Gnuplot script, for loop within or adding to existing plot.

Question

Hello,

I would like to plot a series of vertical lines in gnuplot at a set interval.

Some information about the plot.

The plot is mainly some data from a .dat file. The gnuplot script is called by a bash scripts which alters the gnu plot script using sed. This is a snipit of the an old bash script (ugly I'm sure).

sed -i 's/C = CONCEHOLD/C = '${$CO}'/g' $GNUPLOTROOT/plotviscosity.plt
gnuplot $GNUPLOTROOT/plotviscosity.plt
mv my-plot.ps $VISCPLOTNAME
sed -i 's/C = '${$CO}'/C = CONCEHOLD/g' $GNUPLOTROOT/plotviscosity.plt

with the . plt file looking like this.

set title "Viscosity vs Time, C = CONCEHOLD, beta = RATHOLD, zeta = ZETAHOLD"
set xlabel "Time"
set ylabel "Viscosity"
plot "viscout.dat" using 3:2 title 'Viscosity'
# Saving to my-plot.ps
load save.plt
#

I would like to add to this plot a series of vertical lines at a set repeating interval. I have found how to plot vertical lines via http://t16web.lanl.gov/Kawano/gnuplot/parametric-e.html

set parametric
const=3
set trange [1:4]
set xrange [0:5]
set yrange [0:5]
plot const,t

I would like to have

const=repititionperiod*i

where i is an integer belonging to (1,calculateduppedlimit].

I could input repititionperiod via sed again and in a similar vain calculateduppedlimit but need some sort of for loop either within gnuplot or a separate gnuplot script that adds a vertical line to the already created plot within a for loop in my bash script.

I can't find any information on loops within gnu plot or adding to a previously created plot.

Any advice gratefully received.