title: No such file or directory on Mac terminal for python
body: <p><code>hello.py</code> is my first python program. It is saved on my desktop.</p>
  <p>In the terminal I write in front of</p>
  <pre><code>user@AA-MacBook-Air ~ % python3 hello.py
  </code></pre>
  <p>The error is</p>
  <pre class="lang-none prettyprint-override"><code>can't open file 'hello.py': [Errno 2] No such file or directory
  </code></pre>
  <p>Kindly help me understand the problem and solve it.</p>