title: Match exactly one of each from set of characters
body: <p>I am trying to match a specific set of characters but 1 and only 1 of each.</p>
  
  <p>For example if the set is <code>[abcd]</code>, I want to match string containing these exact characters in any order.</p>
  
  <pre><code>abcd  - true
  bcad  - true
  abc   - false (need all characters)
  abbd  - false
  abcdd - false
  </code></pre>
  
  <p>From what I understand so far there is no easy way to achieve this with RegEx but no answer was conclusive enough.</p>