title: Find the occurrence of backslash in a string
body: <p>If my string is : <code>aud\ios</code>, how do i check it out for the presence of <code>\</code> in it? </p>
  
  <p>I tried using <code>preg_match('\\' , $string)</code> but it does not work. What's the correct way to achieve this?</p>