<P> When a web server executes a CGI script it provides input to the console / shell program using environment variables or "standard input". Standard input is like typing data into a console / shell program; in the case of a CGI script, the web server does the typing . The CGI script writes data out to "standard output" and that output is sent to the client (the web browser) as a HTML page . </P> <P> The following Perl program shows all the environment variables passed by the Web server: </P> <P> If a Web browser issues a request for the environment variables at http://example.com/cgi-bin/printenv.pl/foo/bar?var1=value1&var2=with%20percent%20encoding, a 64 - bit Microsoft Windows web server running cygwin returns the following information: </P> <P> Some, but not all, of these variables are defined by the CGI standard . Some, such as PATH_INFO, QUERY_STRING, and the ones starting with HTTP_, pass information along from the HTTP request . </P>

Common gateway interface(cgi) is which of the following