Python Progress-bar while downloading files using linux terminal

progress-bar.py

#!/usr/bin/python3

import os
import sys
import time
import urllib.request


def show_progress(block_number, block_size, total_size):
    global start_time
    if total_size < 0 or None:
        return
    if block_number == 0:
        start_time = time.time()
        return
    duration = time.time() - start_time
    progress_size = min(block_number * block_size, total_size)
    speed = int(progress_size / (1024 * duration))
    percent = min(int(block_number * block_size * 100 / total_size), 100)
    sys.stdout.write("\r[{}{}] {}%, {} KB/s, Downloaded {:.3f}/{:.3f} MB in {:.3f} seconds   ".format(
        '#' * (percent // 5), '.' * (20 - percent // 5), percent, speed, progress_size / (1024*1024),
        total_size / (1024 * 1024), duration))
    sys.stdout.flush()


if __name__ == '__main__':
    try:
        url = sys.argv[1]
    except IndexError as e:
        print(e, "#usage: python3 progress-bar.py url")

    file_extension = list(url.split('/'))[-1]
    file_path = os.path.join(os.getcwd(), file_extension)
    print("Downloading {} to {}".format(url, file_path))
    urllib.request.urlretrieve(url, file_path, show_progress)
    print()