How to calculate a date a week ago from today

Question

I wanna calculate the date a week ago from today with a specific format and put it in to a variable. For example, today is Nov 21st. 2014, and I wanna print out

Answer 1

Why not just subtract X days from the "mday" field of localtime? This example shows subtracting 60 days from the end of august. I'm not sure who corrects the month but I think I'm getting the right answer...

$ date
Wed Aug 30 14:34:14 DFT 2017
$ perl -MPOSIX -e '@t=localtime time; $t[3] -= 60; print strftime( "%Y/%m/%d", @t), "\n";'
2017/07/01