Drop error to /dev/null

setup/so-functions

@@ -1348,7 +1348,7 @@ filter_unused_nics() {
 	
 	nic_list=()
 	for nic in "${filtered_nics[@]}"; do
-		local nic_mac=$(cat "/sys/class/net/${nic}/address")
+		local nic_mac=$(cat "/sys/class/net/${nic}/address" 2>/dev/null)
 		case $(cat "/sys/class/net/${nic}/carrier" 2>/dev/null) in
 			1)
 				nic_list+=("$nic" "$nic_mac  Link UP " "OFF")