[GRASS-user] Command to summarize the frequency distribution table

[SGW00412 at nifty.com]

Dear all

I'm a beginner grass user.

I made the raster map of altitude from GTOP30.

So, I want to obtain a frequency distribution table in the altitude.

For instance:

-------------------------------
height calls  number of cells
-------------------------------
0  -  10 m       100
11 -  20 m       200
21 -  30 m        50
........         xxx
------------------------------

But I do not understand what kind of commands to use. 

Please teach me the making method.

Regards, Yasuo from Japan.