How to use offset in getting the last 7 digit of a sting

Hi,

Will you please tell me, how I can use Offset like command for the following code :-

Data :- v_file type string .

Let v_file = xyz/abc/ABCD/pq.rs.tuv1234

I want to take last 7 digit i.e. "tuv1234"

Please tell me..

Saurabh