gcal 4.1 Calculating and printing a wide variety of calendars

Это пакет GNU.

Gcal is a program to calculate and print calendars on the command-line. Calendars can be printed in 1-month, 3-month or whole-year views. In addition, eternal holiday lists can be generated for many countries, which can be complemented by user-made lists of fixed dates to make an agenda. Gcal can also calculate astronomical data, such as the phases of the moon, and supports alternative calendar formats: Julian, Gregorian, Islamic, Chinese and more.