A perpetual Jewish Calendar
by Danny Sadinoff portions by Michael J. Radwin
Hebcal is a program which prints out the days in the Jewish calendar for a given Gregorian year. Hebcal is fairly flexible in terms of which events in the Jewish calendar it displays. Each of the following can be individualy turned on or off:
- The Hebrew date
- Jewish Holidays (including Yom Ha'atzmaut and Yom HaShoah etc.)
- The weekly Sedrah
- The day of the week
- The days of the Omer
usage: hebcal [-8acdDeEFHhiorsStTwWyZ] [-b candle_lighting_minutes_before_sundown ] [-I file] [-Y yahrtzeit_file] [-C city] [-L longitude -l latitude] [-m havdalah_minutes_past_sundown ] [-z timezone] [[ month [ day ]] year ] hebcal help hebcal info hebcal cities hebcal warranty hebcal copying
Hebcal prints out Hebrew calendars one solar year at a time.
Given one argument, it will print out the calendar for that year.
Given two numeric arguments
mm yyyy, it prints out the calendar for
mm of year
will just print out the days of the omer for the current year.
Note: Use COMPLETE Years. You probably aren't interested in
hebcal 93, but rather hebcal 1993.
|-8||Use 8-bit Hebrew (ISO-8859-8-Logical).|
|-a||Use Ashkenazi Hebrew.|
|-b mins||Set candle-lighting to occur this many minutes before sundown|
|-c||Print candlelighting times.|
|-C city||Set latitude, longitude, and timezone according to specified city. This option implies the -c option.|
|-d||print the Hebrew date for the entire date range.|
|-D||print the Hebrew date for dates with some events|
|-e||Output "European" dates -- DD.MM.YYYY format.|
|-E||Output 24-hour times (e.g. 18:37 instead of 6:37).|
|-F||Output the Daf Yomi for the entire date range.|
|-h||Suppress default holidays.|
|-H||Use Hebrew date ranges - only needed when e.g.
|-i||Use Israeli sedra scheme.|
|-I file||Get non-yahrtzeit Hebrew user events from specified file. The format is:
|-l xx,yy||Set the latitude for solar calculations to
|-L xx,yy||Set the longitude for solar calculations to
|--lang LANG||Use ISO 639-1 LANG code (one of "he", "ru", or "pl")|
|-m mins||Set havdalah to occur this many minutes after sundown|
|-M||Print the molad on shabbat mevorchim.|
|-o||Add days of the omer.|
|-O||Output sunrise and sunset times every day.|
|-r||Tab delineated format.|
|-s||Add weekly sedrot on Saturday.|
|-S||Print sedrah of the week on all calendar days.|
|-t||Only output for today's date.|
|-T||Print today's pertinent information, no Gregorian date.|
|-w||Add day of the week.|
|-W||Weekly view. Omer, dafyomi, and non-date-specific zemanim are shown once a week, on the day which corresponds to the first day in the range.|
|-x||Suppress Rosh Chodesh.|
|-y||Print only last two digits of year.|
|--years N||Generate events for
|-Y file||Get yahrtzeit dates from specified file. The format is:
|-z timezone||Use specified timezone, overriding the
|-Z||EXPERIMENTAL Add zemanim (Alot HaShachar; Misheyakir; Kriat Shema, sof zeman; Tefilah, sof zeman; Chatzot hayom; Mincha Gedolah; Mincha Ketanah; Plag HaMincha; Tzait HaKochavim)|
|--help||Show help text|
|--version||Show version number|
Hebcal’s candlelighting times are only approximations. If you ever have any doubts about it’s times, consult your local halachic authority. If you enter geographic coordinates above the artic circle or antarctic circle, the times are guaranteed to be wrong.
Hebcal contains a small database of cities with their associated geographic information and time-zone information. The geographic and time information necessary to calculate sundown times can come to hebcal any of three ways:
- The default: the system manager sets a default city when the program is compiled.
- Hebcal looks in the environment variable
HEBCAL_CITYfor the name of a city in hebcal’s database, and if it finds one, hebcal will make that the new default city.
- 1 and 2 may be overridden by command line arguments, including those specified in the
HEBCAL_OPTSenvironment variable. The most natural way to do this is to use the
−c citycommand. This will localize hebcal to city. A list of the cities hebcal knows about can be obtained by typing
hebcal citiesat the command prompt. If the city you want isn’t on that list, you can directly control hebcal’s geographic information with the
−zswitches. Note that changing the geographic coordinates causes the timezone to default to 'UTC'. For a status report on customizations, type
hebcal infoat the command prompt.
Hebcal uses two environment variables:
- Hebcal uses this value as the default city for sunset calculations. A list of available cities is available with from hebcal with the command:
- The value of this variable is automatically processed as if it were typed at the command line before any other actual command-line arguments.
