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.