diff --git a/collects/readline/doc.txt b/collects/readline/doc.txt
index 5720d10552..c68bafbcce 100644
--- a/collects/readline/doc.txt
+++ b/collects/readline/doc.txt
@@ -11,16 +11,21 @@ The _rep.ss_ library installs a readline-based input port, and hooks
 the prompt-and-read part of MzScheme's read-eval-print loop to
 interact with it.
 
-You can put the following in your ~/.mzschemerc so that MzScheme
-starts with readline support on xterms:
-
-  (when (regexp-match? #rx"xterm" (getenv "TERM"))
-    (dynamic-require '(lib "rep.ss" "readline") #f))
-
-or start MzScheme with
+You can start MzScheme with
 
   mzscheme -L rep.ss readline
 
+or you can put the following in your ~/.mzschemerc so that MzScheme
+starts with readline support when appropriate:
+
+  (when (and (regexp-match? #rx"xterm" (getenv "TERM"))
+             (terminal-port? (current-input-port)))
+    (dynamic-require '(lib "rep.ss" "readline") #f))
+
+(The first condition rules out running in dumb terminals, eg, inside
+Emacs, and the second condition avoids using it when input is
+redirected.)
+
 The readline history is stored across invocations in MzScheme's
 preferences file, assuming MzScheme exits normally.