Make a start on explaining the two kinds of "environment variables"

that Apache deals with.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@911499 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/env.xml b/docs/manual/env.xml
index b856230f8ab2d517bfa155da56d22b53715de4dc..88270bf43acb671fafe56f1b7162e1be92db9326 100644 (file)
--- a/docs/manual/env.xml
+++ b/docs/manual/env.xml
@@ -25,8 +25,17 @@
   <title>Environment Variables in Apache</title>
 
   <summary>
-    <p>The Apache HTTP Server provides a mechanism for storing
-    information in named variables that are called <em>environment
+    <p>There are two kinds of environment variables that affect
+    the Apache HTTP Server.</p>
+
+    <p>First, there are the environment variables controlled by
+    the underlying operating system.  These are set before the
+    server starts.  They can be used in expansions in configuration
+    files, and can optionally be passed to CGI scripts and SSI
+    using the PassEnv directive.</p>
+
+    <p>Second, the Apache HTTP Server provides a mechanism for storing
+    information in named variables that are also called <em>environment
     variables</em>. This information can be used to control various
     operations such as logging or access control. The variables are
     also used as a mechanism to communicate with external programs