Let us start with printing the current date and time, using the date command without any parameters.
Code:
$ date
Fri Jan  1 01:53:39 EST 2010

How to print yesterday’s date?


Unix date utility provides a quick way to achieve this, use date -d yesterday!
Code:
$ date -d yesterday
Thu Dec 31 01:51:39 EST 2009

How to print tomorrow’s date?


Use date -d tomorrow for echoing tomorrows date
Code:
$ date -d tomorrow
Sat Jan  2 01:51:57 EST 2010

How to print the date of the day after tomorrow


date "+2 days" (and so on for upcoming days)

Code:
$ date -d "+2 days"
Sun Jan  3 01:52:11 EST 2010

How to print the date of the day before yesterday?


date "-2 days" (and so on for previous days)
Code:
$ date -d "-2 days"
Wed Dec 30 01:52:16 EST 2009

How to print next Monday or a specific day


A more powerful way to get the date for a specific day next week or upcoming days,
Code:
$ date -d "next Wed"
Wed Jan  6 00:00:00 EST 2010

How to print the date of last Sunday


Code:
$ date -d "last Sun"
Sun Dec 27 00:00:00 EST 2009