cal - Display the Calendar.
Display the current month:
cal
Display current month without highlighting today's date:
cal -h
Display calendar for a specific month (april):
cal -m 4
Display calendar for a specific year (2001):
cal -y 2001
Display the previous, current, and the next month:
cal -3
Display the current and next two months:
cal -A 2
Display the previous two months and the current month:
cal -B 2
Display five months with the current month in the middle:
cal -B2 -A2
Display a specific month and year:
cal -d 2001-01
Display Julian days (days one-based which numbered from January 1):
cal -j