Sorry if i cannot make use s/// but unique/duplicate call for hashes in my mind

# warning win32 doublequote

perl -e "print grep {$res{$_}==1} map {++$res{$_};$_} split '',$ARGV[0
+]" abcdefghiaabccdjklm
efghijklm
[download]

PS sorry if i've not seen this is identical in the approach to the toolic's one

L*