diff --git a/.templates/00-global_var.sh b/.templates/00-global_var.sh
index c93e39c80..45743d7fc 100644
--- a/.templates/00-global_var.sh
+++ b/.templates/00-global_var.sh
@@ -26,7 +26,7 @@ done
 ################
 # Set timezone #
 ################
-if [ ! -z "TZ" ] && [ -f /etc/localtime ]; then
+if [ -n "TZ" ] && [ -f /etc/localtime ]; then
   if [ -f /usr/share/zoneinfo/"$TZ" ]; then
     echo "Timezone set from $(cat /etc/timezone) to $TZ"
     ln -snf /usr/share/zoneinfo/"$TZ" /etc/localtime && echo "$TZ" >/etc/timezone
diff --git a/arpspoof/rootfs/etc/cont-init.d/99-run.sh b/arpspoof/rootfs/etc/cont-init.d/99-run.sh
index 189fe4877..1e1e35545 100644
--- a/arpspoof/rootfs/etc/cont-init.d/99-run.sh
+++ b/arpspoof/rootfs/etc/cont-init.d/99-run.sh
@@ -1,9 +1,9 @@
 #!/usr/bin/env bashio
 
 # Autodefine if not defined
-if [ ! -z INTERFACE_NAME ]; then
-export INTERFACE_NAME=$(ip route get 8.8.8.8 | sed -nr 's/.*dev ([^\ ]+).*/\1/p')
-bashio::log.blue "Autodetection : INTERFACE_NAME=$INTERFACE_NAME"
+if [ -n INTERFACE_NAME ]; then
+    export INTERFACE_NAME=$(ip route get 8.8.8.8 | sed -nr 's/.*dev ([^\ ]+).*/\1/p')
+    bashio::log.blue "Autodetection : INTERFACE_NAME=$INTERFACE_NAME"
 fi
 
 bashio::log.info "Starting..."
diff --git a/nextcloud/rootfs/etc/cont-init.d/30-keygen.sh b/nextcloud/rootfs/etc/cont-init.d/30-keygen.sh
index 6407eaa9a..f41d265a7 100644
--- a/nextcloud/rootfs/etc/cont-init.d/30-keygen.sh
+++ b/nextcloud/rootfs/etc/cont-init.d/30-keygen.sh
@@ -28,7 +28,7 @@ echo "... adding ssl certs in files"
 for NGINXFILE in "/defaults/default" "/config/nginx/site-confs/default" "/data/config/nginx/site-confs/default"; do
   if [ -f $NGINXFILE ]; then
     LINE=$(sed -n "/ssl_certificate /=" $NGINXFILE)
-    if [ ! -z $LINE ]; then
+    if [ -n $LINE ]; then
       sed -i "/ssl_certificate/ d" $NGINXFILE
       sed -i "$LINE i ssl_certificate_key /ssl/$KEYFILE;" $NGINXFILE
       sed -i "$LINE i ssl_certificate /ssl/$CERTFILE;" $NGINXFILE
diff --git a/nextcloud/rootfs/etc/cont-init.d/99-elasticsearch.sh b/nextcloud/rootfs/etc/cont-init.d/99-elasticsearch.sh
index f95f6b56c..d7da6278b 100644
--- a/nextcloud/rootfs/etc/cont-init.d/99-elasticsearch.sh
+++ b/nextcloud/rootfs/etc/cont-init.d/99-elasticsearch.sh
@@ -32,7 +32,7 @@ if bashio::config.true 'Full_Text_Search'; then
     APPS=(fulltextsearch fulltextsearch_elasticsearch files_fulltextsearch)
     for app in "${APPS[@]}"; do
         # If app exists, remove it
-        [ ! -z $($LAUNCHER app:getpath $app) ] && $LAUNCHER app:remove $app &>/dev/null
+        [ -n $($LAUNCHER app:getpath $app) ] && $LAUNCHER app:remove $app &>/dev/null
     done
 
     # Get Full Text Search app for nextcloud