Gcal is a program for calculating and printing calendars.  Gcal
displays hybrid and proleptic Julian and Gregorian calendar sheets,
respectively, for one month, three months or a whole year.  It also
displays eternal holiday lists for many countries around the globe,
and features a very powerful creation of fixed date lists that can
be used for reminding purposes.  Gcal can calculate various
astronomical data and times of the Sun and the Moon for any location,
precisely enough for most civil purposes.  Gcal supports some other
calendar systems, for example the Chinese and Japanese calendar,
the Hebrew calendar and the civil Islamic calendar.

Note that this port will install these utilities with a `g' prefix,
eg., gdate, gexpr, gtest, but the texinfo documentation will refer to
these utilities without the `g' prefix.

WWW: http://www.gnu.org/software/gcal/gcal.html