title: plot only specific columns in gnuplot
body: <p>I have a csv file as show below and i want to plot S(on x axis) and B(axis).How do i generate a plot of lines with gnuplot. </p>
  
  <pre><code>    Test_Image,Original_Size
      red-room.png,918394
      Q,S,B,S,C,R
      0,1021763,0.121086,0.00001459,-11.26,-222.18
      1,1061763,0.125086,0.00001459,-11.26,-222.18
      2,1051763,0.121086,0.00001459,-11.26,-222.18
      3,1041763,0.121086,0.00001459,-11.26,-222.18
      4,986461,0.151573,0.00003318,-7.63,-211.67
      5,955766,0.160869,0.00005782,-4.07,-201.37
  </code></pre>
  
  <p>Basically i need to a way to tell gnuplot to ignore the first 3 rows and plot the 2rd and 3rd column.</p>