How to download and try this example
Usage: pl -gif curvefit0.htm
// Read data from curve2.dat #proc getdata file: curve2.dat #proc areadef rectangle: 1 1 2.5 1.7 xrange: 330 350 yrange: 70 120 // Do the green grid lines.. #proc yaxis ticincrement: 10 grid: color=green tics: none // Do the red line.. #proc lineplot xfield: 1 yfield: 2 linedetails: color=red // Compute a moving average curve and display it in blue.. #proc curvefit xfield: 1 yfield: 2 order: 20 linedetails: color=blue