Gnuplot

Here is an example how to visualize vmstat's output using gnuplot.

vmstat 1 10 | grep -v r > vmstat.txt
gnuplot -p -e "plot 'vmstat.txt' using 4 title 'free mem' with lines, 'vmstat.txt' using 5 title 'buffers' with lines, 'vmstat.txt' using 6 title 'caches' with lines"