With contributions from
- Michael J. Radwin
- Aaron Peromsik (Daf Yomi, experimental zmanim feature)
- Ben Sandler (Molad and daily Sunrise/Sunset features)
calendar(1), emacs(1), hcal(1), hdate(1), omer(1), remind(1), rise(1)
The latest version of the code will be available from https://github.com/hebcal/hebcal
The original motivation for the algorithms in this program was the Tur Shulchan Aruch.
For version 3, much of the program was rewritten using Emacs 19’s calendar routines by Edward M. Reingold and Nachum Dershowitz. Their program is extremely clear and provides many instructive examples of fine calendar code in emacs-LISP.
For version 4, candle-lighting times were rewritting using Derick Rethans's timelib.
A well written treatment of the Jewish calendar for the layman can be found in Understanding the Jewish Calendar by Rabbi Nathan Bushwick. A more complete bibliography on the topic can be found there, as well as in the Encyclopedia Judaica entry on the calendar.
- hebcal help
- Prints a shorter version of this manpage, with comments on each option.
- hebcal info
- Prints the version number and default values of the program.
- hebcal cities
- Prints a list of cities which hebcal knows about, suitable as arguments to the −C city option.
- hebcal copying
- Prints the GNU license, with information about copying the program. See below.
- hebcal warranty
- Tells you how there’s NO WARRANTY for hebcal.
This is just a program I wrote during summer school and while avoiding my senior project. It should not be invested with any sort of halachic authority.
Hebrew dates are only valid before sundown on that secular date. An option to control this will be added in a later release.
Negative longitudes are EAST of Greenwich.
Some combinations of options produce weird results, e.g.
hebcal -dH nisan 5744
hebcal -dH 5744
This comes into play when you use the HEBCAL_OPTS environment variable.
The sunup/sundown routines aren’t accurate enough. If you enter geographic coordinates above the artic circle or antarctic circle, the times are guaranteed to be wrong.
Hebcal only translates between the Gregorian calendar and the Jewish calendar. This means that the results will be at least partly useless where and when the Gregorian calendar was not used, e.g. before the 1752 in Britain and before circa 1918 in Russia. See "Daylight saving time" on Wikipedia for a splendid chart depicting when the changeover from the Julian to the Gregorian calendars occurred in various places.
Hebcal cannot handle date computations before 2 C.E. sorry.
Build & Install
To build hebcal from the source repository, you'll need a few more tools than are needed in order to build from distributions. In particular, you'll need
- GNU autoconf version 2.59
- GNU automake version 1.9.5 or later
- GNU m4 version 1.4.3 or later
- GNU make v3.79 or later
- Perl v5.0 or later
Once you have those, you can prepare the build environment as follows:
aclocal && autoconf && automake --foreign --add-missing && ./configure && make
If you would like customize the program for your city, pass additional options to
cities.h. If your city is in there, run
configure using the
--with-default-city=CITYNAME option as follows:
you may have to quote spaces:
./configure --with-default-city="Los Angeles"
If your city is NOT on the list, then in order to customize hebcal to your city, you will need to pass it the latitude, longitude, and timezone (see the manual).
Suppose you live in Oshkosh, Wisconsin.
Your lattitude is 44d1'29", and your longitude is 88d32'33".
You are in timezone
We'll round the geographic coordinates to the nearest minute.
In order to get candlelighting times for the current year, you would type
hebcal -ch -l44,1 -L 88,33 -z America/Chicago
Now this can get rough on the fingers if you do it a lot, so the
HEBCAL_OPTS environment variable is available for you to use. Every time hebcal is run, it checks this variable. If it is non-empty, the arguments in that variable are read as though they were typed at the command line before the ones you actually type.
So you might set
HEBCAL_OPTS to be
-l44,1 -L 88,33 -z America/Chicago
and if you type
hebcal will think you typed
hebcal -l44,1 -L 88,33 -z America/Chicago -ch
REMEMBER: negative longitudes are EAST of Greenwich.
For information on setting environment variables, consult your local guru.
Once an install is complete, there are three ways to change cities, or pick a city not on the list:
- change the
- change the
HEBCAL_OPTSvariable to reflect the new city's coordinates.
- pass a
-C cityargument to hebcal.
You can check where hebcal thinks it is by typing
at the command line.
Copyright (C) 1994-2011 Danny Sadinoff Portions Copyright (c) 2011 Michael J. Radwin. All Rights Reserved.
Hebcal is distributed under the GNU Public License. The program and its source code may be freely distributed. For details, see the file COPYING in the distribution.
If you are going to use this program, please drop me a line. I'd like to know who you are, what version you're using, and how you're using hebcal, and anything else you'd like to tell me, so that I can adjust the program to meet users' needs.
I am NOT demanding payment for the use of my program, but writing this program DID take time. The "free" in the GNU public license refers to distribution, not necessarily payment. Feel free to send $10 or multiples of $18 or just a postcard to me at my US Mail address (email me for it).
send email to: firstname.lastname@example.org