Add redirect_from to all Jekyll posts

redirect_jekyll_posts.py

from pathlib import Path

for file in Path('_posts').glob('*.md'):
    print(file.name)
    year = file.name[0:4]
    month = file.name[5:7]
    day = file.name[8:10]
    title = file.name[11:-3]
    oldurl = f'/{year}/{month}/{day}/{title}/'
    print(oldurl)
    content = file.read_text(encoding='utf-8').replace('---\ntitle:', f'---\nredirect_from: {oldurl}\ntitle:')
    file.write_text(content, encoding='utf-8')