Controlling vertical line lengths in Tools - Line - Vertical: Limitations via Command Line

Using Tools - Line - Vertical creates a short vertical line at the chosen point,
but I am unable to control its length through the Command Line.

from command line, it's convenient to use "2 points"

for example, after the first point, use command line: @0, 10

Heime wrote

Using Tools - Line - Vertical creates a short vertical line at the chosen point,
but I am unable to control its length through the Command Line.

What is utility of Vertical and Horizontal though?  They seem to make
only fixed length lines.

Look at the tools options bar above the drawing area. It's contents change according to the tool in use.