Expanding wildcards in shells of Windows using the dir or the ls commands

win_wildcard.py

# **DEPLICATED** the updated version is available at https://github.com/tos-kamiya/win_wildcard

# ref: https://stackoverflow.com/questions/55597797/detect-whether-current-shell-is-powershell-in-python

from typing import List, Optional
import locale
import os
import psutil
import re
import subprocess


SUBPROCESS_OUT_ENCODING = locale.getpreferredencoding()


def get_windows_shell() -> Optional[str]:
    # Get the parent process name.
    pprocName = psutil.Process(os.getppid()).name()

    if re.fullmatch('pwsh|pwsh.exe|powershell.exe', pprocName):
        return 'powershell'

    if re.fullmatch('cmd.exe', pprocName):
        return 'cmd'

    return None


def expand_wildcard(filename: str) -> List[str]:
    if not (filename.find('*') >= 0 or filename.find('?') >= 0):
        return [filename]

    s = get_windows_shell()
    if s == 'powershell':
        # Get-ChildItem -File -Name *.txt  # option `-File` to match only files, no dirs.
        out = subprocess.check_output(['powershell.exe', '-Command', 'Get-ChildItem', '-File', '-Name', filename])
    elif s == 'cmd':
        # dir /A-D /B *.txt  # option `/A-D` to match only files, no dirs.
        out = subprocess.check_output(['dir', '/A-D', '/B', filename], shell=True)
    else:
        return [filename]

    text = out.decode(SUBPROCESS_OUT_ENCODING)
    r = []
    for L in text.split('\n'):
        if L:
            r.append(L)
    return r


if __name__ == '__main__':
    import sys

    if get_windows_shell() is None:
        sys.exit('script executed outside of Windows cmd.exe or powershell')

    files = []
    for a in sys.argv[1:]:
        r = expand_wildcard(a)
        files.extend(r)

    print('\n'.join(files))

The Windows shell leaves wildcard expansion to the command, so there is no standard way to expand wildcards.
At first, I thought the Win32API FindFirstFile and its Ex equivalents might be official, but these functions are designed to treat < and > as special characters, which is different from the shell's specification, so they were rejected.
Next, I thought it would be better to use the shell's dir or Get-ChildItem command to expand the file so that the user can check the expansion result, but it requires checking the current shell.
That's how I ended up with this. I've been surprised to figure out that such a basic function is hard to implement.