In addition to passing query strings, you can pass additional data, known as extra path information, as part of the URL. The server gauges where the CGI program name ends; anything following is deemed "extra" and is stored in the environment variable PATH_INFO. The following line calls a script with extra path information:
Everything after display.pl is the extra path. The PATH_TRANSLATED variable is also set, mapping the PATH_INFO to the document root (DOCUMENT_ROOT) directory (e.g., /usr/local/etc/httpd/public/cgi/cgi_doc.txt).