title: Grepping out a block of text, regex
body: <p>Given a large log file, what is the best way to grep a block of text? </p>
  
  <pre><code>text to be ignored
  more text to be ignored
  ---                                 &lt;---- start capture here
  lots of 
  text with separators like "---"
  ---
  spanning 
  multiple lines
  ---                                 &lt;---- end capture here
  text to be ignored
  more text to be ignored
  </code></pre>
  
  <p>What is known?</p>
  
  <ul>
  <li>Max number of characters in line (55 but may be less)</li>
  <li>Number of lines in a block</li>
  <li>Separator (which may repeat itself)</li>
  </ul>
  
  <p>What regular expression would match this block? Desired output: list of blocks of text.</p>
  
  <p>Please assume Linux command line environment</p>