if there are lots of big files e.g. file>1GB then you have some problems..
though if they are small files perhaps this code might help you. it first checks the exact size and if the sizes match then it continues to check md5sums ... ... prob is it only finds them,,
Code:
find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate
also this is a script check it out
http://www.unix.com/shell-programmin...od-enough.html this guy already did the script
EDIT: and also if you are interested in more there are more results in the google search i made
http://www.google.com/search?ie=UTF-...ased+on+md5sum