subtract days from a date in bash

Question

I want to subtract \"number of days\" from a date in bash. I am trying something like this ..

echo $dataset_date #output is 2013-08-07

echo $date_diff #outp         


        

Answer 1

Here is my solution:

echo $[$[$(date +%s)-$(date -d "2015-03-03 00:00:00" +%s)]/60/60/24]

It calculates number of days between now and 2015-03-03 00:00:00