-1

Display single month output. (This is the default.)

-3

Display prev/current/next month output.

-s

Display Sunday as the first day of the week. (This is the default.)

-m

Display Monday as the first day of the week.

-j

Display Julian dates (days one-based, numbered from January 1).

-y

Display a calendar for the current year.

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 (1 - 12) and year. If no parameters are specified, the current month's calendar is displayed.

A year starts on Jan 1.

The Gregorian Reformation is assumed to have occurred in 1752 on the 3rd of September. By this time, most countries had recognized the reformation (although a few did not recognize it until the early 1900's.) Ten days following that date were eliminated by the reformation, so the calendar for that month is a bit unusual.