title: Indian pincode validation regex - Only six digits, shouldn't start with `0`
body: <p>I have tried <a href="https://stackoverflow.com/questions/14132404/regex-accept-numeric-only-first-character-cant-be-0">Regex accept numeric only. First character can&#39;t be 0</a> and <a href="https://stackoverflow.com/questions/7036324/what-is-the-regex-for-any-positive-integer-excluding-0">What is the regex for &quot;Any positive integer, excluding 0&quot;</a> however that didn't work as per my requirements.</p>
  
  <p>I want exact 6 digit numeric number but shouldn't start with <code>0</code></p>
  
  <p>I've tried </p>
  
  <pre><code>^[1-9][0-9]{6}*$
  ^([^0][0-9]){6}$
  ...
  </code></pre>
  
  <p>Need fine tuning.</p>