title: find file starting with a certain string
body: <p>I wonder how to check If a file exist or not : </p>
  
  <p>For Example I have many files : </p>
  
  <pre><code>Boba.txt
  James.txt
  Jamy.txt
  Boby.txt 
  </code></pre>
  
  <p>How can I check if the file starting with Bob exists ?</p>