You first have to tell Gnuplot to use a style that uses points, e.g. with points
or with linespoints
. Try for example:
plot sin(x) with points
Output:
Now try:
plot sin(x) with points pointtype 5
Output:
You may also want to look at the output from the test
command which shows you the capabilities of the current terminal. Here are the capabilities for my pngairo terminal: