diff --git a/build-docker.sh b/build-docker.sh
index 4808691..c8fab5e 100755
--- a/build-docker.sh
+++ b/build-docker.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -eu
 
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 3796e26..ad4678e 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -3,7 +3,6 @@
 #    `docker run --rm -it -v $(pwd):$(pwd) -w $(pwd) stowtest`
 FROM debian:jessie
 RUN DEBIAN_FRONTEND=noninteractive \
-apt-get clean && \
 apt-get update -qq && \
 apt-get install -y -q \
     autoconf \
@@ -18,6 +17,7 @@ apt-get install -y -q \
     texinfo \
     texlive \
     texi2html \
+&& apt-get clean \
 && rm -rf /var/lib/apt/lists/*
 
 # Set up perlbrew
diff --git a/test-docker.sh b/test-docker.sh
index 2bedcae..81e820e 100755
--- a/test-docker.sh
+++ b/test-docker.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # Test Stow across multiple Perl versions, by executing the
 # Docker image built via build-docker.sh.