freebsd-dev/usr.bin/calendar/calendar.1

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.\"     @(#)calendar.1  8.1 (Berkeley) 6/29/93
.\" $FreeBSD$
.\"
.Dd November 5, 2020
.Dt CALENDAR 1
.Os
.Sh NAME
.Nm calendar
.Nd reminder service
.Sh SYNOPSIS
.Nm
.Op Fl A Ar num
.Op Fl a
.Op Fl B Ar num
.Op Fl D Ar moon|sun
.Op Fl d
.Op Fl F Ar friday
.Op Fl f Ar calendarfile
.Op Fl l Ar longitude
.Oo
.Bk -words
.Fl t Ar dd Ns
.Sm off
.Op . Ar mm Op . Ar year
.Sm on
.Ek
.Oc
.Op Fl U Ar UTC-offset
.Op Fl W Ar num
.Sh DESCRIPTION
The
.Nm
utility checks the current directory for a file named
.Pa calendar
and displays lines that fall into the specified date range.
On the day before a weekend (normally Friday), events for the next
three days are displayed.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl A Ar num
Print lines from today and the next
.Ar num
days (forward, future).
.It Fl a
Process the ``calendar'' files for users found in
.Pa /etc/passwd
and mail the results
to them.
This can result in multiple messages for specific files, since
.Pa /etc/passwd
does not require home directories to be unique.
In particular, by default
.Ar root ,
.Ar toor
and
.Ar daemon
share the same home directory.
If this directory contains calendar information,
.Nm
will process the file three times.
.Pp
This option requires super-user privileges.
.It Fl B Ar num
Print lines from today and the previous
.Ar num
days (backward, past).
.It Fl D Ar moon|sun
Print UTC offset, longitude and moon or sun information.
.It Fl d
Debug option: print current date information.
.It Fl F Ar friday
Specify which day of the week is ``Friday'' (the day before the
weekend begins).
Default is 5.
.It Fl f Pa calendarfile
Use
.Pa calendarfile
as the default calendar file.
.It Fl l Ar longitude
Perform lunar and solar calculations from this longitude.
If neither longitude nor UTC offset is specified, the calculations will
be based on the difference between UTC time and localtime.
If both are specified, UTC offset overrides longitude.
.It Xo Fl t
.Sm off
.Ar dd
.Op . Ar mm Op . Ar year
.Sm on
.Xc
For test purposes only: set date directly to argument values.
.It Fl U Ar UTC-offset
Perform lunar and solar calculations from this UTC offset.
If neither UTC offset nor longitude is specified, the calculations
will be based on the difference between UTC time and localtime.
If both are specified, UTC offset overrides longitude.
.It Fl W Ar num
Print lines from today and the next
.Ar num
days (forward, future).
Ignore weekends when calculating the number of days.
.El
.Sh FILE FORMAT
To handle calendars in your national code table you can specify
.Dq LANG=<locale_name>
in the calendar file as early as possible.
.Pp
To handle the local name of sequences, you can specify them as:
.Dq SEQUENCE=<first> <second> <third> <fourth> <fifth> <last>
in the calendar file as early as possible.
.Pp
The names of the following special days are recognized:
.Bl -tag -width 123456789012345 -compact
.It Easter
Catholic Easter.
.It Paskha
Orthodox Easter.
.It NewMoon
The lunar New Moon.
.It FullMoon
The lunar Full Moon.
.It MarEquinox
The solar equinox in March.
.It JunSolstice
The solar solstice in June.
.It SepEquinox
The solar equinox in September.
.It DecSolstice
The solar solstice in December.
.It ChineseNewYear
The first day of the Chinese year.
.El
These names may be reassigned to their local names via an assignment
like
.Dq Easter=Pasen
in the calendar file.
.Pp
Other lines should begin with a month and day.
They may be entered in almost any format, either numeric or as character
strings.
If the proper locale is set, national month and weekday
names can be used.
A single asterisk (``*'') matches every month.
A day without a month matches that day of every week.
A month without a day matches the first of that month.
Two numbers default to the month followed by the day.
Lines with leading tabs default to the last entered date, allowing
multiple line specifications for a single date.
.Pp
The names of the recognized special days may be followed by a
positive or negative integer, like:
.Dq Easter+3
or
.Dq Paskha-4 .
.Pp
Weekdays may be followed by ``-4'' ...\& ``+5'' (aliases for
last, first, second, third, fourth) for moving events like
``the last Monday in April''.
.Pp
By convention, dates followed by an asterisk are not fixed, i.e., change
from year to year.
.Pp
Day descriptions start after the first <tab> character in the line;
if the line does not contain a <tab> character, it is not displayed.
If the first character in the line is a <tab> character, it is treated as
a continuation of the previous line.
.Pp
The
.Nm
file is preprocessed by a limited subset of
.Xr cpp 1
internally, allowing the inclusion of shared files such as
lists of company holidays or meetings.
This limited subset consists of \fB#include\fR, \fB#define\fR,
\fB#undef\fR, \fB#ifdef\fR, \fB#ifndef\fR, \fB#else\fR, \fB#warning\fR,
and \fB#error\fR.
.Pp
Conditions can be nested and the consistency of opening and closing
instructions is checked.
Only the first word after #define is used as the name of the
condition variable being defined.
More than word following #ifdef, #ifndef, or #undef is considered a syntax
error, since names cannot include white-space.
Included files are parsed in a global scope with regard to the condition
variables being defined or tested therein.
All conditional blocks are implicitly closed at the end of a file,
and missing #endif instructions are assumed to be present on implied
succeeding lines.
.Pp
If the shared file is not referenced by a full pathname,
.Nm
searches in the current (or home) directory first, and then in the
directory
.Pa /usr/share/calendar .
Empty lines and text protected by the C commenting syntax
.Pq Li /* ... */
or
.Pq Li //
are ignored.
.Pp
Some possible calendar entries (<tab> characters highlighted by
\fB\et\fR sequence):
.Bd -unfilled -offset indent
LANG=C
Easter=Ostern

