Your script is great but it doesn't answer my question.

I need to keep the exact uniq content I have in the original file:
(suppose That each line has a pssword which is case sensetive)

So if my input file1 contain:
DAVID, aaBBCC
don, abcDk
kevin
KEVIN
DON, aBcDk

When I activate your script, I get:
david aabbcc
(line case was change)

And this is not what I need, I except to have the exact uniq content:
DAVID, aaBBCC

Again, thank you very much for your efforts and I hope that I will finally have a solution for it.

Roy