I'm trying to copy the content of a flash drive to my mac box. the content originally came from win and the flash drive is formatted in FAT. I'm concerned that not all content was copied successfully. I did not find a way to right click on the flash drive and count the number of items (it works on a directory but not on the flash drive). my goal is to validate that the content of the flash drive is identical to the content on the mac. is there a way to validate the copy? is there a way to validate via checksum on a file tree recursively and compare both source(flash drive) and target(mac)?