I still use sar occasionally, but never as a troubleshooting tool. It's more for performance analysis than crisis mode.
Rarely need these under Linux but would have frequent use for such a tool under Windows with its mandatory file locking. "No you can't rename that directory but I won't tell you because fuck you."
TIL fuser. Thanks!
Welcome :)
Some HN monkeyboy has nothing better to do with his time than downvote a polite reply to a thanks.