diff --git a/letsencrypt-auto-source/Dockerfile.redhat6 b/letsencrypt-auto-source/Dockerfile.redhat6
index dead3e0d5..02439da3a 100644
--- a/letsencrypt-auto-source/Dockerfile.redhat6
+++ b/letsencrypt-auto-source/Dockerfile.redhat6
@@ -51,4 +51,4 @@ RUN cp /home/lea/certbot/letsencrypt-auto-source/tests/${REDHAT_DIST_FLAVOR}6_te
 USER lea
 WORKDIR /home/lea
 
-CMD ["sudo", "script -c certbot/letsencrypt-auto-source/tests/redhat6_tests.sh"]
+CMD ["sudo", "script", "-c", "certbot/letsencrypt-auto-source/tests/redhat6_tests.sh"]