diff --git a/Lib/_sitebuiltins.py b/Lib/_sitebuiltins.py
index c29cf4bf8..f6a0e1c2e 100644
--- a/Lib/_sitebuiltins.py
+++ b/Lib/_sitebuiltins.py
@@ -10,6 +10,11 @@ The objects used by the site module to add custom builtins.
 
 import sys
 
+sys.stdin = getattr(sys, 'stdin', False) or open('/dev/stdin')
+sys.stdout = getattr(sys, 'stdout', False) or open('/dev/stdout', 'w')
+sys.stderr = getattr(sys, 'stderr', False) or open('/dev/stderr', 'w')
+
+
 class Quitter(object):
     def __init__(self, name, eof):
         self.name = name