Extract the first page of every PDF file in a folder structure to JPG

#! /usr/bin/env python
# -*- coding: utf-8 -*-
""" install pdftoppm first (use your package manager) """
import os

def main(start="."):
    for dirpath, dirnames, filenames in os.walk(start):
        for filename in filenames:
            if filename.endswith('pdf') and not filename.startswith('.') and f'{filename}.jpg' not in filenames:
                os.system(f'pdftoppm -jpeg -f 1 -l 1 "{dirpath}/{filename}" > "{dirpath}/{filename}.jpg"')
                print(f"Done {dirpath}/{filename}")


if __name__ == "__main__":
    main()