cal man page

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.

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.

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.

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.

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.

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

Info

2013 IEEE/The Open Group POSIX Programmer's Manual