Once dates get too complex it is easier to just have an external script figure out whether today is the day and have it run every day: 0 9 * * * anvandare is

Once dates get too complex it is easier to just have an external script figure out whether today is the day and have it run every day: 0 9 * * * anvandare is-today-the-day.py && celebrate.sh With is-today-the-day.py being: #!/usr/bin/env python3 import sys from dateutil.easter import easter from datetime import datetime as dt today = dt.today().date() (easter(2023) - today).days == 0 and sys.exit(0) or sys.exit(1) Or, if we didn't have the easter function already (just adding this because it was fun to work it out): #!/usr/bin/env python3 import sys, ephem as e, datetime as dt setup = '2022/09/25' date = (e.next_full_moon(e.next_equinox(setup))).datetime() easter2023 = (date + dt.timedelta(7 - date.isoweekday())).date() today = dt.datetime.today().date() (easter2023 - today).days == 0 and sys.exit(0) or sys.exit(1)