r.watershed command

-- [ From: Ezzeddine sdiri * EMC.Ver #2.5.02 ] --

Dear GRASS Users
I have to use the program r.watershed in my work (Thesis). I don't have a
clear idea about this command, can anyone from you help my by explaining the
inputs and the outputs of r.watershed program using an example?
Thanks in advance

Ezzeddine sdiri
E-mail: sdiri@www.maich.gr