无法在Bash中使用ddmmyyyy格式递增日期

Question

Why does this:

date +%d%m%Y -d "01052018 + 1 day"

error w/

date: invalid date `02062018 + 1 day'

on CentOS 7.3 in CEST? I've tried a few variations

date +%d%m%Y -d "$date 12:00 + 1 day"
date +%d%m%Y -ud "$date UTC + 1 day"

to no avail. What am I missing?

Answer 1

GNU date does not support date format ddmmyyyy of type as you can see from Pure numbers in date strings , you need to change it of type yyyymmdd to make it work

date -d "20180501 + 1 day"

or with UTC as

date -ud "20180501 UTC + 1 day"

If your original string is from a variable and you need a work-around to make it compatible with the format above, do it using parameter expansion

rawdate="02062018"
compatDate="${rawdate:4}${rawdate:2:2}${rawdate:0:2}"

and use the variable compatDate in the date command

date -d "${compatDate} + 1 day"