Python：在 Unix（Fedora）系统上运行带有 'ls' 子进程的脚本时，argparse '错误：无法识别的参数'

Question

I encountered error: unrecognized arguments when trying to run my Python script in Fedora's Terminal. (It worked fine in Windows Shell.) I stripped it to absolute barebone version but the same error still persists.

import subprocess
from argparse import ArgumentParser

def print_filenames(directory):
    try:
        ls_output = subprocess.run(["ls", "-a", directory], shell=True, capture_output=True, text=True)
        ls_output.check_returncode()
        ls_output_str = ls_output.stdout
        ls_output_list = ls_output_str[:-1].split("\n")
        list_of_files = []
        for file in ls_output_list:
            list_of_files(file)
        return list_of_files
    except subprocess.CalledProcessError:
        # Same process but with dir /b command (for Windows)
        pass

if __name__ == '__main__':
    parser = ArgumentParser(prefix_chars='-', usage='Some usage', description='Description')
    parser.add_argument('directory', metavar='directory', type=str, help='str, required: directory')
    args = parser.parse_args()
    input_directory = args.directory

    print(get_filenames(input_directory))

Running script in terminal with expected output:

$ python myscript.py ./this_folder/*.xml

['./this_folder/first_file.xml', './this_folder/second_file.xml', './this_folder/third_file.xml']

Actual output:

$ python myscript.py ./this_folder/*.xml

usage: Some usage
myscript.py: error: unrecognized arguments: ./this_folder/first_file.xml ./this_folder/second_file.xml ./this_folder/third_file.xml

Any idea what might be causing the problem? Why does my subprocess output appears as 'unrecognized arguments'?

Answer 1

After some trial-and-error, I found out the solution to this. Instead of running subprocess like this:

subprocess.run(["ls", "-a", directory], shell=True, capture_output=True, text=True)

I ran it like this (with entire command in an f-string):

subprocess.run([f"ls a {directory}"], shell=True, capture_output=True, text=True)

and it does exactly what it is supposed to do.

I don't have clear understanding of the problem so any help would be appreciated. My guess is that without putting entire command into a single (f-)string, subprocess runs just ls and ignores directory stated behind it. At least that's what it seems to do.