Hi, Just say I have a lot of files within directory A and directory B [main directory] and within directory A and B, it has plenty of two or three subdirectory. Can I use perl to automatically compare each of the files within directory A and its subdirectory which have same file names in the directory B and its subdirectory, in terms of something like sdiff in unix command and save it into each individual sdiff file plus a log file contains the directory and files in A sdiff to which file and directory in B? Thank you & best regards, ABC