cal(1p) — Linux manual page
CAL(1P) POSIX Programmer's Manual CAL(1P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
cal — print a calendar
SYNOPSIS
cal [[month] year]
DESCRIPTION
The cal utility shall write a calendar to standard output using
the Julian calendar for dates from January 1, 1 through September
2, 1752 and the Gregorian calendar for dates from September 14,
1752 through December 31, 9999 as though the Gregorian calendar
had been adopted on September 14, 1752.
If no operands are given, cal shall produce a one-month calendar
for the current month in the current year. If only the year
operand is given, cal shall produce a calendar for all twelve
months in the given calendar year. If both month and year
operands are given, cal shall produce a one-month calendar for
the given month in the given year.
OPTIONS
None.
OPERANDS
The following operands shall be supported:
month Specify the month to be displayed, represented as a
decimal integer from 1 (January) to 12 (December).
year Specify the year for which the calendar is displayed,
represented as a decimal integer from 1 to 9999.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
cal:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence of
internationalization variables used to determine the
values of locale categories.)
LC_ALL If set to a non-empty string value, override the values
of all the other internationalization variables.
LC_CTYPE Determine the locale for the interpretation of
sequences of bytes of text data as characters (for
example, single-byte as opposed to multi-byte
characters in arguments).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error, and informative messages written to
standard output.
LC_TIME Determine the format and contents of the calendar.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
TZ Determine the timezone used to calculate the value of
the current month.
ASYNCHRONOUS EVENTS
Default.
STDOUT
The standard output shall be used to display the calendar, in an
unspecified format.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
Note that:
cal 83
refers to A.D. 83, not 1983.
EXAMPLES
None.
RATIONALE
Earlier versions of this standard incorrectly required that the
command:
cal 2000
write a one-month calendar for the current calendar month (no
matter what the current year is) in the year 2000 to standard
output. This did not match historic practice in any known version
of the cal utility. The description has been updated to match
historic practice. When only the year operand is given, cal
writes a twelve-month calendar for the specified year.
FUTURE DIRECTIONS
A future version of this standard may support locale-specific
recognition of the date of adoption of the Gregorian calendar.
SEE ALSO
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any
discrepancy between this version and the original IEEE and The
Open Group Standard, the original IEEE and The Open Group
Standard is the referee document. The original Standard can be
obtained online at http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page
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