diff --git a/cluster/apt.check.update.sh b/cluster/apt.check.update.sh
index 6382eb0..3653c97 100755
--- a/cluster/apt.check.update.sh
+++ b/cluster/apt.check.update.sh
@@ -70,6 +70,12 @@ define_vars() {                                                 # {{{
 		sge_hostname="$(hostname -f)"
 	fi
 
+	## If EMPTY_ONLY_MODE wasn't defined (argument, environment variable,…)
+	if [ -z "${EMPTY_ONLY_MODE}" ]; then
+		### Set False by default
+		EMPTY_ONLY_MODE="1"
+	fi
+
 	## Script used to disable SGE queue(s)
 	sge_disable_host_queue_script="${PROGDIR}/sge.disable.host.queue.sh"
 
@@ -206,7 +212,7 @@ if [ ! "${NBARGS}" -eq "0" ]; then
 			DEBUG=0
 			;;
 		-e|--empty )                          ## Empty only mode
-			EMPTY_ONLY_MODE=0
+			EMPTY_ONLY_MODE="0"
 			;;
 		-h|--help )                           ## help
 			usage