Excluded characters in file names

I use a lot of Korean characdters in file names, which are stored as text files.
With Korean files names in text files the characters become uhmm disjointed.
This definitely happens on Windows.
For instance ? becomes ???, and of course that won’t do.
So, I need to change the file extension from file names. i do this by changing the “.” to an illegal character.

On Windows and Mac that character seems to “:”

Apparently the “?” is used for Linux, but I’m not sure
Can anyone verify this, or a different character.

google is your friend here


there are others like the wikipedia article