diff --git a/app.rb b/app.rb
index da36400..9cd48b7 100644
--- a/app.rb
+++ b/app.rb
@@ -444,7 +444,13 @@ end
 
 get "/_cat/env" do
   stream do |out|
-    ENV.sort.each do |k, v|
+    e = if params.key? :rack
+      env
+    else
+      ENV
+    end
+
+    e.sort.each do |k, v|
       out << "#{k}=#{v}\n"
     end
   end