# Example usage:
cat checksum_list_1 checksum_list_2 | sort | uniq -c | sort | less
# This command concatenates the lists, sorts them so that repeated
# checksums are adjactent, adds the count of each, and then sorts them
# again so that highers counts are at the bottom. Normally, when 
# transferring files from A to B, you expect a count of two for each
# file. Counts of one indicate unique md5sums which probably mean there
# was an issue in the transfer