.\"-
.\" SPDX-License-Identifier: BSD-2-Clause
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.\" Copyright (c) 1997 Wolfgang Helbig
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.Dd March 7, 2019
.Dt CAL 1
.Os
.Sh NAME
.Nm cal ,
.Nm ncal
.Nd displays a calendar and the date of Easter
.Sh SYNOPSIS
.Nm
.Op Fl 3hjMy
.Op Fl A Ar number
.Op Fl B Ar number
.Oo
.Op Ar month
.Ar year
.Oc
.Nm
.Op Fl 3hjM
.Op Fl A Ar number
.Op Fl B Ar number
.Fl m Ar month
.Op Ar year
.Nm ncal
.Op Fl 3hjJpwy
.Op Fl A Ar number
.Op Fl B Ar number
.Op Fl s Ar country_code
.Oo
.Op Ar month
.Ar year
.Oc
.Nm ncal
.Op Fl 3hJeo
.Op Fl A Ar number
.Op Fl B Ar number
.Op Ar year
.Nm ncal
.Op Fl CN
.Op Fl H Ar yyyy-mm-dd
.Op Fl d Ar yyyy-mm
.Sh DESCRIPTION
The
.Nm
utility displays a simple calendar in traditional format and
.Nm ncal
offers an alternative layout, more options and the date of Easter.
The new format is a little cramped but it makes a year fit
on a 25x80 terminal.
If arguments are not specified,
the current month is displayed.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl h
Turns off highlighting of today.
.It Fl J
Display Julian Calendar, if combined with the
.Fl e
option, display date of Easter according to the Julian Calendar.
.It Fl e
Display date of Easter (for western churches).
.It Fl j
Display Julian days (days one-based, numbered from January 1).
.It Fl M
Display Monday as the first day of the week in
.Nm cal
mode.
.It Fl m Ar month
Display the specified
.Ar month .
If
.Ar month
is specified as a decimal number, it may be followed by the letter
.Ql f
or
.Ql p
to indicate the following or preceding month of that number,
respectively.
.It Fl o
Display date of Orthodox Easter (Greek and Russian
Orthodox Churches).
.It Fl p
Print the country codes and switching days from Julian to Gregorian
Calendar as they are assumed by
.Nm ncal .
The country code as determined from the local environment is marked
with an asterisk.
.It Fl s Ar country_code
Assume the switch from Julian to Gregorian Calendar at the date
associated with the
.Ar country_code .
If not specified,
.Nm ncal
tries to guess the switch date from the local environment or
falls back to September 2, 1752.
This was when Great
Britain and her colonies switched to the Gregorian Calendar.
.It Fl w
Print the number of the week below each week column.
.It Fl y
Display a calendar for the specified year.
.It Fl 3
Display the previous, current and next month surrounding today.
.It Fl A Ar number
Display the
.Ar number
of months after the current month.
.It Fl B Ar number
Display the
.Ar number
of months before the current month.
.It Fl C
Switch to
.Nm cal
mode.
.It Fl N
Switch to
.Nm ncal
mode.
.It Fl d Ar yyyy-mm
Use
.Ar yyyy-mm
as the current date (for debugging of date selection).
.It Fl H Ar yyyy-mm-dd
Use
.Ar yyyy-mm-dd
as the current date (for debugging of highlighting).
.El
.Pp
A single parameter specifies the year (1\(en9999) to be displayed;
note the year must be fully specified:
.Dq Li cal 89
will
.Em not
display a calendar for 1989.
Two parameters denote the month and
year; the month is either a number between 1 and 12, or a full or
abbreviated name as specified by the current locale.
Month and
year default to those of the current system clock and time zone (so
.Dq Li cal -m 8
will display a calendar for the month of August in the current
year).
.Pp
Not all options can be used together.
For example
.Dq Li -3 -A 2 -B 3 -y -m 7
would mean:
show me the three months around the seventh month, three before
that, two after that and the whole year.
.Nm ncal
will warn about these combinations.
.Pp
A year starts on January 1.
.Pp
Highlighting of dates is disabled if stdout is not a tty.
.Sh SEE ALSO
.Xr calendar 3 ,
.Xr strftime 3
.Sh STANDARDS
The
.Nm
utility is compliant with the
X/Open System Interfaces option of the
.St -p1003.1-2008
specification.
.Pp
The flags
.Op Fl 3ehJMopwy ,
as well as the ability to specify a month name as a single argument,
are extensions to that specification.
.Pp
The week number computed by
.Fl w
is compliant with the
.St -iso8601
specification.
.Sh HISTORY
A
.Nm
command appeared in
.At v1 .
The
.Nm ncal
command appeared in
.Fx 2.2.6 .
.Sh AUTHORS
The
.Nm ncal
command and manual were written by
.An Wolfgang Helbig Aq Mt helbig@FreeBSD.org .
.Sh BUGS
The assignment of Julian\(enGregorian switching dates to country
codes is historically naive for many countries.
.Pp
Not all options are compatible and using them in different orders
will give varying results.