ical is an old but popular calendar package written in Tcl/tk by Sanjay Ghemawat for Unix

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 systems. ical is known for its simple, intuitive interface. It's also easy for Tcl/tk programmers to extend ical with custom functionality. It stores all calendaring information in a single flat text file per user that may be easily parsed by perl

Perl

Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...

 or python

Python (programming language)

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...

 scripts.

ical is not related to the iCalendar

ICalendar

iCalendar is a computer file format which allows Internet users to send meeting requests and tasks to other Internet users, via email, or sharing files with an extension of .ics...

 format standard, and does not utilize it. It is also not related to Apple Inc.'s calendaring application, confusingly called iCal

ICal

iCal is a personal calendar application made by Apple Inc. that runs on the Mac OS X operating system. iCal was the first calendar application for Mac OS X to offer support for multiple calendars and the ability to publish/subscribe calendars to WebDAV server....

.

External links

• ical maintenance project
• ical development project