[GRASSLIST:5669] Reading cell values at specific positions without mouse

[Kenlo Nishida]

Dear GRASS users:

Simple problem but I have not solved yet:
Reading cell values at specific positions without mouse.

I have several raster datasets and I want to extract cell values
at some specific positions on the raster data. One solution is 
"d.what.rast", but it needs selection of the positions with a mouse.
Instead, I want to tell GRASS the positions with coordinate values
(latitude and longitude) from a text-file or standard I/O. 

Can you please tell me appropriate commands or procedure for it?

Kenlo Nishida
kenlo at sakura.cc.tsukuba.ac.jp