writing cgi apps in sh

[dninja]

I have an environment where I only have sh (actually ash) available for writing cgi scripts in. I've tried googling around to find the best way to read and split down a POST into its constituent parts but can't find any examples. Can anyone give me any code or links to code to split a POST down in a sensible way?

I have a limited number of possible inputs, currently 5 values, if that makes any difference.