diff --git a/lib/rdoc/README b/lib/rdoc/README
index 1b8671182f..0c10d0ea69 100644
--- a/lib/rdoc/README
+++ b/lib/rdoc/README
@@ -196,11 +196,12 @@ Options are:
 [<tt>--quiet</tt>]
     do not display progress messages
 
-[<tt>--ri</tt> _and_ <tt>--ri-site</tt>]
+[<tt>--ri</tt>, <tt>--ri-site</tt>, _and_ <tt>--ri-system</tt>]
     generate output than can be read by the _ri_ command-line tool.
-    By default --ri places its output in ~/.rdoc, and --ri-site in
-    $datadir/ri/<ver>/site. Both can be overridden with a subsequent
-    --op option. Both default directories are in ri's default search
+    By default --ri places its output in ~/.rdoc, --ri-site in
+    $datadir/ri/<ver>/site, and --ri-system in
+    $datadir/ri/<ver>/system. All can be overridden with a subsequent
+    --op option. All default directories are in ri's default search
     path.
 
 [<tt>--show-hash</tt>]
diff --git a/lib/rdoc/options.rb b/lib/rdoc/options.rb
index ab99c18b86..0d99a5438e 100644
--- a/lib/rdoc/options.rb
+++ b/lib/rdoc/options.rb
@@ -198,6 +198,12 @@ class Options
        "stored in a site-wide directory, making them accessible\n"+
        "to others, so special privileges are needed." ],
 
+      [ "--ri-system",     "-Y",   nil,
+       "generate output for use by 'ri.' The files are\n" +
+       "stored in a system-level directory, making them accessible\n"+
+       "to others, so special privileges are needed. This option\n"+
+       "is intended to be used during Ruby installations" ],
+
       [ "--show-hash",     "-H",   nil,
         "A name of the form #name in a comment\n" +
         "is a possible hyperlink to an instance\n" +
@@ -431,9 +437,14 @@ class Options
         when "--include"   
           @rdoc_include.concat arg.split(/\s*,\s*/)
 
-        when "--ri", "--ri-site"
+        when "--ri", "--ri-site", "--ri-system"
           @generator_name = "ri"
-          @op_dir = opt == "--ri" ? RI::Paths::HOMEDIR : RI::Paths::SITEDIR
+          @op_dir = case opt
+                    when "--ri" then RI::Paths::HOMEDIR 
+                    when "--ri-site" then RI::Paths::SITEDIR
+                    when "--ri-system" then RI::Paths::SYSDIR
+                    else fail opt
+                    end
           setup_generator(generators)
 
         when "--tab-width"