title: How to use GnuPlot to plot a time series chart from a CSV file date and time stored in separate columns?
body: <p>Lets' take this as the data file:</p>
  
  <pre><code>2012-06-01, 01:00, 1
  2012-06-01, 02:00, 2
  2012-06-01, 03:00, 4
  2012-06-01, 04:00, 3
  ...
  2012-06-02, 01:00, 5
  2012-06-02, 02:00, 2
  2012-06-02, 03:00, 1
  2012-06-02, 04:00, 1
  ...
  </code></pre>
  
  <p>I know how to set <code>timefmt</code> and <code>xdata</code> to plot time series when date and time are represented with a single field, but how to plot this with GnuPlot when time and date are stored in separate columns?</p>