Please, if you have not done it, read the Debaday article. Thank you.
This article of debaday site, by Olivier Schwander, were posted at http://debaday.debian.net/2008/11/16/remind-a-text-based-agenda-and-todolist-manager/ on 16/11/2008.
There are lots of different tools for managing your time: Mozilla has a standalone solution: "Sunbird":http://www.mozilla.org/projects/calendar/sunbird/ and another one based on Thunderbird: "Lighting":http://www.mozilla.org/projects/calendar/lightning/, KDE has "Korganizer,":http://kontact.kde.org/ and Gnome has the young "gnome-agenda":http://code.google.com/p/gnome-agenda/ and the very popular "Evolution":http://projects.gnome.org/evolution/, and we must not forget the most famous web based tool: Google Calendar.
All these applications are based on a graphical user interface, and use either "iCalendar":http://en.wikipedia.org/wiki/ICalendar or the older "vCalendar":http://en.wikipedia.org/wiki/VCalendar#vCalendar_1.0 as the data formats.
What about people who prefer console based interfaces and want to edit the data with their favourite text editors? The best solution is "remind":http://www.roaringpenguin.com/products/remind: it uses an easy but powerful language for describing events. A simple example, this event happens every Tuesday at 13:00 and lasts one hour:
You always forget your appointments? Remind can help you:
It will begin to bother you one day before the date, and will display warnings two hours before, every five minutes. The language is really powerful, and is able to express arbitrary complex date calculations (first Monday of a month, excluding holidays, moon phases). To look at the events of the day, simply run:
Remind can import and export iCalendar files, and generate HTML and Postscript from your calendar. You can choose to have reminders sent by email, or showed by a pop-up window but you'll need to start remind with some special arguments for that, see the "Remind FAQ":http://wiki.43folders.com/index.php/Remind_FAQ#How_can_I_generate_popup_windows_to_warn_me_of_timed_reminders.3F at the "43folders wiki":http://wiki.43folders.com/index.php/Remind which has a lot of useful tips for remind.
You can also use it through user-friendly interfaces: "tkremind":http://packages.debian.org/tkremind, a Tk based front-end, but it hides some of the power from remind; and "wyrd":http://packages.debian.org/wyrd, a curses based interface which eases the editing of events and lets you use all of the power of remind.