diff -r 302df09a6aa8 Lib/idlelib/PyShell.py
--- a/Lib/idlelib/PyShell.py	Wed Jul 11 09:17:15 2012 +0200
+++ b/Lib/idlelib/PyShell.py	Wed Jul 11 09:23:21 2012 +0200
@@ -12,6 +12,7 @@
 import tokenize
 import traceback
 import types
+import io
 
 import linecache
 from code import InteractiveInterpreter
@@ -410,7 +411,7 @@
         except socket.timeout as err:
             self.display_no_subprocess_error()
             return None
-        self.rpcclt.register("stdin", self.tkconsole)
+        self.rpcclt.register("stdin", self.tkconsole.stdin)
         self.rpcclt.register("stdout", self.tkconsole.stdout)
         self.rpcclt.register("stderr", self.tkconsole.stderr)
         self.rpcclt.register("flist", self.tkconsole.flist)
@@ -850,13 +851,14 @@
         self.save_stderr = sys.stderr
         self.save_stdin = sys.stdin
         from idlelib import IOBinding
+        self.stdin = PseudoInputFile(self)
         self.stdout = PseudoFile(self, "stdout", IOBinding.encoding)
         self.stderr = PseudoFile(self, "stderr", IOBinding.encoding)
         self.console = PseudoFile(self, "console", IOBinding.encoding)
         if not use_subprocess:
             sys.stdout = self.stdout
             sys.stderr = self.stderr
-            sys.stdin = self
+            sys.stdin = self.stdin
         try:
             # page help() text to shell.
             import pydoc # import must be done here to capture i/o rebinding.
@@ -1256,6 +1258,15 @@
     def isatty(self):
         return True
 
+class PseudoInputFile(object):
+    def __init__(self, shell):
+        self.readline = shell.readline
+        self.isatty = shell.isatty
+
+    def write(self, s):
+        raise io.UnsupportedOperation("not writable")
+    writelines = write
+
 
 usage_msg = """\
 
diff -r 302df09a6aa8 Lib/idlelib/run.py
--- a/Lib/idlelib/run.py	Wed Jul 11 09:17:15 2012 +0200
+++ b/Lib/idlelib/run.py	Wed Jul 11 09:23:21 2012 +0200
@@ -264,20 +264,28 @@
     def __setattr__(self, name, value):
         return setattr(self.rpc, name, value)
 
+class _RPCOutputFile(_RPCFile):
     def write(self, s):
         if not isinstance(s, str):
             raise TypeError('must be str, not ' + type(s).__name__)
         return self.rpc.write(s)
 
+class _RPCInputFile(_RPCFile):
+    # XXX The remote file will raise the same exception. Unfortunately,
+    # the RPC library doesn't support marshalling exceptions yet.
+
+    def write(self, s):
+        raise io.UnsupportedOperation("not writable")
+
 class MyHandler(rpc.RPCHandler):
 
     def handle(self):
         """Override base method"""
         executive = Executive(self)
         self.register("exec", executive)
-        sys.stdin = self.console = self.get_remote_proxy("stdin")
-        sys.stdout = _RPCFile(self.get_remote_proxy("stdout"))
-        sys.stderr = _RPCFile(self.get_remote_proxy("stderr"))
+        sys.stdin = self.console = _RPCInputFile(self.get_remote_proxy("stdin"))
+        sys.stdout = _RPCOutputFile(self.get_remote_proxy("stdout"))
+        sys.stderr = _RPCOutputFile(self.get_remote_proxy("stderr"))
         # page help() text to shell.
         import pydoc # import must be done here to capture i/o binding
         pydoc.pager = pydoc.plainpager