How to search same file with different case

First, list all the files in alphabetical order

find . | tr [:lower:] [:upper:] | sort > ../sort.list

Second, list all the files in alphabetical order without duplicates

find . | tr [:lower:] [:upper:] | sort |uniq ../uniq.list

Third, run the diff to find same file with different case

diff ../sort.list ../uniq.list