Specify a previous date as start date in shell script

Hi,

I am trying to modify a script which accepts date in format dd/mm/yy. I am trying to modify the script so that it retrieves the date that was 15 days earlier from today as start date. Eg.if today is 05/09/2006, the script should retrieve 21/08/2006 as start date. Is there any script/code to get this date in dd/mm/yy format 15 days earlier?

See this post.

That excellent..thank you very much