title: Replace an asterisk (*) using Perl regular expression
body: <p>I have the following string:</p>
  
  <p><code>$_='364*84252';</code></p>
  
  <p>The question is: how to replace <code>*</code> in the string with something else? I've tried <code>s/\*/$i/</code>, but there is an error:  <code>Quantifier follows nothing in regex</code>. On the other hand <code>s/'*'/$i/</code> doesn't cause any errors, but it also doesn't seem to have any effect at all.</p>