set file date based on the pattern in the filename

setfdate.py

#! /usr/bin/env python3

"""
set file atime and ctime based on the date pattern YYYY[_-]MM[_-]DD in filename
"""

import argparse
import re
import os
import datetime

parser = argparse.ArgumentParser()
parser.add_argument("files", nargs='+')
args = parser.parse_args()

for file in args.files:
    m = re.search(r'(20[012]\d)[_\-]?(\d\d)[_\-]?(\d\d)', file)
    if m:
        y, m, d = map(int, m.groups())
        t = datetime.datetime(y, m, d, 12)
        os.utime(file, (t.timestamp(), t.timestamp()))
        print("{:80} {}".format(file, t.strftime("%Y-%m-%d")))