I'm moving large amounts of data from one external drive to another larger one. The files are important and the smaller drives need to be cleared and reused (HD camera). Is there some utility for moving files and verifying their integrity?

I've been using this command

find . -type f -exec md5 '{}' \; > md5list.txt

in the terminal to create a list of MD5s for each file then using diff to compare the two. However, I am moving 320GB at a time, which takes a while by itself. Computing the checksums takes another hour or so. It would be much more efficient to do this on the fly, during the copy. I'm just hoping someone has already written the software...