.\" $NetBSD: cal.1,v 1.23 2018/05/29 08:37:33 wiz Exp $
.\"
.\" Copyright (c) 1989, 1990, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Kim Letkeman.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)cal.1 8.2 (Berkeley) 4/28/95
.\"
.Dd May 29, 2018
.Dt CAL 1
.Os
.Sh NAME
.Nm cal
.Nd displays a calendar
.Sh SYNOPSIS
.Nm
.Op Fl 3hjry
.Op Fl A Ar after
.Op Fl B Ar before
.Op Fl C Ar context
.Op Fl d Ar day-of-week
.Op Fl R Ar reform-spec
.Op Oo Ar month Oc Ar year
.Sh DESCRIPTION
.Nm
displays a simple calendar.
If arguments are not specified,
the current month is displayed.
The options are as follows:
.Bl -tag -width Ds
.It Fl 3
Same as
.Dq Fl A Ar 1 Fl B Ar 1 .
.It Fl A Ar after
Display
.Ar after
months after the specified month.
.It Fl B Ar before
Display
.Ar before
months before the specified month.
.It Fl C Ar context
Display
.Ar context
months before and after the specified month.
.It Fl d Ar day-of-week
Specifies the day of the week on which the calendar should start.
Valid values are 0 through 6, presenting Sunday through Saturday,
inclusively.
The default output starts on Sundays.
.It Fl h
Highlight the current day, if present in the displayed calendar.
If output is to a terminal, then the appropriate terminal sequences
are used, otherwise overstriking is used.
If more than one
.Fl h
is used and output is to a terminal, the current date will be
highlighted in inverse video instead of bold.
.It Fl j
Display Julian dates (days one-based, numbered from January 1).
.It Fl R Ar reform-spec
Selects an alternate Gregorian reform point from the default of
September 3rd, 1752.
The
.Ar reform-spec
can be selected by one of the built-in names (see
.Sx NOTES
for a list) or by a date of the form YYYY/MM/DD.
The date and month may be omitted, provided that what is specified
uniquely selects a given built-in reform point.
If an exact date is specified, then that date is taken to be the first
missing date of the Gregorian Reform to be applied.
.It Fl r
Display the month in which the Gregorian Reform adjustment was
applied, if no other
.Ar month
or
.Ar year
information is given.
If used in conjunction with
.Fl y ,
then the entire year is displayed.
.It Fl y
Display a calendar for the current year.
.El
.Pp
If no parameters are specified, the current month's calendar is
displayed.
A single parameter specifies the year and optionally the month
in ISO format:
.Dq Li cal 2007-12
Two parameters denote the month (1 - 12) and year.
Note that the century must be included in the year.
.Pp
A year starts on Jan 1.
.Sh NOTES
In the USA and Great Britain the Gregorian Reformation occurred in 1752.
By this time, most countries had recognized the reformation (although a
few did not recognize it until the 1900's.)
Eleven days following September 2, 1752 were eliminated by the reformation,
so the calendar for that month is a bit unusual.
.Pp
In view of the chaotic way the Gregorian calendar was adopted throughout
the world in the years between 1582 and 1928 make sure to take into account
the date of the Gregorian Reformation in your region if you are checking a
calendar for a very old date.
.Pp
.Nm
has a decent built-in list of Gregorian Reform dates and the names of
the countries where the reform was adopted:
.Bd -literal
Italy Oct. 5, 1582 Denmark Feb. 19, 1700
Spain Oct. 5, 1582 Great Britain Sep. 3, 1752
Portugal Oct. 5, 1582 Sweden Feb. 18, 1753
Poland Oct. 5, 1582 Finland Feb. 18, 1753
France Dec. 12, 1582 Japan Dec. 20, 1872
Luxembourg Dec. 22, 1582 China Nov. 7, 1911
Netherlands Dec. 22, 1582 Bulgaria Apr. 1, 1916
Bavaria Oct. 6, 1583 U.S.S.R. Feb. 1, 1918
Austria Jan. 7, 1584 Serbia Jan. 19, 1919
Switzerland Jan. 12, 1584 Romania Jan. 19, 1919
Hungary Oct. 22, 1587 Greece Mar. 10, 1924
Germany Feb. 19, 1700 Turkey Dec. 19, 1925
Norway Feb. 19, 1700 Egypt Sep. 18, 1928
.Ed
.Pp
The country known as
.Em Great Britain
can also be referred to as
.Em England
since that has less letters and no spaces in it.
This is meant only as a measure of expediency, not as a possible
slight to anyone involved.
.Sh HISTORY
A
.Nm
command appeared in
.At v1 .
