title: Regex to insert newlines into large block of text at specific locations
body: <p>I have a rather large text file that has a bunch of missing newlines, meaning that it's a mess. I need to break it up into appropriate lines.</p>
  
  <p>The text looks something like this now:</p>
  
  <pre><code>12345 This is a chunk 23456 This is another chunk 34567 This is yet another chunk 45678 This is yet more chunk 56789 Yet another piece of text
  </code></pre>
  
  <p>I need a regex that will insert a newline (CR/LF pair) before each group of five digits, resulting in something like this:</p>
  
  <pre><code>12345 This is a chunk 
  23456 This is another chunk 
  34567 This is yet another chunk 
  45678 This is yet more chunk 
  56789 Yet another piece of text
  </code></pre>
  
  <p>It can insert one before the first group of digits or not; that I can deal with.</p>
  
  <p>Any ideas? Thanks.</p>