> #8408 was proposing a new module, which seems a bit overkill

If a module seems overkill, then maybe add this useful function to os module. Don't leave it private to argparse module. Maybe something along these lines:

    >>> import os
    >>> print(os.get_terminal_size())
    (80, 25)

Why do I believe a module could be better? Because I'd also like some way to detect when the terminal size has changed (without probing it all the time).