gnuplot reading from data to plot bar chars

gnuplot reading from data to plot bar chars

I have a file with two columns
9 5
10 3
11 0
12 25
13 50
14 80
etc
What is the best way to plot bar char using gnuplot? Is using subprocess
with gnuplot the best way? Ideally the graph should be in .pdf and in png
as I want to put these on a website later on.
I would really appreciate your input/advise.