NAME¶
idate - A Gregorian/Meladi to/from Hijri/Islamic date converter
SYNOPSIS¶
idate [
--gregorian yyyymmdd
] [
--hijri
yyyymmdd
] [
--simple] [
--umm_alqura] [
--help]
DESCRIPTION¶
The
idate program is a Gregorian to Hijri (and vice-versa) date
converter. The application 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.
idate 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.
idate 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.
idate when run without any command-line options uses the host machine's
current Gregorian date and converts it to Hijri.
OPTIONS¶
idate follows the usual GNU command line syntax, with long options
starting 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
- -s, --simple
- Specify a simplified output mode
- -u, --umm_alqura
- Specify to use the Umm Al-Qura calculation method (used
mostly in Saudi Arabia)
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) or July 19, 622 AD (Gregorian).
The Islamic Hijri calendar is strictly lunar (ie. moon-based) with twelve lunar
months which do not correspond or track their solar counterparts (the
Gregorian calendar is a solar or sun-based calendar). Lunar years and thus
Hijri years are, on average, about 354 days long resulting 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 rely
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 crescent is observed or is made
visible at sunset) as opposed to using an empirical mathematic certainty. The
methods presented in this application 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¶
The Umm Al-Qura option doesn't function with pre-epoch settings.
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¶
idate is subject to the GNU General Public License (GPL).
Copyright © 2005, Arabeyes, Nadim Shaikli.
SEE ALSO¶
The ITL library (libitl) from the Islamic Tools and Libraries project. It is the
underlying requirement for
idate to function. The ITL library was
created and is hosted at
www.arabeyes.org.