title: Plot multiple series from the same file
body: <p>I've got a data file that looks something like the following:</p>
  
  <pre><code>2016-08-16 dogs 12
  2016-08-16 cats 9
  2016-08-17 cats 4
  2016-08-17 mice 42
  2016-08-17 dogs 6
  </code></pre>
  
  <p>That is: <code>date series count</code>.</p>
  
  <p>Note that the series are not in a consistent order on each day (and might not appear at all).</p>
  
  <p>Further, my input file doesn't have the dates in order either (though I can fix that with <code>sort</code> if I <em>have</em> to), and some of the dates might be missing (because there are no data points for that day).</p>
  
  <p>I'd like to use <strong>gnuplot</strong> to render this. The X-axis should display the date; the Y-axis should display the count; each series should be its own line, with labels in the legend.</p>
  
  <p>I know how to render each series from a separate file, but the series are not fixed, so I'm looking for something that doesn't require that.</p>
  
  <p>How do I do this?</p>
  
  <p><em>Note: I'm using gnuplot 4.4</em></p>