Пример построения гистограммы в gnuplot

reset

## intervals
n = 10              # number of intervals
max = 10.           # max value
min = 0.            # min value
width = (max-min)/n # interval width

## function used to map a value to the intervals
hist(x,width) = width*floor(x/width)+width/2.0

## output terminal
set term wxt persist # keep window open

## ranges
set xrange [min:max]
set yrange [0:]

## tics and labels
set xtics min,(max-min)/5,max
set boxwidth width*0.9
set style fill solid 0.5 #fillstyle
set tics out nomirror
set xlabel "x"
set ylabel "Frequency"

## calc and plot
plot "data.dat" u (hist($1,width)):(1.0) smooth freq w boxes lc rgb"green" notitle