title: Batch add string before filename
body: <p>I'm working on a Windows batch file and I need to change name of files in current direcotry.</p>
  
  <p>I have these files:</p>
  
  <pre><code>file1.txt
  file2.txt
  file3.txt
  </code></pre>
  
  <p>and I need to add string "REG~" before each filename like this</p>
  
  <pre><code>REG~file1.txt
  REG~file2.txt
  REG~file3.txt
  </code></pre>
  
  <p>Thank you.</p>