Hi! I'm a form!

This would get you a single text entry field, into which the user can
type whatever they want. There would also be a submit button, and a
reset button.

Because the method is post, weasel.cgi would get the form data on stdin,
in the form "foobar=whatevertheusertyped". If there were multiple
inputs, it would be "name1=value1&name=value2&name3=value3...". Spaces
get turned into +s, and any other
questionable characters will be escaped as %xx, where xx is the ASCII
hex for that character (man ascii is your friend), so you have to decode
all this. Then you can split the input on &, then split each chunk on =,
and you're set.

I write of things which I have neither seen nor learned from another,
things which are not and never could have been, and therefore my readers
should by no means believe them. --Lucian of Samosata