Title : Birthday dates management using calendar
Author: Solène
Date  : 15 June 2020
Tags  : openbsd plaintext automation

I manage my birthday list so I don't forget about them in a
[calendar](https://man.openbsd.org/calendar.1) file so I can use
it in scripts

The calendar file format is easy but sadly it only works using
English month names.

This is an example file with differents spacing:

    7  August	This is 7 august birthday!
     8 August	This is 8 august birthday!
    16 August	This is 16 august birthday!

Now you have a calendar file you can use the **calendar** binary
on it and show incoming events in the next n days using -A flag.

    calendar -A 20

Note that the default file is `~/.calendar/calendar` so if you
use this file you don't need to use the `-f` flag in calendar.

Now, I also use it in crontab with xmessage to show a popup once a
day with incoming birthdays.

    30 13 * * *  calendar -A 7 -f ~/.calendar/birthday | grep . && calendar -A 7 -f ~/.calendar/birthdays | env DISPLAY=:0 xmessage -file -

You have to set the DISPLAY variable so it appear on the screen.

It's important to check if calendar will have any output before
calling xmessage to prevent having an empty window.