[anvandare]

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)