title: Perl: Modify variable passed as param to subroutine
body: <p>I need to modify a variable inside a routine, so it keeps the changes after leaving the routine. Here's an example:</p>
  <pre><code>$text = &quot;hello&quot;;
  &amp;convert_to_uppercase($text);
  print $text;
  </code></pre>
  <p>I want to see &quot;HELLO&quot; on the screen, not &quot;hello&quot;.</p>
  <p>The routine would be:</p>
  <pre><code>sub convert_to_uppercase($text){
    &lt;something like $text = uc($text);&gt;
  }
  </code></pre>
  <p>I know how to do it in PHP, but it seems that the parameters are not changed the same way. And, I've been searching everywhere and I couldn't find a concrete answer.</p>