For some weird reason, I tried "'" as word separator in identifiers, as in:
$ export foo'bar=1 > > ^C $
The result is as shown above, id est the prompt changes to ">" and the system obviously waits for more information on my part. As you see, I had to ctrl-C to escape. The same happens using other commands such as
$ ls foo'bar $ mkdir foo'bar
I'm curious about the sense of all this, that is what special meaning "'" has in terminal commands (so special in fact that it is taken apart even inside ids).
Extra: As an aside I would also like to know the set of special or otherwise invalid characters in file and folder names, both under Unix-like and Windows systems (to get the common subset of safe ones) (in particular, what about all non-ASCII?).
Thank you, Denis