program to remove duplicates

i think if to write a simple comandline program
that remove duplicates in a given folder
i mean some should copy a program to given folder
run it and all duplicates and multiplicates (when
duplicate means a file with different name but
exact binary size and byte content) will be removed
leafting only one for multiplicate set
this should work for a big doze of files -
i need it for example i once recovered a hdd disk
and as i got some copies of files on this disc
the removed files are generally multiplicated
and consume a lot of disk space
so is there some approach i need to take to make this
proces faster?
probably i would need to read list of files and sizes in
current directory then sort or go thru the list and if found
exact size read it into ram tnen compare it byte by byte
in not sure if to do sorting as i need write it quick
also and maybe sorting will complicate a bit but not gives much
some thoughts?