title: Why postgresql on mac asks me for password after fresh install?
body: <p>I just installed <code>postgresql</code> on a Macbook with <code>brew install postgresql</code>. Then I try to <code>psql</code>, but it requires password and then show <code>psql: FATAL:  password authentication failed for user "&lt;myname&gt;"</code>.</p>
  
  <p>I have not set up anything, and inputting my mac password does nothing. What should I do now?</p>