Thanks a lot for your reply! I realized I didnt need to read each file in subdirectory and I edited my code based on your and other suggestion. Your code and my edited code generates list file within each subdirectory, but I am facing one issue. The array (@subdirs) creates a key for the main directory (here ./rootdir) as well. How can I ignore reading this directory in array and just read the subdirectories using File::Find? Thanks a lot!