To iterate all files, including in sub directories, use os.walk:

import os
for root, folders, files in os.walk(root_dir):
    for filename in files:
        print root, filename

root_dir can be “.” to start from current directory, or any other path to start from.

If you also wish to get information about the file, you may use the more efficient method os.scandir like so:

for entry in os.scandir(path):
   if not entry.name.startswith('.') and entry.is_file():
       print(entry.name)