Non-unicode file names

[Cameron Simpson]

On 09Aug2018 03:14, MRAB <python at mrabarnett.plus.com> wrote:
[...]
>>>Is it true that Unix filenames can contain control characters, e.g. \x07?

Yep. They're just byte strings. You can't have \0 (NUL) because the API uses 
NUL terminated strings, and you can't use slash '/' in the filename components 
because that is the component separator. But otherwise you can basicly use 
anything - the OS itself doesn't care.

There are some (platform dependent) length limits, and the underlying mounted 
filesystem you're accessing may itself have special rules (eg nonUNIX 
filesystems like FAT32, etc).

>>>When happens when you print them out?

They get written out? If you're printing to a terminal of some kind then it 
will do whatever the bytes from the filename tell it to, as that's what 
terminals do.

>>>>>import sys; import subprocess
>>>>>subprocess.call([sys.executable, '\x07.py'])
>>.py
>>0
>>>>>
>>
>>As you might expect, it beeped when printing '\x07.py' (and showed .py)
>>
>And that's OK, is it? :-)

Of course it is :-) \07 is the ASCII BEL character, so it rings the terminal's 
bell.  Modern software terminals emulate that to a better or worse degree.

Suppose you're verbally reciting a filename (or, of course, printing the 
filename to a voder). Only Victor Borge will provide a full verbal 
pronunciation of things [1]

[1] https://www.youtube.com/results?search_query=victor+gorge+phonetic+punctuation

Cheers,
Cameron Simpson <cs at cskk.id.au>