In my previous seven articles in this series about systemd, and especially in the most recent article, time and date have come up in multiple contexts. systemd uses calendar time, specifying one or more moments in time to trigger events (such as a backup program), as well as timestamped entries in the journal. It can also use timespans, which define the amount of time between two events but are not directly tied to specific calendar times.

CardDavMATE is an open source CardDAV web client implementation released under GNU AGPL (version 3.0).

Curses front-end for Remind written in OCaml with vertically scrollable time table.

Calendar program for Unix/Linux systems that can keep track of events; custom, plain text storage format; interesting and fully functional.

CLI and terminal calendar program, able to synchronize with CalDAV servers through vdirsyncer.

CLI program to access Google Calendars; allows to do the main tasks: create, delete, and list events.

A tool for personal scheduling of appointments. Based on google calendar.

Calendar program for Unix/Linux systems that can keep track of events; custom, plain text storage format; interesting and fully functional.

Open source JavaScript jQuery plugin for a full-sized, drag & drop event calendar