The following is just a sampling in the use of server side includes. This sampling demonstrates the use of CGI Environment Variables using the #echo Server Side Includes.

In order to pass data about the information request from the server to the script, the server uses command line arguments as well as environment variables. These environment variables are set when the server executes the gateway program.

Some server configurations require the file containing SSI commands to end with .shtml whereas others do not. You should check with your system administrator concerning whether they support SSI. In many cases you can put the following in your .htaccess document which resides in your root directory:

AddHandler server-parsed .html
AddType text/html shtml

1. This variable is the complete local directory path of the current document.
   <!--#echo var="DOCUMENT_NAME" -->
   : ssi.html

2. This web page file size.
   <!--#config sizefmt="bytes" --><!--#fsize file="ssi.html" -->
   : [an error occurred while processing this directive]
   <!--#config sizefmt="abbrev" --><!--#fsize file="ssi.html" -->
   : [an error occurred while processing this directive]

3. This variable is the local path of the current document referenced to the base directory of the web space.
   <!--#echo var="DOCUMENT_URI" -->
   : /books/ssi.html

4. This variable is the unescaped query string sent by the client browser with all shell-special characters replaced with local system equivalents.
   <!--#echo var="QUERY_STRING_UNESCAPED" -->
   : (none)

5. This variable is the date and time of the last modification of the current document.
   <!--#echo var="LAST_MODIFIED" -->
   : Sunday, 30-May-2004 00:01:03 CDT

6. This variable is the IP address of the remote client browser.
   <!--#echo var="REMOTE_ADDR" -->
   : 38.107.179.207

7. This variable is the raw query string sent from the remote browser.
   <!--#echo var="QUERY_STRING" -->
   :

8. This variable is the name of the HTTP server software.
   <!--#echo var="SERVER_SOFTWARE" -->
   : Apache

9. This variable is the local computer name of the HTTP server.
   <!--#echo var="SERVER_NAME" -->
   : www.microcaddesign.com

10. This variable is the name/version of the Common Gateway Interface served on this HTTP server.
    <!--#echo var="GATEWAY_INTERFACE" -->
    : CGI/1.1

11. This variable is the name/version of HTTP served on this HTTP server
    <!--#echo var="SERVER_PROTOCOL" -->
    : HTTP/1.1

12. This variable is the IP port the HTTP server is answering on.
    <!--#echo var="SERVER_PORT" -->
    : 80

13. This variable is the method by which the current document was requested.
    <!--#echo var="REQUEST_METHOD" -->
    : GET

14. This variable is the extra path info that is sent.
    <!--#echo var="PATH_INFO" -->
    : (none)

15. This variable is the 'PATH_INFO' with all shell-special characters replaced with local system equivalents.
    <!--#echo var="PATH_TRANSLATED" -->
    : (none)

16. This variable is the virtual path of the script being executed.
    <!--#echo var="SCRIPT_NAME" -->
    : /books/ssi.html

17. This variable is the host name of the remote client.
    <!--#echo var="REMOTE_HOST" -->
    : (none)

18. This variable is the authentication method used to validate the remote client.
    <!--#echo var="AUTH_TYPE" -->
    : (none)

19. This variable is the user name used to validate authentication from the remote client.
    <!--#echo var="REMOTE_USER" -->
    : (none)

20. This variable is the remote user name if supporting RFC931 identification.
    <!--#echo var="REMOTE_IDENT" -->
    : (none)

21. This variable is the content type of the attached information in the case of a POST or PUT.
    <!--#echo var="CONTENT_TYPE" -->
    : (none)

22. This variable is the length of the attached information in the case of a POST or PUT.
    <!--#echo var="CONTENT_LENGTH" -->
    : (none)

23. This variable is a comma separated list of mime types that are accepted by the remote browser.
    <!--#echo var="HTTP_ACCEPT" -->
    : text/html,application/xhtml+xml,text/xml;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5

24. This variable is the name of the remote client browser software.
    <!--#echo var="HTTP_USER_AGENT" -->
    : CCBot/1.0 (+http://www.commoncrawl.org/bot.html)

25. This variable is the URL of the HTML document which referred the remote client to this document.
    <!--#echo var="HTTP_REFERER" -->
    : (none)

26. This variable is the name (most likely the-mail address) of the remote client user.
    <!--#echo var="FROM" -->
    : (none)

27. This variable is the name of the proxy server through which this document is being processed.
    <!--#echo var="FORWARDED" -->
    : (none)

28. This variable lists the human languages that are acceptable to the remote client.
    <!--#echo var="ACCEPT_LANGUGE" -->
    : (none)

29. This variable contains the cookie sent by the remote client.
    <!--#echo var="HTTP_COOKIE" -->
    : (none)

30. Number of accesses to current document since server was brought on line.
    <!--#echo var="PAGE_COUNT" -->
    : (none)

31. Total pages served by server since brought on line.
    <!--#echo var="TOTAL_HITS" -->
    : (none)

32. Executes a given shell command or CGI script. It must be activated to be used.
    <!--#exec cmd="ls -l" -->
    :