How to get the date of Easter using shell command

It is very easy task as it requires only the use of ncal command.

Get the date of Easter for the current year:

$ ncal -e
March 31 2013

Get the date of Easter for the next year:

$ ncal -e $(date --date "next year" +"%Y")
April 20 2014

Get the date of Easter for the 2015 year:

$ ncal -e 2015
April  5 2015