23 - Plotting the last/first "N" lines of a data file within gnuplot

If we are interested in the last/first N lines of a data file and we would like to plot those, the needed
command in gnuplot is

> pl "< tail -N filename" u 1:2 w lp
which plots the last N lines,
or
> pl "< head -N filename" u 1:2 w lp
that plots the first N lines.