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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.1‐2008, 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.1‐2008, Chapter 8, Environment Variables
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced
during the conversion of the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 CAL(1POSIX)