Command-line doomsday calculator.
Copyright 2022, 2023 ZCJ
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.
Written for Telehack
The doomsday algorithm was worked out by John Conway. It makes use of the fact that each year has specific dates that all fall on the same day of the week.
This day of the week changes based on the year, obviously, or the calendar would look rather dull. There's a skip of one day each year and a skip of two every leap year.
Once you figure out a year's doomsday, you can add and subtract to get to the wanted date. Neat shit.
pub /get zcj/doomsday.bas
Alternatively, you can ftp it over or copy it into ped.
$ doomsday --help
CLI Doomsday Calculator
Usage:
doomsday [iso date]
doomsday --timestamp <unix timestamp>
doomsday --for <year>
doomsday --anchor <year>
doomsday --format <date format> <date>
doomsday --today
doomsday --random
You may use a single hyphen, a double hyphen, a slash, or nothing at all to lead arguments.
$ doomsday 2018-08-15
15 August 2018 was on a Wednesday
$ doomsday 3000-04-12
12 April 3000 will be on a Saturday
$ doomsday for 1919
1919's doomsday was on a Friday
$ doomsday --timestamp 1676170892.09022
12 February 2023 was on a Sunday