Would running (rm deliberately broken)
sudo r m -rf /
Wipe out any USB-attached external hard drives being used for time machine backups?
It might do that much damage - but it isn't a good area for experimentation.
I have seen a machine crippled because someone executed '
The answer is not completely simple. For a start, you can't remove the mount points of directories leading to them. However, anything underneath a mount point (such as your Time Machine backups) could be removed if the system keeps running long enough. Secondly, it is hard to review what's left over afterwards; there aren't any commands left to let you do much. You'd have to boot off a CD of some sort and then inspect the residue. Thirdly, MacOS X has some settings which prevent even root from modifying some things sometimes - until you've adjusted the extended attributes etc.
But it will do a lot of damage. And you are advised not to try it on a machine where you care about the data on any of the attached disks. Unmount and detach the disks first - at least.
AFAIK when you specify -r with rm it works from the bottom of the hierarchy up, so that the contents of the drives would go before their mount point was deleted.