title: A Regex that will never be matched by anything
body: <p>What's your thought - what does a Regex look like, that will never be matched by any string, ever!</p>
  <p><strong>Edit</strong>: Why I want this? Well, firstly because I find it interesting to think of such an expression and secondly because I need it for a script.</p>
  <p>In that script I define a dictionary as <code>Dictionary&lt;string, Regex&gt;</code>. This contains, as you see, a string and an expression.</p>
  <p>Based on that dictionary I create methods that all use this dictionary as only reference on how they should do their work, one of them matches the regexes against a parsed logfile.</p>
  <p>If an expression is matched, another <code>Dictionary&lt;string, long&gt;</code> is added a value that is returned by the expression. So, to catch any log-messages that are not matched by an expression in the dictionary I created a new group called &quot;unknown&quot;.</p>
  <p>To this group everything that didn't match anything other is added. But to prevent the &quot;unknown&quot;-expression to mismatch (by accident) a log-message, I had to create an expression that is most certainly never matched, no matter what string I give it.</p>