How do I draw a set of vertical lines in gnuplot?

Question

E.g. if I have a graph and want to add vertical lines at every 10 units along the X-axis.

Accepted Answer

Here is a snippet from my perl script to do this:

```
print OUTPUT "set arrow from $x1,$y1 to $x1,$y2 nohead lc rgb \'red\'
";
```

As you might guess from above, it's actually drawn as a "headless" arrow.

Solution