title: gnuplot to group multiple bars
body: <p>I am using gnuplot to generate graphs for multiple benchmarks.<br/> 
  For each benchmark I have many configurations to plot. 
  I want to plot a graph hit-rate(my y-axis) vs benchmark(x-axis). 
  There will be multiple columns for each benchmark differentiated by their color. </p>
  
  <p>I generated the same type of graphs some time back using some python script, but I don't know how to do this in gnuplot.</p>