Write a message to standard error when attempting to expand a variable that is not set, and if the shell is not interactive, exit immediately.
Dee ozi na njehie zuru oke mgbe ị na-anwa ịgbasa agbanwe nke na-adịghị edozi, ma ọ bụrụ na sheba enweghị mmekọrịta, pụọ ozugbo.