cal(1) on Linux
The text d75f134e51e0, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye) shipped it.
displays a calendar and the date of Easter
Flags it lists
-
-1 -
-3 -
-A -
-B -
-C -
-H -
-J -
-M -
-S -
-W -
-b -
-d -
-e -
-h -
-j -
-m -
-o -
-p -
-s -
-w -
-y