bbf (bad block finder)

bbf is a safer and more featureful tool for dealing with bad blocks
on hard drives. It's built around the workflow of dealing with hard
drive bad blocks. It has a number of features to limit risk in using
the tool and provides features to more easily track down what files
are affected by the bad blocks found. It also gives you the ability
to manually mark blocks as corrupted in cases where a block isn't
technically bad, but is causing issues.
