cal, ncal --- displays a calendar and the date of Easter
cal [-31jy] [-A number] [-B number] [-d yyyy-mm] [[month] year] cal [-31j] [-A number] [-B number] [-d yyyy-mm] -m month [year] ncal [-C] [-31jy] [-A number] [-B number] [-d yyyy-mm] [[month] year] ncal [-C] [-31j] [-A number] [-B number] [-d yyyy-mm] -m month [year] ncal [-31bhjJpwySM] [-A number] [-B number] [-H yyyy-mm-dd] [-d yyyy-mm] [-s country_code] [[month] year] ncal [-31bhJeoSM] [-A number] [-B number] [-d yyyy-mm] [year]
The cal utility displays a simple calendar in traditional format and ncal offers an alternative layout, more options and the date of Easter. The new format is a little cramped but it makes a year fit on a 25x80 terminal. If arguments are not specified, the current month is displayed. The options are as follows: -h Turns off highlighting of today. -J Display Julian Calendar, if combined with the -o option, display date of Orthodox Easter according to the Julian Calendar. -e Display date of Easter (for western churches). -j Display Julian days (days one-based, numbered from January 1). -m month Display the specified month. If month is specified as a decimal number, appending 'f' or 'p' displays the same month of the following or previous year respectively. -o Display date of Orthodox Easter (Greek and Russian Orthodox Churches). -p Print the country codes and switching days from Julian to Gregorian Calendar as they are assumed by ncal. The country code as determined from the local environment is marked with an asterisk. -s country_code Assume the switch from Julian to Gregorian Calendar at the date associated with the country_code. If not specified, ncal tries to guess the switch date from the local environment or falls back to September 2, 1752. This was when Great Britain and her colonies switched to the Gregorian Calendar. -w Print the number of the week below each week column. -y Display a calendar for the specified year. This option is implied when a year but no month are specified on the command line. -3 Display the previous, current and next month surrounding today. -1 Display only the current month. This is the default. -A number Months to add after. The specified number of months is added to the end of the display. This is in addition to any date range selected by the -y, -3, or -1 options. For example, "cal -y -B2 -A2" shows everything from November of the previous year to February of the following year. Negative numbers are allowed, in which case the specified number of months is subtracted. For example, "cal -y -B-6" shows July to December. And "cal -A11" simply shows the next 12 months. -B number Months to add before. The specified number of months is added to the beginning of the display. See -A for examples. -C Completely switch to cal mode. For cal like output only, use -b instead. -N Switch to ncal mode. -d yyyy-mm Use yyyy-mm as the current date (for debugging of date selection). -H yyyy-mm-dd Use yyyy-mm-dd as the current date (for debugging of highlighting). -M Weeks start on Monday. -S Weeks start on Sunday. -b Use oldstyle format for ncal output. A single parameter specifies the year (1--9999) to be displayed; note the year must be fully specified: "cal 89" will not display a calendar for 1989. Two parameters denote the month and year; the month is either a number between 1 and 12, or a full or abbreviated name as specified by the current locale. Month and year default to those of the current system clock and time zone (so "cal -m 8" will display a calendar for the month of August in the current year). Not all options can be used together. For example, the options -y, -3, and -1 are mutually exclusive. If inconsistent options are given, the later ones take precedence over the earlier ones. A year starts on January 1.
calendar(3), strftime(3)
A cal command appeared in Version 5 AT&T UNIX. The ncal command appeared in FreeBSD 2.2.6. The output of the cal command is supposed to be bit for bit compatible to the original Unix cal command, because its output is processed by other programs like CGI scripts, that should not be broken. Therefore it will always output 8 lines, even if only 7 contain data. This extra blank line also appears with the original cal command, at least on Solaris 8
The ncal command and manual were written by Wolfgang Helbig helbig@FreeBSD.org.
The assignment of Julian--Gregorian switching dates to country codes is historically naive for many countries. Not all options are compatible and using them in different orders will give varying results.
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.