If your goal is to do this reliably, don't reinvent the wheel -- use rsync. It will quickly mirror directories for you. Sometimes this is already installed (e.g. some Linux boxes). Try "man rsync". If not, it's generally worth installing. See http://rsync.samba.org

If you don't want to use rsync, see if your 'cp' has a recursive option ('-r' or '-R'). GNU cp also has a '-u' flag that only updates files that have changed. You can use the '-p' flag to preserve file timestamps.

I'd suggest you avoid the tar solution. If something fails (like a 'cd') it can create a mess and it's not easy to detect errors with a shell pipeline.

If this is more of a learning experience and you want to try this in perl, you'll can learn from countless others who have tried doing this by using Super Search.

bluto