Plotting continuous line in Gnuplot for frequency count

To get a line plot you can replace with boxes by with lines. However this is probably not the best way to display this sort of binned data. I suggest using the on-line demo bins.demas a guide. I copy it here for reference.

#
# Demo illustrating the relationship between
# a binned histogram and a kernel density model of the same data.
#
$DATA << EOD
1   1
2   1
8   1
9   1
17  1
17  1
9   1
9   1
5   1
7   1
7   1
8   1
8   1
8   1
10  1
11  1
11  1
12  1
14  1
3   1
3   1
3   1
8   7
15  1
17  1
17  1
18  1
19  1
20  1
EOD

set title "Comparison of a binned histogram and\na kernel density model of the same data"

set style data lines
set xtics 1 norangelimit nomirror
set grid y
set yrange [0:5.5]
set style fill solid 0.5 noborder
set jitter spread 0.5

plot $DATA using 1 bins=20 with boxes title '20 bins', \
        '' using 1:(1) smooth kdensity bandwidth .5 lw 2 title 'smooth kdensity', \
        '' using 1:(.9) with impulse lc "black" title 'jittered data'

Notes:

• bins=20 will automatically divide the data into 20 equal-width bins along x. There is an optional keyword binrange but if no binrange is given, the range is taken from the extremes of the x values found in the data.

• The set jitter command adds a small displacement to points, or in this case impulses, that would otherwise lie exactly on top of each other. It has no effect on the boxes or lines.

• smooth kdensity is one of many options for producing a smooth line. For full documentation see the gnuplot documentation. It generates a function f(x) in which each point in the data set acts as the center of a Gaussian weighted by distance from x; the resulting curve is the sum of these contributions. Selecting a bandwidth smaller than the spacing between points insures that each local maximum gets its own peak.

• Each of the three representations, boxes, lines, and impulses could be plotted independently. This plot combines all three modes for comparison.