title: PostgreSQL error: Fatal: role "username" does not exist
body: <p>I'm setting up my PostgreSQL 9.1. I can't do anything with PostgreSQL: can't <code>createdb</code>, can't <code>createuser</code>; all operations return the error message</p>
  
  <pre><code>Fatal: role h9uest does not exist
  </code></pre>
  
  <p><code>h9uest</code> is my account name, and I <code>sudo apt-get install</code> PostgreSQL 9.1 under this account.<br>
  Similar error persists for the <code>root</code> account.</p>