diff --git a/tools/install_venv.py b/tools/install_venv.py
index a05f1dea..4648058d 100644
--- a/tools/install_venv.py
+++ b/tools/install_venv.py
@@ -37,7 +37,7 @@ def print_help():
     To activate the Karbor virtualenv for the extent of your current shell
     session you can run:
 
-    $ source .venv/bin/activate
+    $ . .venv/bin/activate
 
     Or, if you prefer, you can run commands in the virtualenv on a case by case
     basis by running: