NetBSD/usr.bin/cal/cal.1

.\"	$NetBSD: cal.1,v 1.19 2007/12/21 14:21:42 joerg Exp $
.\"
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.\" This code is derived from software contributed to Berkeley by
.\" Kim Letkeman.
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.\"     @(#)cal.1	8.2 (Berkeley) 4/28/95
.\"
.Dd December 21, 2007
.Dt CAL 1
.Os
.Sh NAME
.Nm cal
.Nd displays a calendar
.Sh SYNOPSIS
.Nm
.Op Fl hjry3
.Op Fl A Ar after
.Op Fl B Ar before
.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 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 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.
.It Fl 3
Same as
.Dq Fl A Ar 1 Fl B Ar 1 .
.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:
.Pp
.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 v6 .