我希望以下解决方案可以为您提供帮助:

I hope this below solution can help you:

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

这将始终打印给定日期(或日期本身)之前的星期日.

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

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

这将始终打印给定日期之前的星期日(而不是日期本身).

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