Not able to manipulate date on Unix shell script (date: illegal option — d)

问题

I have a requirement to add 10 days to current date and assign it to a variable. But I am getting error:

date: illegal option -- d

This is what I tried:

$> NEW_expration_DATE=$(date -d "+10 days")

Result:

date: illegal option -- d
Usage: date [-u] [+Field Descriptors]

回答1:

Try this: NEW_expration_DATE=$(gdate -d "+10 days")

回答2:

It looks like you are using a POSIX shell, and that there is no way to do simple date arithmetic in here.

I found a guy who explains it and who coded something to substract dates. You may be able to adapt it for your case: https://unix.stackexchange.com/a/7220/162444

Good luck!

来源：https://stackoverflow.com/questions/36631711/not-able-to-manipulate-date-on-unix-shell-script-date-illegal-option-d