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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.