Find duplicate words using sed

UNIX for Advanced & Expert Users
1

I have following statement and I want to find duplicate word using sed command. How is it possible?

"detect string and remove the duplicate string"

There could be many statements in a file and each line may have duplicate word.

Thanks!

2

Sometimes a good google is all you need...Here is a sample where
someone uses awk.

http://www.folkstalk.com/2012/09/remove-duplicate-strings-words-from.html