I often want to know who there is a sudden growth disk usage over the last month/week/etc, what suddenly take space. In those cases I find myself wishing that du and friends would cache their last few runs and would offer a diff against them, this easily listing the new disk eating files or directories. Could dut evolve to do something like that?
Almost all of them will have some difference. What is needed is to parse the previous state, calculate the difference in size, and show only the "significant" difference.
btdu extra (or expert?) mode with snapshots kinda does that: you can see what's only in the new version and not in a snapshot; and vice-versa.
Also it offers attributing size to folders only for extends that aren't shared with a different folder (snapshots are essentially just special folders), to kinda get a diff between the two (stuff only present in the old snapshot is shown there; stuff only present in the new version is shown there).
