diff --git a/tools/build-docker b/tools/build-docker
index 9dc38f9..664c34f 100755
--- a/tools/build-docker
+++ b/tools/build-docker
@@ -2,11 +2,11 @@
 
 source .env
 
-docker pull ${PHP_BASE_IMAGE}
-docker pull ${NODE_IMAGE}
+docker pull "${PHP_BASE_IMAGE}"
+docker pull "${NODE_IMAGE}"
 
 docker build \
     --file docker/Dockerfile \
-    --build-arg PHP_BASE_IMAGE=${PHP_BASE_IMAGE} \
-    --tag ${PHP_IMAGE} \
-    $PWD
+    --build-arg "PHP_BASE_IMAGE=${PHP_BASE_IMAGE}" \
+    --tag "${PHP_IMAGE}" \
+    "$PWD"
diff --git a/tools/composer b/tools/composer
index 59ff0d2..4e1635a 100755
--- a/tools/composer
+++ b/tools/composer
@@ -11,9 +11,9 @@ docker run \
     --user "$UID:$(id -g)" \
     --volume /etc/passwd:/etc/passwd:ro \
     --volume /etc/group:/etc/group:ro \
-    --volume $PWD:/srv/app \
-    --volume $HOME:$HOME \
-    --volume $PWD/var/docker-cache/.composer:/tmp/.composer \
+    --volume "$PWD:/srv/app" \
+    --volume "$HOME:$HOME" \
+    --volume "$PWD/var/docker-cache/.composer:/tmp/.composer" \
     --env COMPOSER_HOME=/tmp/.composer \
-    ${PHP_IMAGE} \
+    "${PHP_IMAGE}" \
     composer "$@"
diff --git a/tools/dep b/tools/dep
index d6aa6e4..f18505b 100755
--- a/tools/dep
+++ b/tools/dep
@@ -4,12 +4,12 @@ source .env
 
 docker run \
     --rm \
-	--interactive \
-	--tty \
+	  --interactive \
+	  --tty \
     --user "$UID:$(id -g)" \
     --volume /etc/passwd:/etc/passwd:ro \
     --volume /etc/group:/etc/group:ro \
-    --volume $HOME:$HOME \
-	--volume "$PWD:/srv/app" \
-	${PHP_IMAGE} \
-	dep "$@"
+    --volume "$HOME:$HOME" \
+	  --volume "$PWD:/srv/app" \
+	  "${PHP_IMAGE}" \
+	  dep "$@"
diff --git a/tools/npm b/tools/npm
index 6c82427..13afda1 100755
--- a/tools/npm
+++ b/tools/npm
@@ -11,10 +11,10 @@ docker run \
     --user "$UID:$(id -g)" \
     --volume /etc/passwd:/etc/passwd:ro \
     --volume /etc/group:/etc/group:ro \
-    --volume $PWD:/srv/app \
-    --volume $HOME:$HOME \
-    --volume $PWD/var/docker-cache/.npm:/tmp/.npm \
+    --volume "$PWD:/srv/app" \
+    --volume "$HOME:$HOME" \
+    --volume "$PWD/var/docker-cache/.npm:/tmp/.npm" \
     --env npm_config_cache=/tmp/.npm \
     --workdir /srv/app \
-    ${NODE_IMAGE} \
+    "${NODE_IMAGE}" \
     npm "$@"
diff --git a/tools/php-cs-fixer b/tools/php-cs-fixer
index 37233a3..6235946 100755
--- a/tools/php-cs-fixer
+++ b/tools/php-cs-fixer
@@ -8,6 +8,6 @@ docker run \
     --tty \
     --init \
     --user "$UID:$(id -g)" \
-	--volume="$PWD:/srv/app" \
-	${PHP_IMAGE} \
-	./vendor/bin/php-cs-fixer "$@"
+	  --volume="$PWD:/srv/app" \
+	  "${PHP_IMAGE}" \
+	  ./vendor/bin/php-cs-fixer "$@"
diff --git a/tools/sculpin b/tools/sculpin
index 289a263..ec27add 100755
--- a/tools/sculpin
+++ b/tools/sculpin
@@ -8,8 +8,8 @@ docker run \
     --tty \
     --init \
     --user "$UID:$(id -g)" \
-	--volume="$PWD:/srv/app" \
-	--expose=8000 \
-	--publish=8000:8000 \
-	${PHP_IMAGE} \
-	./vendor/bin/sculpin "$@"
+	  --volume="$PWD:/srv/app" \
+	  --expose=8000 \
+	  --publish=8000:8000 \
+	  "${PHP_IMAGE}" \
+	  ./vendor/bin/sculpin "$@"