How do I remove duplicate characters and keep the unique one only in Perl?

Question

How do I remove duplicate characters and keep the unique one only. For example, my input is:

EFUAHUU
UUUEUUUUH
UJUJHHACDEFUCU

Expected out

Answer 1

If the set of characters that can be encountered is restricted, e.g. only letters, then the easiest solution will be with tr
perl -p -e 'tr/a-zA-Z/a-zA-Z/s'
It will replace all the letters by themselves, leaving other characters unaffected and /s modifier will squeeze repeated occurrences of the same character (after replacement), thus removing duplicates

Me bad - it removes only adjoining appearances. Disregard