The difference between Windows ".." and unixy ".." is that the former is done lexically whereas the latter is a link to the canonical parent.

E.g. on Windows: "path\to\..\file" is always the equivalent of "path\file". Whereas on unixy systems "path/to/../file" may take you to a completely different parent directory.

That said, Unix shells can muddy the waters a bit. They may choose to act lexically with some commands.