title: How to verify if variable contains valid filename in Windows Batch
body: <p>I'm asking user to provide filename in Windows Batch, by using this command:</p>
  
  <pre><code>set /p my_filename=Enter filename for this project
  </code></pre>
  
  <p>How can I verify that <code>%my_filename%</code> contains valid Windows filename (not path) and re ask user if it does not?</p>
  
  <p><strong>EDIT</strong>
  The file in question does not yet exists when running the script (it will be created by script)</p>