Go Program : Identify total number of network interfaces and display the details using index

 $ vim InterfaceByIndex.go 

package main
import (
        "net"
	"fmt"
	"log"
)

func main(){
	ifaces, err := net.Interfaces()
	if err != nil {
		log.Print(fmt.Errorf("localAddresses: %v\n", err.Error()))
		return
	}
	fmt.Println("Total interfaces : ", len(ifaces))

	for ifce_num := 1; ifce_num <= len(ifaces); ifce_num++ {
		netInterface, err := net.InterfaceByIndex(ifce_num)

		if err != nil {
			fmt.Println(err)
		}
		fmt.Println("Index: ", ifce_num, "interface", netInterface)
	}
}

 $ go build InterfaceByIndex.go 

$ ./InterfaceByIndex
Total interfaces : 3
Index: 1 interface &{1 65536 lo up|loopback}
Index: 2 interface &{2 1500 eth0 00:26:b9:11:51:48 up|broadcast|multicast}
Index: 3 interface &{3 1500 wlan0 0c:60:76:61:ce:49 up|broadcast|multicast}

OR you can run the program in single commands as,

 $ go run InterfaceByIndex.go