title: Remove control characters from PHP string
body: <p>How can I remove control characters like STX from a PHP string? I played around with</p>
  
  <pre><code>preg_replace("/[^a-zA-Z0-9 .\-_;!:?äÄöÖüÜß&lt;&gt;='\"]/","",$pString)
  </code></pre>
  
  <p>but found that it removed way to much. Is there a way to remove <em>only</em>
  control chars?</p>