diff --git a/developer/bootstrap-repo.sh b/developer/bootstrap-repo.sh
index bd41e59..0351da7 100755
--- a/developer/bootstrap-repo.sh
+++ b/developer/bootstrap-repo.sh
@@ -73,7 +73,7 @@
   repo sync
 
   # download gerrit patches using repo
-  if [[ ! -z "${GERRIT_PATCHES[*]-}" ]]
+  if [[ -n "${GERRIT_PATCHES[*]-}" ]]
   then
     for gerrit_patch in "${GERRIT_PATCHES[@]-}"
     do
diff --git a/developer/tag_and_push.sh b/developer/tag_and_push.sh
index 8366687..a2bdec5 100755
--- a/developer/tag_and_push.sh
+++ b/developer/tag_and_push.sh
@@ -108,12 +108,12 @@
 fi
 
 # Filter images
-if [[ ! -z "$filter" ]]
+if [[ -n "$filter" ]]
 then
   images=$(echo -e "${images}" | grep -E "${filter}")
 fi
 
-if [[ ! -z "$registry" ]]
+if [[ -n "$registry" ]]
 then
   images=$(echo "${images}" | grep -v "${registry}")
 fi
@@ -122,7 +122,7 @@
   new_image=""
 
   # Set registry
-  if [[ ! -z "$registry" ]]
+  if [[ -n "$registry" ]]
   then
     new_image+="${registry}/"
   else
diff --git a/developer/update_xos_docker.sh b/developer/update_xos_docker.sh
index 6fa2146..29d2a64 100755
--- a/developer/update_xos_docker.sh
+++ b/developer/update_xos_docker.sh
@@ -35,7 +35,7 @@
 XOS_VERSION=$(cat "${WORKSPACE}/cord/orchestration/xos/VERSION")
 
 # Update Synchronizer FROM parent versions
-for df in ${WORKSPACE}/cord/orchestration/xos_services/*/Dockerfile.synchronizer
+for df in "${WORKSPACE}"/cord/orchestration/xos_services/*/Dockerfile.synchronizer
 do
   df_contents=$(cat "$df")
 
@@ -74,8 +74,8 @@
 done
 
 # Update XOS parent versions
-for df in ${WORKSPACE}/cord/orchestration/xos/containers/*/Dockerfile* \
-          ${WORKSPACE}/cord/orchestration/xos-tosca/Dockerfile
+for df in "${WORKSPACE}"/cord/orchestration/xos/containers/*/Dockerfile* \
+          "${WORKSPACE}/cord/orchestration/xos-tosca/Dockerfile"
 do
   echo "Updating core Dockerfile: ${df}"
   perl -pi -e "s/^FROM xos(.*):.*$/FROM xos\\1:$XOS_VERSION/" "$df"