As you start to program more advanced CGI applications, you'll want to store data so you can use it later. Maybe you have a guestbook program and want to keep a log of the names and email addresses of visitors, or a page counter that must update a counter file, or a program that scans a flat-file database and draws info from it to generate a page. You can do this by reading and writing data files (often called file I/O). For more Information please have a look @ http://www.cgi101.com/book/ch6/text.html