title: Postgresql password cannot login
body: <p>I typed the following instruction to set up the postgresql password.</p>
  <pre><code>sudo su - postgres
  psql -U postgres
  alter user postgres with encrypted password 'my_pass';
  \q
  sudo su - postgres
  </code></pre>
  <p>But I met the error.</p>
  <blockquote>
  <p>[sudo] password for postgres:my_pass</p>
  <p>Sorry, try again.</p>
  </blockquote>
  <p>Which thing did I miss?</p>
  <p>I actually set the password.</p>
  <p>Thanks.</p>