Problem: I have a directory(D1) with 10000 files. I have a new data directory(D2) with 5000 files, of which most have the same file names as in D1. I want to copy any new files from D2 to D1. I want to overwrite files of the same name in D1 from D2 only if the new file in D2 is larger then the old file in D1. If the same name file in D1 is larger then the same name file in D2 then not to do the overwrite. Oh, and D1 & D2 have sub-directories with the same criteria. (I hope this is clear?) How to write a copy command that will do this?

Now now, KLund1, it sounds like you are expecting Windows to be some sort of System for Operating your computer! You will need third party software in order to accomplish a 'complex' task like this. I can't think of any that would do specifically what you're asking but I know programs like Unstoppable Copier and TeraCopy provide superior 'always overwrite if X' functionality so check these out to start with. If you buy three cars and the same wheel falls off all three, do you contact the person who sold you the cars or the person who made them?

I believe this can be accomplished with robocopy.exe

try muCommander, it's freeware but you must have JRE installed on your system

Hi, I think you can try the following tools. They can also perform comparisons during copying: RichCopy Robocopy Hope this helps. Thanks. Nicholas Li - MSFT Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.