Sorry, another Mac post. Please skip over this if you’re not interested – things will return to a normal level once the novelty has worn off, I promise. 🙂
On OS X, make a file. Doesn’t matter what, just type some random stuff into TextEdit and save it as test.rtf in your home folder. Now load the terminal up:
$ mv test.rtf test:file.rtf
Now look in the Finder. It will be called test/file.rtf. But that’s not what we called it!!
HFS+ (the filesystem) uses colons (:) as directory separators, but Unix uses the forward slash (/). The Unix underneath OS X can’t handle a file with a / in the name, but HFS+ can’t handle a file with a : in the name.
So Mac OS X swaps them around when necessary.