All the Perl CGI program will have access to the following environment variables. These variables play an important role while writing any CGI program in Perl.
Sr.No | Variables Names & Description |
---|---|
1 | CONTENT_TYPE The data type of the content. Used when the client is sending attached content to the server. For example file upload, etc. |
2 | CONTENT_LENGTH The length of the query information. It's available only for POST requests |
3 | HTTP_COOKIE Returns the set cookies in the form of key & value pair. |
4 | HTTP_USER_AGENT The User-Agent request-header field contains information about the user agent originating the request. Its name of the web browser. |
5 | PATH_INFO The path for the CGI script. |
6 | QUERY_STRING The URL-encoded information that is sent with GET method request. |
7 | REMOTE_ADDR The IP address of the remote host making the request. This can be useful for logging or for authentication purpose. |
8 | REMOTE_HOST The fully qualified name of the host making the request. If this information is not available then REMOTE_ADDR can be used to get IR address. |
9 | REQUEST_METHOD The method used to make the request. The most common methods are GET and POST. |
10 | SCRIPT_FILENAME The full path to the CGI script. |
11 | SCRIPT_NAME The name of the CGI script. |
12 | SERVER_NAME The server's hostname or IP Address. |
13 | SERVER_SOFTWARE The name and version of the software the server is running. |
Here is a small Perl CGI program to list down all the CGI variables supported by your Web server. Click this link to see the result Get Environment
#!/usr/bin/perl print "Content-type: text/html\n\n"; print "<font size=+1>Environment</font>\n"; foreach (sort keys %ENV) { print "<b>$_</b>: $ENV{$_}<br>\n"; } 1;