title: What is a broken label?
body: <p>Further to my question <a href="https://stackoverflow.com/questions/57208876/add-prefix-to-filenames-using-batch-files?noredirect=1#comment100928231_57208876">here</a>, I need to ask why is it bad (as in results and practice) to have <code>::</code> comment instead of <code>REM</code> within code blocks:</p>
  
  <pre><code>for %%a in (*.pdf) do (
  :: This bad, but why?
  )
  </code></pre>
  
  <p>Can someone explain this to me? And thereby restore my faith in batch files!</p>