diff -wur bash-4.1/bash/lib/readline/display.c bash-4.1.N/bash/lib/readline/display.c
--- bash-4.1/bash/lib/readline/display.c	2009-09-26 11:37:33.000000000 -0700
+++ bash-4.1.N/bash/lib/readline/display.c	2010-06-14 22:54:30.000000000 -0700
@@ -65,6 +65,8 @@
 static void insert_some_chars PARAMS((char *, int, int));
 static void cr PARAMS((void));
 
+int _rl_extproc;
+
 /* State of visible and invisible lines. */
 struct line_state
   {
@@ -728,6 +730,8 @@
      It maintains an array of line breaks for display (inv_lbreaks).
      This handles expanding tabs for display and displaying meta characters. */
   lb_linenum = 0;
+  if (_rl_extproc) goto do_ext;
+
 #if defined (HANDLE_MULTIBYTE)
   in = 0;
   if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
@@ -902,6 +906,7 @@
 #endif
 
     }
+do_ext:
   line[out] = '\0';
   if (cpos_buffer_position < 0)
     {
diff -wur bash-4.1/bash/lib/readline/rlprivate.h bash-4.1.N/bash/lib/readline/rlprivate.h
--- bash-4.1/bash/lib/readline/rlprivate.h	2009-08-31 05:46:04.000000000 -0700
+++ bash-4.1.N/bash/lib/readline/rlprivate.h	2010-06-14 22:20:03.000000000 -0700
@@ -396,6 +396,7 @@
 extern int _rl_last_c_pos;
 extern int _rl_suppress_redisplay;
 extern int _rl_want_redisplay;
+extern int _rl_extproc;
 
 /* isearch.c */
 extern char *_rl_isearch_terminators;
diff -wur bash-4.1/bash/lib/readline/rltty.c bash-4.1.N/bash/lib/readline/rltty.c
--- bash-4.1/bash/lib/readline/rltty.c	2009-11-19 06:42:02.000000000 -0800
+++ bash-4.1.N/bash/lib/readline/rltty.c	2010-06-14 22:18:32.000000000 -0700
@@ -521,6 +521,12 @@
   _rl_echoctl = (oldtio.c_lflag & ECHOCTL);
 #endif
 
+  if (oldtio.c_lflag & EXTPROC) {
+    tiop->c_cc[VEOL] = 9;	/* TAB */
+	_rl_extproc = 1;
+	return;
+  }
+
   tiop->c_lflag &= ~(ICANON | ECHO);
 
   if ((unsigned char) oldtio.c_cc[VEOF] != (unsigned char) _POSIX_VDISABLE)
diff -wur bash-4.1/bash/lib/readline/text.c bash-4.1.N/bash/lib/readline/text.c
--- bash-4.1/bash/lib/readline/text.c	2009-09-07 10:40:57.000000000 -0700
+++ bash-4.1.N/bash/lib/readline/text.c	2010-06-14 23:22:02.000000000 -0700
@@ -971,7 +971,7 @@
   if (rl_erase_empty_line && rl_point == 0 && rl_end == 0)
     return 0;
 
-  if (_rl_echoing_p)
+  if (_rl_echoing_p && !_rl_extproc)
     _rl_update_final ();
   return 0;
 }