Skip empty group on login check

bin/check_last_login.sh

@@ -111,6 +111,10 @@ for ssh_group in "${ssh_groups[@]}"; do
 		fi;
 	fi;
 	while read -r username; do
+		# skip empty, if group exists but has no users
+		if [ "${username}" = "" ]; then
+			continue;
+		fi;
 		# check that user exists in passwd
 		if ! id "${username}" &>/dev/null; then
 			out_string="[!] User $username does not exists in /etc/passwd file";