GNUPLOT

To plot CSV files do the following,
set datafile separator ","

to print to eps:
set terminal postscript eps enhanced "Times-Roman" 18
set size 1.0, 1.0
set output 'histo.eps'

Here, size is relative to the box

to generate histograms:
(actually gnuplot cannot cumulate the data for you.
use a program to do that. gnuplot only draws the bar chart)

set style fill solid 1.00 border -1
set style data histograms
set style histogram clustered gap 1
set xtics border in scale 1,1 nomirror rotate by -45 offset character 0, 0, 0

set xlabel "xxx"
set ylabel "yyy"
set yrange [0.00:1.00] noreverse nowriteback
set nokey #off the legend
plot 'datafile' using 2:xticlabels(1) #column one contains labels
pause -1 #wait until enter is pressed