diff --git a/.github/workflows/verifyimage.yml b/.github/workflows/verifyimage.yml
index 7467a4e..9de7b95 100644
--- a/.github/workflows/verifyimage.yml
+++ b/.github/workflows/verifyimage.yml
@@ -78,7 +78,7 @@ jobs:
       - name: Verify ${{ matrix.target }}
         run: |
           [ $(docker inspect ${{ matrix.target }}-test --format='{{.State.Running}}') = 'true' ]
-          if grep -q  "nginx <<< ${{ matrix.target }}" ; then
+          if grep -q  "nginx "<<< "${{ matrix.target }}"; then
             curl -q -D headers.txt http://localhost:8080/?test=../../etc/passwd
             grep -q "HTTP/1.1 403 Forbidden" headers.txt
             grep -q "Access-Control-Allow-Origin: *" headers.txt
diff --git a/nginx/Dockerfile b/nginx/Dockerfile
index ced432a..98f146a 100644
--- a/nginx/Dockerfile
+++ b/nginx/Dockerfile
@@ -57,16 +57,17 @@ RUN set -eux; \
 
 # Build modules
 RUN set -eux; \
+    declare -a modules; \
     for module in ${NGINX_DYNAMIC_MODULES}; \
     do; \
-        repo=$(awk -F'/' '{print $2}' <<< $module); \
+        repo=$(awk -F'/' '{print $2}' <<< "${module}"); \
         git clone -b master --depth 1 https://github.com/${module}.git; \
-        modules=+("--add-dynamic-module=../${repo}"); \
+        modules+=("--add-dynamic-module=../${repo}"); \
     done; \
     curl -sSL https://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz -o nginx-${NGINX_VERSION}.tar.gz; \
     tar -xzf nginx-${NGINX_VERSION}.tar.gz; \
     cd ./nginx-${NGINX_VERSION}; \
-    ./configure --with-compat ${modules[@]} ;\
+    ./configure --with-compat ${modules[@]}; \
     make modules; \
     strip objs/*.so; \
     cp objs/*.so /etc/nginx/modules/; \
diff --git a/nginx/Dockerfile-alpine b/nginx/Dockerfile-alpine
index 2a2fc34..3d7981c 100644
--- a/nginx/Dockerfile-alpine
+++ b/nginx/Dockerfile-alpine
@@ -53,16 +53,17 @@ RUN set -eux; \
 
    # Build modules
 RUN set -eux; \
+    declare -a modules;
     for module in ${NGINX_DYNAMIC_MODULES}; \
     do; \
-        repo=$(awk -F'/' '{print $2}' <<< $module); \
+        repo=$(awk -F'/' '{print $2}' <<< "${module}"); \
         git clone -b master --depth 1 https://github.com/${module}.git; \
-        modules=+("--add-dynamic-module=../${repo}"); \
+        modules+=("--add-dynamic-module=../${repo}"); \
     done; \
     curl -sSL https://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz -o nginx-${NGINX_VERSION}.tar.gz; \
     tar -xzf nginx-${NGINX_VERSION}.tar.gz; \
     cd ./nginx-${NGINX_VERSION}; \
-    ./configure --with-compat ${modules[@]} ;\
+    ./configure --with-compat ${modules[@]};\
     make modules; \
     strip objs/*.so; \
     cp objs/*.so /etc/nginx/modules/; \