diff --git a/scripts/change_url b/scripts/change_url
index 45029e7..ef11966 100755
--- a/scripts/change_url
+++ b/scripts/change_url
@@ -16,7 +16,7 @@ source /usr/share/yunohost/helpers
 #=================================================
 ynh_script_progression --message="Stopping a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="stop" --log_path="/var/log/$app/$app.log"
+ynh_systemd_action --service_name="$app" --action="stop" --log_path="/var/log/$app/$app.log"
 
 #=================================================
 # MODIFY URL IN NGINX CONF
diff --git a/scripts/restore b/scripts/restore
index 93e81a7..58545e4 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -26,7 +26,7 @@ ynh_restore_file --origin_path="$install_dir"
 
 chmod 750 "$install_dir"
 chmod -R o-rwx "$install_dir"
-chown -R $app: "$install_dir"
+chown -R "$app:" "$install_dir"
 
 #=================================================
 # RESTORE SYSTEM CONFIGURATIONS
diff --git a/scripts/upgrade b/scripts/upgrade
index f11b86c..3febcdd 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -16,7 +16,7 @@ source /usr/share/yunohost/helpers
 #=================================================
 ynh_script_progression --message="Stopping a systemd service..." --weight=1
 
-ynh_systemd_action --service_name=$app --action="stop"
+ynh_systemd_action --service_name="$app" --action="stop"
 
 #=================================================
 # ENSURE DOWNWARD COMPATIBILITY
@@ -44,7 +44,7 @@ fi
 # In older versions of the package, the port serving the webui was opened to anyone,
 # allowing direct access to Node-RED... let's close it.
 if yunohost firewall list | grep -q "\- $port$"; then
-    ynh_exec_warn_less yunohost firewall disallow TCP $port
+    ynh_exec_warn_less yunohost firewall disallow TCP "$port"
 fi
 
 #=================================================
@@ -117,7 +117,7 @@ yunohost service add "$app" --description="Low-code programming for event-driven
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --weight=3
 
-ynh_systemd_action --service_name=$app --action="start"
+ynh_systemd_action --service_name="$app" --action="start"
 
 #=================================================
 # END OF SCRIPT