diff -r 74d3dc78f0db Lib/pydoc.py
--- a/Lib/pydoc.py	Mon Mar 21 13:26:24 2011 +0100
+++ b/Lib/pydoc.py	Tue Mar 29 14:22:39 2011 +0200
@@ -1347,6 +1347,8 @@
 
 def getpager():
     """Decide what method to use for paging through text."""
+    if not hasattr(sys.stdin, "isatty"):
+        return plainpager
     if not hasattr(sys.stdout, "isatty"):
         return plainpager
     if not sys.stdin.isatty() or not sys.stdout.isatty():