s3-list.py

import boto3


s3_paginator = boto3.client('s3').get_paginator('list_objects_v2')

def keys(bucket, prefix='/', delimiter='/', start_after=''):
    prefix = prefix[1:] if prefix.startswith(delimiter) else prefix
    start_after = (start_after or prefix) if prefix.endswith(delimiter) else start_after
    for page in s3_paginator.paginate(Bucket=bucket, Prefix=prefix, StartAfter=start_after):
        for content in page.get('Contents', ()):
            yield content['Key']

list_files = keys(bucket=BUCKET_NAME, prefix=PREFIX)
fh = open('index', 'w')
for i in (list_files):
    i = i.replace('PREFIX', '')
    fh.write(f'{i}\n')
fh.close()