#include <calendar.usholiday>
#include <calendar.birthday>

6/15\fB\et\fRJune 15 (if ambiguous, will default to month/day).
Jun. 15\fB\et\fRJune 15.
15 June\fB\et\fRJune 15.
Thursday\fB\et\fREvery Thursday.
June\fB\et\fREvery June 1st.
15 *\fB\et\fR15th of every month.
2010/4/15\fB\et\fR15 April 2010

May Sun+2\fB\et\fRsecond Sunday in May (Muttertag)
04/SunLast\fB\et\fRlast Sunday in April,
\fB\et\fRsummer time in Europe
Easter\fB\et\fREaster
Ostern-2\fB\et\fRGood Friday (2 days before Easter)
Paskha\fB\et\fROrthodox Easter

.Ed
.Sh FILES
.Bl -tag -width calendar.christian -compact
.It Pa calendar
file in current directory.
.It Pa ~/.calendar
.Pa calendar
HOME directory.
A chdir is done into this directory if it exists.
.It Pa ~/.calendar/calendar
calendar file to use if no calendar file exists in the current directory.
.It Pa ~/.calendar/nomail
do not send mail if this file exists.
.It Pa /usr/share/calendar
system wide location of calendar files provided as part of the base system.
.It Pa /usr/local/share/calendar
system wide location for calendar files provided by a port or package.
.El
.Pp
The order of precedence in searches for a calendar file is:
current directory, ~/.calendar, /usr/local/share/calendar, /usr/share/calendar.
Files of similar names are ignored in lower precedence locations.
.Pp
The following default calendar files are provided by the
deskutils/calendar-data port.
.Pp
.Bl -tag -width calendar.southafrica -compact
.It Pa calendar.all
File which includes all the default files.
.It Pa calendar.australia
Calendar of events in Australia.
.It Pa calendar.birthday
Births and deaths of famous (and not-so-famous) people.
.It Pa calendar.christian
Christian holidays.
This calendar should be updated yearly by the local system administrator
so that roving holidays are set correctly for the current year.
.It Pa calendar.computer
Days of special significance to computer people.
.It Pa calendar.croatian
Calendar of events in Croatia.
.It Pa calendar.dutch
Calendar of events in the Netherlands.
.It Pa calendar.freebsd
Birthdays of
.Fx
committers.
.It Pa calendar.french
Calendar of events in France.
.It Pa calendar.german
Calendar of events in Germany.
.It Pa calendar.history
Everything else, mostly U.S.\& historical events.
.It Pa calendar.holiday
Other holidays, including the not-well-known, obscure, and
.Em really
obscure.
.It Pa calendar.judaic
Jewish holidays.
The entries for this calendar have been obtained from the
deskutils/hebcal port.
.It Pa calendar.music
Musical events, births, and deaths.
Strongly oriented toward rock 'n' roll.
.It Pa calendar.newzealand
Calendar of events in New Zealand.
.It Pa calendar.russian
Russian calendar.
.It Pa calendar.southafrica
Calendar of events in South Africa.
.It Pa calendar.usholiday
U.S.\& holidays.
This calendar should be updated yearly by the local system administrator
so that roving holidays are set correctly for the current year.
.It Pa calendar.world
Includes all calendar files except for national files.
.El
.Sh COMPATIBILITY
The
.Nm
program previously selected lines which had the correct date anywhere
in the line.
This is no longer true, the date is only recognized when it occurs
at the beginning of a line.
.Sh SEE ALSO
.Xr at 1 ,
.Xr mail 1 ,
.Xr cron 8
.Sh HISTORY
A
.Nm
command appeared in
.At v7 .
.Sh NOTES
Chinese New Year is calculated at 120 degrees east of Greenwich,
which roughly corresponds with the east coast of China.
For people west of China, this might result that the start of Chinese
New Year and the day of the related new moon might differ.
.Pp
The phases of the moon and the longitude of the sun are calculated
against the local position which corresponds with 30 degrees times
the time-difference towards Greenwich.
.Pp
The new and full moons are happening on the day indicated: They
might happen in the time period in the early night or in the late
evening.
It does not indicate that they are starting in the night on that date.
.Pp
Because of minor differences between the output of the formulas
used and other sources on the Internet, Druids and Werewolves should
double-check the start and end time of solar and lunar events.
.Sh BUGS
The
.Nm
does only recognise the cpp directives #include, #define, #ifdef,
#ifndef and #else.
It supports nested conditions, but does not perform any validation
on the correct use and nesting of conditions.
#endif without prior #ifdef or #define is ignored and #else outside
a conditional section skips input lines up to the next #endif.
.Pp
There is no possibility to properly specify the local position
needed for solar and lunar calculations.