the slash (/) after a directory name on shell commands

I have a little question here. If I have two files, say filea and fileb, mv filea fileb would - delete fileb - rename filea to fileb Then if I have two directories, say dira and dirb, mv dira dirb would - move dira into dirb (it will become dirb/dira) Noting that in both cases there are no notice or message, then this is pretty inconsistent to me. I think mv dira dirb should just overwrite dirb with the contents of dira (or merge the two directories under a directory named dirb). I remember reading somewhere that a directory name with a slash (like dira/) is treated like a directory, and name with no slash (like dira) is treated like a file (to certain extents, of course). Anyway now I want to make the shell (zsh and possibly bash) respect my notation of a directory by using a slash. Is there a terminal option which enable me to enforce that? To clarify, here is my desired behaviour: - mv dira dirb results in dirb being overwritten with the contents of dira - mv dira dirb/ results in dira being moved into dirb (in dirb/dira) Has anyone thought the same way as me? Or am I just weird?