'yourpass';
GRANT ALL PRIVILEGES ON DATABASE yourdbname TO youruser;