Most old-school shutdown init scripts called the following at some point before shutting down or rebooting: kill -TERM -1 # sending all processes the TERM s

Most old-school shutdown init scripts called the following at some point before shutting down or rebooting: kill -TERM -1 # sending all processes the TERM signal... # ... sleep $SOME_SECS # ... kill -9 -1 # sending all processes the KILL signal... # ... sleep $SOME_MORE_SECS Also old-school local DoS from root: # used to be very bad rm -rf / ; kill -9 -1 Another classic: # bash fork bomb :(){ :|:& };: # creates a function : and calls it # spawns a background process that pipes to itself, which creates another process... effectively two recursive calls per call.