title: Shell: simple way to get all lines before first blank line
body: <p>What's the best shell command to output the lines of a file until you encounter the first blank line? For example:</p>
  
  <pre><code>output these
  lines
  
  but do not output anything after the above blank line
  (or the blank line itself)
  </code></pre>
  
  <p>awk? something else?</p>