Section: POSIX Programmer's Manual (1P)
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
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or the interface may not be implemented on Linux.
--- print a calendar
cal [[month] year]
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
If no operands are given,
shall produce a one-month calendar for the current month in the
current year. If only the
operand is given,
shall produce a calendar for all twelve months in the given calendar
year. If both
operands are given,
shall produce a one-month calendar for the given month in the given year.
The following operands shall be supported:
Specify the month to be displayed, represented as a decimal integer
from 1 (January) to 12 (December).
Specify the year for which the calendar is displayed, represented as a
decimal integer from 1 to 9999.
The following environment variables shall affect the execution of
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.)
If set to a non-empty string value, override the values of all the
other internationalization variables.
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.
Determine the format and contents of the calendar.
Determine the location of message catalogs for the processing of
Determine the timezone used to calculate the value of the current
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:
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 command:
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
utility. The description has been updated to match historic practice.
When only the
operand is given,
writes a twelve-month calendar for the specified year.
A future version of this standard may support locale-specific
recognition of the date of adoption of the Gregorian calendar.
The Base Definitions volume of POSIX.1-2008,
, Environment Variables
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
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