Prune - Find's tricky switch

After many thousands of uses, I finally got around to investigating find's exclusion parameters.  Showing its age, it basically consists of an arcane string of -path options combined with an -o for "or" followed by a -prune to indicate the need to exclude it from the search.

I was always sure there was some way to do it.  (With a regex, if nothing else.)  I've read the man page about 100 times and I've never understood how it worked till last week.  It works like a charm, in fact.

That being said, surely something closer to the du --exclude parameter is in order.  Features aren't very useful if people don't know they're there.

ctime vs mtime

So about that huge file cleanup . . .  it seems that Netapp's ndmpcopy resets all the files' ctimes.  (Meaning there were changes to the inodes somewhere in the process).  Fortunately, the mtimes were preserved so I was able to generate a proper distribution-over-time stat.

I can only assume (since the guy who ran the ndmpcopy swears he didn't do anything else), that that means ndmpcopy is actually creating the inodes on the fly rather copying the existing ones over.  Good to know.  (rsync preserves those stamps the way I usually run it, so I've never run into this issue before.)