-system("/usr/local/bin/extrahdctrl scanhd ide");
-system("/usr/local/bin/extrahdctrl scanhd partitions");
+
+#workaround to suppress a warning when a variable is used only once
+my @dummy = ( ${Header::colourgreen}, ${Header::colourred} );
+undef (@dummy);
+
+system("/usr/local/bin/extrahdctrl scanhd ide >/dev/null");
+system("/usr/local/bin/extrahdctrl scanhd partitions >/dev/null");