title: Searching a file name with just part of file name known
body: <p>I have searched the entire forum but couldn't find what i was looking for.
  I have few file's in a folder i know just a part of the file name. Example <code>stackoverflow_newuser_6.2.txt</code> and <code>stackoverflow_olduser_6.2.txt</code>. I know that file name contains olduser and newuser. </p>
  
  <p>How can i search for file based on substring. </p>