IDATE(1) User Commands IDATE(1)
NAME
ical - A Hijri/Islamic calendar (and converter)
SYNOPSIS
ical [--gregorian yyyymmdd] [--hijri yyyymmdd] [--umm_alqura]
[--fixed_view] [--dual] [--help]
DESCRIPTION
The ical program is a Hijri/Islamic calendar displayer. It utilizes and
includes a Gregorian to Hijri (and vice-versa) date converter. The ap-
plication uses and offers multiple calculation methods with not all of
them agreeing at all times. The reason for this multiplicity is due to
not having one agreed upon method and so various entities develop and
advocate their calculations.
ical is able to comprehend and calculate both pre-epoch or pre-Hijrah,
denoted as "B.H", as well as post-epoch or post-Hijrah, denoted as
"A.H", dates. ical also utilizes Gregorian's pre-epoch "B.C" and post-
epoch "A.D" dates and notes them per its output. When entering pre-
epoch years, negative numbers ought to be utilized.
ical when run without any command-line options uses the host machine's
Gregorian date and converts it to Hijri to display that month's view.
Entries enclosed by [] denote exact day specified.
OPTIONS
ical follows the usual GNU command line syntax, with long options start-
ing with two dashes (`-'). A summary of all options is noted below:
-h, --help
Show summary of options
-g, --gregorian yyyymmdd
Specify the Gregorian date to be converted where 'y' stands for
year, 'm' for month and 'd' for day
-hi, --hijri yyyymmdd
Specify the Hijri date to be converted where 'y' stands for year,
'm' for month and 'd' for day
-u, --umm_alqura
Specify to use the Umm Al-Qura calculation method (used mostly in
Saudi Arabia)
-f, --fixed_view
Show a fixed week view (ie. start on Sun and end on Sat) else de-
fault to showing the preferred week view of the resulting calen-
dar (Gregorian starts on Sunday, Hijri starts on Saturday)
-d, --dual
Show both conversion from and to calendar months simultaneously
BACKGROUND
The Hijri calendar is used in most of the Arab world and is the symbolic
calendar of the Islamic faithed worldwide. This calendar is known as
the "Hijri" (based on the word "Hijrah" - denoting migration in Arabic)
to signal Prophet Mohammed's (PBUH) migration from Makkah to Medinah on
Thursday, July 15, 622 AD (Julian).
The Islamic Hijri calendar is strictly lunar (ie. moon-based) with
twelve lunar months which do not correspond or track their solar coun-
terparts (the Gregorian calendar is a solar or sun-based calendar). Lu-
nar years and thus Hijri years are, on average, about 354 days long re-
sulting in a Hijri year being roughly about 11 days shorter than its
Gregorian counterpart.
There is much discussion and confusion regarding how best to track the
Hijri calendar. A great deal of that confusion is based on the fact
that many relay on a human moon sighting to denote the start (or end) of
a month (each month of the Hijri calendar starts when a new moon's cres-
cent is observed or is made visible at sunset) as opposed to using an
empirical mathematic certainty. The methods presented in this applica-
tion and its underlying ITL library are strictly arithmetic in nature
and do NOT take moon-phases into consideration (in short, observational
approximation is not used).
LIMITATIONS
There is currently no Umm Al-Qura support.
REPORTING BUGS
Report bugs on the web using http://bugs.arabeyes.org
AUTHOR
Written by Nadim Shaikli as part of the Arabeyes.org project.
COPYRIGHT
ical is subject to the GNU General Public License (GPL).
Copyright © 2005, Arabeyes, Nadim Shaikli.
SEE ALSO
The ITL (Islamic Tools Library). It is the underlying requirement for
ical to function. The ITL library was created and is hosted at
www.arabeyes.org.
ical January 05, 2005 IDATE(1)
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