remind

sophisticated calendar and alarm program
Remind allows you to remind yourself of upcoming events and
appointments. Each reminder or alarm can consist of a message sent
to standard output, or a program to be executed.
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It also features: sophisticated date calculation, moon phases,
sunrise/sunset, Hebrew calendar, alarms, PostScript output, tcl/tk
front-end and proper handling of holidays.
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Reminders can be created by the remind scripting language or by using
the graphical frontend package "tkremind".