Why is my mv renaming for a directory not working?

Question

$ mv 'Assignments' 'assignments'
mv: cannot move `Assignments' to a subdirectory of itself, `assignments/Assignments'

Trying to rename Assignments directory to assignments

Answer 1

The OSX HFS+ filesystem is case-insensitive, so it's interpreting Assignments and assignments as the same name. I would try:

$ mv Assignments tempdir
$ mv tempdir assignments

Answer 2

you are working with a filesystem which is not case sensitive (though it is case preserving). So when you say mv Assignments assignments, it is as if you are saying mv Assignments Assignments/assignments. Instead try renaming it to something else first.

Answer 3

The nuclear option is to start from scratch on this hard drive partition and OS installation by enabling OS X's Mac OS Extended (Journaled, case-sensitive) option. Be aware that this requires a complete reformatting of the disk and will clobber everything on the affected partition.

Another caveat is that certain applications in OS X do not place nicely with case-sensitive file systems. (At the time of this writing, I believe Steam is one of them.)

I just wanted to make readers of this question aware that this option does exist.

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I personally resist the idea of the intermediary step and prefer to use the Finder to make such a change. It will not complain about the change if you rename the folder or file by just changing case.