diff --git a/Dockerfile b/Dockerfile
index c67def1e..f4d7b5fc 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -56,7 +56,7 @@ RUN useradd -ms /bin/bash stolon
 RUN mkdir -p /run/haproxy/
 COPY --from=flyutil /fly/bin/* /usr/local/bin/
 
-ENV ENV="/fly/set-stolon-environment.sh"
+ENV ENV="/fly/shell-init"
 
 EXPOSE 5432
 
diff --git a/scripts/set-stolon-environment.sh b/scripts/set-stolon-environment.sh
deleted file mode 100755
index 1bcc6538..00000000
--- a/scripts/set-stolon-environment.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/sh
-
-if [ -f /data/.env ]; then
-  export $(cat /data/.env)
-fi
diff --git a/scripts/shell-init b/scripts/shell-init
new file mode 100755
index 00000000..898b164b
--- /dev/null
+++ b/scripts/shell-init
@@ -0,0 +1,11 @@
+#!/bin/dash
+# Dash sources this file according to POSIX envvar $ENV declared in Dockerfile
+# https://manpages.debian.org/stretch/dash/dash.1.en.html#Invocation
+
+if [ -f /data/.env ]; then
+  export $(cat /data/.env)
+fi
+
+# Upgrade to Bash shell
+unset ENV
+exec /bin/bash "$@"