diff --git a/tools/run_tests/jobset.py b/tools/run_tests/jobset.py
index 8694b8f6bd7c33e34ef2bbae46a66217dd1f3f4c..baa126ba5f6b909aa152ec1acb77133b30338597 100755
--- a/tools/run_tests/jobset.py
+++ b/tools/run_tests/jobset.py
@@ -95,7 +95,7 @@ def message(tag, msg, explanatory_text=None, do_newline=False):
     return
   message.old_tag = tag
   message.old_msg = msg
-  if platform.system() == 'Windows':
+  if platform.system() == 'Windows' or not sys.stdout.isatty():
     if explanatory_text:
       print explanatory_text
     print '%s: %s' % (tag, msg)