diff --git a/IPython/terminal/ptutils.py b/IPython/terminal/ptutils.py
index 3cf3c11..7679b4a 100644
--- a/IPython/terminal/ptutils.py
+++ b/IPython/terminal/ptutils.py
@@ -20,6 +20,7 @@ from prompt_toolkit.patch_stdout import patch_stdout
 
 import pygments.lexers as pygments_lexers
 import os
+import sys
 
 _completion_sentinel = object()