--- /etc/init.d/samba-ad-dc.orig	2017-02-17 02:47:47.546857284 +0100
+++ /etc/init.d/samba-ad-dc	2017-02-17 02:58:40.130864129 +0100
@@ -32,7 +32,17 @@ case "$1" in
 			. "/usr/share/univention-config-registry/init-autostart.lib"
 			check_autostart samba-ad-dc samba4/autostart
 		fi
-		SERVER_ROLE=`samba-tool testparm --parameter-name="server role"  2>/dev/null | tail -1`
+		testparm_output=$(samba-tool testparm --parameter-name="server role" 2>/dev/null)
+		rc=$?
+		if [ $rc != 0 ]; then
+			log_failure_msg "samba-tool testparm"
+			exit 1
+		fi
+		if [ -z != "$testparm_output" ]; then
+			log_failure_msg 'samba-tool testparm --parameter-name="server role"'
+			exit 1
+		fi
+		SERVER_ROLE=$(echo "$testparm_output" | tail -1)
 		if [ "$SERVER_ROLE" != "active directory domain controller" ]; then
             	    echo "Samba is not configured as AD DC."
 		    exit 0