Should directories be named in singular or plural? [closed]

Use plurals if there's even the possibility of there being multiple items in that directory (whether now, in the past, or in the future). If on your desk you had a box labelled "Pencils" which contained five pencils, and you took four out, you wouldn't suddenly decide that the "Pencils" label was incorrect and needed to be replaced with one that just said "Pencil". You'd just think that you were running out of pencils.

On the other hand, if there will never be more than one item in that directory, no matter what happens in the future, then it would probably be more intention-revealing to use a singular name. This doesn't happen that often, though, because if there's only ever going to be one item in a directory, you don't really need a directory (unless that "one item" is actually made up of several files).

On the whole, I would use pluralized names unless I had a very good reason to use a singular.