diff --git a/tox.ini b/tox.ini
index 7f876d1f60..3436eba711 100644
--- a/tox.ini
+++ b/tox.ini
@@ -76,9 +76,10 @@ commands =
 # we do not used -W here because we are doing some slightly tricky
 # things to build a single page document, and as such, we are ok
 # ignoring the duplicate stanzas warning.
+whitelist_externals = bash
 install_command = pip install -U --force-reinstall {opts} {packages}
 commands =
-  rm -rf api-ref/build
+  bash -c 'rm -rf api-ref/build'
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
 
 [testenv:releasenotes]