Fix a bug where oneshot services that weren't running got weird status text

check_systemd_unit

@@ -37,12 +37,13 @@ else
 			;;
 		3)
 			# In this case, the unit is not running. Whether this is an issue depends on the type of service
-			if systemctl cat backup | grep -ie '^Type=' | grep -ie 'oneshot'; then
+			if systemctl cat backup | grep -ie '^Type=' | grep -ie 'oneshot' > /dev/null 2>&1; then
 				echo "UNIT OK: $service is not running"
+				exit 0
 			else
 				echo "UNIT CRITICAL: $service is not running"
+				exit 4
 			fi
-			exit 0
 			;;
 		4)
 			echo "UNIT CRITICAL: $service is not present on this machine"