I was going to post a similar response, but figured the writer knows what his scripts are for. But since you brought it up, my point was going to be, he never checks the veracity of the existing md5sums as he passes thru them. He checks if there is an existing md5sum for a file, then moves on, happily thinking his data has not been tampered with. What if the md5sum for that file has changed, or the file has changed?

I was giving him the benefit of the doubt thinking, "if he keeps daily backups of everything", he can always go back and find a day where the md5sum and data matched; but now I'm not so sure.

At least he should keep an md5sum of the file containing the md5sums, to be certain his script (or other force) has not screwed up his file.

The checking and double-checking never ends with "spy vs. spy", especially if your job is on the line if the data fails. Of course blaming it on cosmic rays usually fools the dumbos in management. :-)