Recursively optimize *.png files with ect (ect must already be on command line or adjacent to script)

ect.py

from pathlib import Path
import glob
import sys
import subprocess
from tqdm import tqdm
from multiprocessing import Pool

# https://github.com/shssoichiro/oxipng
def oxipng(path):
    subprocess.run(['oxipng', '-o', '4', '--strip', 'safe', path])

# https://github.com/fhanau/Efficient-Compression-Tool
def ect(path):
    subprocess.run(['ect', '-9', path])

# Progress bar only works when num_processes = 1
if __name__ == '__main__':
    # Converting to a list with a huge number of files may be problematic
    # but it's an easy way to get tqdm to properly display a progress bar
    paths = list(Path(sys.argv[1]).rglob('**/*.png'))

    num_processes = 1

    if num_processes == 1:
        for path in tqdm(paths):
            print(path)
            ect(path)
    else:
        with Pool(num_processes) as p:
            p.map(ect, paths)
        print(f"Finished processing {len(paths)} files")