Technically, on linux, this will not work across mount points even if the filesystems are the same.

@Stebalien by "filesystems are the same", is ext4 an example of a filesystem?

Filesystem as used in this comment (i.e. partition?)

In that you can have multiple mount points in the same partition?

I believe that depends on the filesystem. The trivial example is bind mount which lets you mount a directory:

mkdir /path/to/a
mkdir /path/to/b
mount -o bind /path/to/a /path/to/b

These both have the same filesystem (the directory /path/to/a) but different mount points. See the EXDEV comment in man 2 rename (on linux).

Yeah, filesystem is rather ambiguous. Maybe @steveklabnik should simply say mount point?

In this case, filesystem is incorrect on linux (both interpretations) HOWEVER, on reading the windows spec, I get the impression that you can rename files between mount points (you can mount drives in folders: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365733%28v=vs.85%29.aspx) as long as they refer to the same underlying filesystem (partition).

wow, impressive :)