diff --git a/test/Dockerfile-alpine b/test/Dockerfile-alpine
index 5b1dbf3..399e10f 100644
--- a/test/Dockerfile-alpine
+++ b/test/Dockerfile-alpine
@@ -18,4 +18,4 @@ RUN /bats-core/install.sh /usr/local
 
 # Use supervisord to run nginx in the background
 COPY ./test/test-config/alpine-supervisord.conf /etc/supervisord.conf
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-centos6 b/test/Dockerfile-centos6
index 108add0..66cc468 100644
--- a/test/Dockerfile-centos6
+++ b/test/Dockerfile-centos6
@@ -23,4 +23,4 @@ RUN /bats-core/install.sh /usr/local
 EXPOSE 80 443
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-centos7-staging b/test/Dockerfile-centos7-staging
index abb697c..f3d985b 100644
--- a/test/Dockerfile-centos7-staging
+++ b/test/Dockerfile-centos7-staging
@@ -24,4 +24,4 @@ RUN /bats-core/install.sh /usr/local
 EXPOSE 80 443
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-debian b/test/Dockerfile-debian
index 6da08d5..640f069 100644
--- a/test/Dockerfile-debian
+++ b/test/Dockerfile-debian
@@ -16,4 +16,4 @@ RUN git clone --depth 1 https://github.com/bats-core/bats-assert /bats-assert
 RUN /bats-core/install.sh /usr/local
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-ubuntu b/test/Dockerfile-ubuntu
index 21169ea..953c3bf 100644
--- a/test/Dockerfile-ubuntu
+++ b/test/Dockerfile-ubuntu
@@ -22,4 +22,4 @@ RUN git clone --depth 1 https://github.com/bats-core/bats-assert /bats-assert
 RUN /bats-core/install.sh /usr/local
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-ubuntu-staging b/test/Dockerfile-ubuntu-staging
index 15d5a59..8fc3455 100644
--- a/test/Dockerfile-ubuntu-staging
+++ b/test/Dockerfile-ubuntu-staging
@@ -26,4 +26,4 @@ RUN git clone --depth 1 https://github.com/bats-core/bats-assert /bats-assert
 RUN /bats-core/install.sh /usr/local
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-ubuntu16 b/test/Dockerfile-ubuntu16
index 6b13f68..bb521ff 100644
--- a/test/Dockerfile-ubuntu16
+++ b/test/Dockerfile-ubuntu16
@@ -18,4 +18,4 @@ RUN git clone --depth 1 https://github.com/bats-core/bats-assert /bats-assert
 RUN /bats-core/install.sh /usr/local
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]
diff --git a/test/Dockerfile-ubuntu18 b/test/Dockerfile-ubuntu18
index 0979cab..98b71af 100644
--- a/test/Dockerfile-ubuntu18
+++ b/test/Dockerfile-ubuntu18
@@ -23,4 +23,4 @@ RUN /bats-core/install.sh /usr/local
 EXPOSE 80 443
 
 # Run eternal loop - for testing
-CMD tail -f /dev/null
+CMD [ "tail", "-f", "/dev/null" ]