cgi environment variable

SERVER_NAME The host name and IP address when the CGI script is running.
SERVER_SOFTWARE The type of your server, such as: CERN/3.0 or NCSA/1.3. The CGI version that
GATEWAY_INTERFACE runs. For UNIX servers, this is CGI/1.1. The HTTP protocol that the
SERVER_PROTOCOL server runs. This is HTTP/1.0. The TCP port where the
SERVER_PORT server is running, usually the web server is 80.
REQUEST_METHOD POST or GET, depending on how your form is submitted.
HTTP_ACCEPT browser can directly receive the content-types, there can be HTTP Accept Header definition.
HTTP_USER_AGENT The name, version and other platform-specific additional information of the browser that submits the form.
HTTP_REFERER is the URL of the text for submitting the form. Not all browsers send out this information. Do not rely on the path information attached to
PATH_INFO. It is sent by the browser through the GET method.
PATH_TRANSLATED is the path information specified by the system in PATH_INFO.
SCRIPT_NAME points to this CGI script The path is displayed in the URL (e.g., /cgi-bin/thescript).
QUERY_STRINGScript parameter or form input (if submitted by GET). QUERY_STRING contains the parameter after the question mark in the URL.
REMOTE_HOST is the host name of the script submitted. This value cannot be set.
REMOTE_ADDR is the IP address of the host that submits the script .
REMOTE_USER is the username of the user who submits the script . If the authentication of the server is activated, this value can be set.
REMOTE_IDENT If the web server is running on ident (a protocol that confirms that users connect to you), and the system that submits the form is also running ident, this variable contains the return value of ident.
CONTENT_TYPE If the form is submitted by POST, this value will be application/ x-www-form-urlencoded. In the file upload form, content-type is a multipart/form-data.
CONTENT_LENGTH is the number of bytes of the standard input port for the form submitted by POST.