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.
The following environment variables shall affect the execution of cal:
Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, 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 LC_MESSAGES.
Determine the timezone used to calculate the value of the
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 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