Do automatic post-processing by doing the following:
(this example uses time step 1200. To use another time step
modify the -time for sample, and modify in compareAll.gplt)

sample -case .. -time 1200
gnuplot compareAll.gplt
mozilla file://$PWD/compareAll.html

To plot the residuals do the following:
(This example assumes that you have a log file in your case directory)
foamLog ../log
gnuplot plotResiduals.gplt
mozilla file://$PWD/residuals.png

The development of these files was done by:
Håkan Nilsson, Chalmers University of Technology, Sweden
Maryse Page, IREQ, Hydro Quebec, Canada
Martin Beaudoin, IREQ, Hydro Quebec, Canada
Omar Bounous, Chalmers University of Technology, Sweden