diff --git a/debian4isabelle/Dockerfile b/debian4isabelle/Dockerfile
index c475cc7..8229da1 100644
--- a/debian4isabelle/Dockerfile
+++ b/debian4isabelle/Dockerfile
@@ -26,7 +26,7 @@
 
 FROM debian:testing-slim
 
-SHELL ["/bin/bash", "-c"]
+# SHELL ["/bin/bash", "-c"]
 
 # packages
 RUN apt-get -y update && \
diff --git a/isabelle/Dockerfile b/isabelle/Dockerfile
index 867d914..fce5e37 100644
--- a/isabelle/Dockerfile
+++ b/isabelle/Dockerfile
@@ -34,7 +34,7 @@ LABEL isabelle.url="$isabelle"
 LABEL isabelle.afp.url="$afp"
 LABEL isabelle.sessions="$sessions"
 
-SHELL ["/bin/bash", "-c"]
+# SHELL ["/bin/bash", "-c"]
 
 # Create default user (isabelle)
 RUN useradd -m isabelle && (echo isabelle:isabelle | chpasswd)