title: gnuplot to plot histogram with lines
body: <p>I've two column data as:</p>
  
  <pre><code>9   17.52
  11  29.77
  7   62.75
  11  36.15
  7   30.46
  7   52.5
  9   65.26
  9   90.05
  14  101.87
  12  86.88
  15  74.78
  </code></pre>
  
  <p>And want that first column be plotted as histogram according to index of y2, and second column be plotted as line according to index of y1. Anyone has ideas?</p>