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
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not be implemented on Linux.
NAMEcal — print a calendar
SYNOPSIScal [[month] year]
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.
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, repre‐
sented as a decimal integer from 1 to 9999.
The following environment variables shall affect the execution of cal:
LANG Provide a default value for the internationalization vari‐
ables that are unset or null. (See the Base Definitions vol‐
ume of POSIX.1‐2008, Section 8.2, Internationalization Vari‐
ables 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).
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
TZ Determine the timezone used to calculate the value of the
The standard output shall be used to display the calendar, in an
The standard error shall be used only for diagnostic messages.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
The following sections are informative.
refers to A.D. 83, not 1983.
Earlier versions of this standard incorrectly required that the com‐
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
A future version of this standard may support locale-specific recogni‐
tion of the date of adoption of the Gregorian calendar.
The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
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 Electri‐
cal 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.ker‐
IEEE/The Open Group 2013 CAL(1P)