title: Character to character regex when character the same
body: <p>I'm trying to capture the text in a large markdown doc from on ## Header to the next for export into separate files. </p>
  
  <pre><code>##(.*?)(?=##)
  </code></pre>
  
  <p>Don't work because the initial ## is the same as the Positive Lookahead ##.</p>
  
  <p>Is there a way to capture everything between each ##? Including the first ## but not the second ##.</p>
  
  <pre><code>Sample Text
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