[GRASSLIST:4344] applying raster heightmap to vector file z value

[Benjamin Mesing]

Hello,

I have a heightmap for an area as a rasterfile. I also have a vector file 
without z-information. Now I would like to use the height information of the 
rasterfile to apply it to the z-coordinate of the vectors in the vector map.
How can I do this with grass (I have 5.3 and 5.7 at hand)?
I have already taken a look at v.what.rast but first I was not able to launch 
it as I do not know what to enter in the column field and second it would 
store the height as an additional attribute what is not what I want.
Please note that I am a complete newbie to grass and GIS in general.

Thanks for your help.

Greetings Ben