Beginner looking for survey script

I'm looking for a simple bit of code to interrupt all visitors to a site so they can submit a brief survey and then automatically continue to their desired destination. The server is Apache 2.0 on Solaris. I have already set a global header to redirect all visitors to the survey page if they do not have a cookie. The survey page needs to write their form data to a plain text file (NOT MySQL), set a cookie to prevent them from seeing the survey again, and finally show a "Thank you" page with a link to their original destination. Has anyone run across such a thing, or know how to create it easily? Thank you kindly. -josh