awk - show difference between two fields

Question

I have this:

bar foobar        
111 random111

I want to define $2 so that when compared to $1, it should contain only the differences (non-matching characters):

bar foo
111 random

Answer 1

To print the differences as jaypal points out:

awk '{gsub($1,"",$2)}1' file
bar foo
111 random