title: Why do people write #!/usr/bin/env python on the first line of a Python script?
body: <p>I see these at the top of Python files:</p>
  <pre class="lang-py prettyprint-override"><code>#!/usr/bin/env python
  </code></pre>
  <pre class="lang-py prettyprint-override"><code>#!/usr/bin/env python3
  </code></pre>
  <p>It seems to me like the files run the same without that line.</p>