In your above example %3,7i[0-9a-f] % is wild 3,7i[0-9a-f] = anything from the second char through the 7th can be 0123456789 abcdefABCDEF. But I am having a hard time understanding how to exclude any digits other than the last two or four AND [0-9a-f] looks like I want only letters a-f. Dont I want it to be [0-9a-z]? or is "f" just a symbol that means a-z?
My mistake, yes.
a-f means from a to f.
a-z is what i intended to write.
So If I wanted to exclude all digits (and special) other than the last four I could write %3,7i[a-f]?
%3,7i[a-z], yes.