env vars for server side includes?

From: ellson@hotsand.att.com
Date: Sat, 2 Oct 93 13:42:14 EDT
Original-From: hotsand!ellson (John Ellson)
Message-id: <9310021742.AA20293@hotsand.dacsand>
To: www-talk@nxoc01.cern.ch
Subject: env vars for server side includes?
This question is primarily for the ncsa-httpd developers, but also
for Tony Sanders if he would consider implementing server side
includes into plexus.

I'd like to put the last-modified date of the html file into the display.
Is there a way to obtain the full pathname of the current html file to pass 
to a program?

I'm thinking perhaps an environment variable set by the server 
daemon so that I can do something like:

  Last modified: <inc srv "|ls -l $HTML_PATHNAME |awk '{print $5,$6,$7}'>

Some other possibly useful environment variables that come to mind are the
identity and version of the server daemon.