[Serusers] General Question on avp_subst

[Mike Trest - Personal]

Hi,
I am confused by documentation with foo bar examples.

Can someone please give me a clear ser.cfg example of avp_subst that 
really works
in your running ser.cfg?

preferably one that works on and avp  called $revision  to substitute
a substring of numbers (8831)  with another set of numbers (5431)
where the target digits are surrounded by other stuff.

..mike..
.