How do i get last sunday date from a given date in unix

Question

get last sunday date as output from a given date (not current date) as input

Example input: 08-30-2017 (%m-%d-%Y)

output should be last sunday: 08-27-2017

Answer 1

I hope this below solution can help you:

export day=08-30-2017
date -d "$day -$(date -d $day +%w) days"

This will always print the Sunday before the given date (or the date itself).

date -d "$day -$(date -d $day +%u) days"

This will always print the Sunday before the given date (and never the date itself).