hope not to confuse the questioner but in the case of external hard drives using thecommand is often the only thing to REALLY get rid of the trash on them. They simply make a directory /.Trash which you cannot remove in any way except for the rm command.Code:rm -r
However, when doing the rm command, as long as you don't giv eit super user privileges, it cannot harm your system, your personal files it may delete though, so still to be careful.
Its best to know what the rm command does with its several flags (the -r for example) so the -r means that all directories AND their contents will be removed, and the * option just means that ANY file or directory will be deleted. YOu cannot recover files removed with rm, so that why you need to be extra careful.