No stats for aliased devices.

bindings/ruby/examples/ifconfig.rb

@@ -37,8 +37,8 @@ iflist.each do |ifname|
     " MTU:" + ifconfig.mtu.to_s +
     " Metric:" + ifconfig.metric.to_s
 
+  if (!ifname.include?(":"))
     ifstat = sigar.net_interface_stat(ifname)
-
     puts "\t" +
         "RX packets:" + ifstat.rx_packets.to_s +
         " errors:" + ifstat.rx_errors.to_s +
@@ -65,3 +65,4 @@ iflist.each do |ifname|
       "TX bytes:" + tx_bytes.to_s +
       " (" + Sigar.format_size(tx_bytes) + ")" + "\n";
   end
+end