Définir le mot de passe pour l'utilisateur de Postgres Ubuntu
sudo -u postgres psql
ALTER USER <myuser> WITH PASSWORD 'mypassword';
Classy Answer
sudo -u postgres psql
ALTER USER <myuser> WITH PASSWORD 'mypassword';
ALTER USER user_name WITH PASSWORD 'new_password';
ALTER USER user_name WITH PASSWORD 'new_password';
sudo -u postgres psql
\password postgres