Let's have a more concrete example of ambiguity. "${*##*[ ]}" is a valid POSIX approach to getting the last parameter but it doesn't work in ksh or bash. Thos

Let's have a more concrete example of ambiguity. "${*##*[ ]}" is a valid POSIX approach to getting the last parameter but it doesn't work in ksh or bash. Those shells apply the pattern to each parameter in turn when used on '*' or '@'. That text is from a developer who has profound depth. A portable method to extract the last argument is: for last do : done This ambiguity and subtlety is not good.