IP Lookup ... reads form a txt file a list of domains and gets their ip addresses

iplookup.go

package main

import (
	"bufio"
	"fmt"
	"net"
	"os"
)

func readDomainsFromFile(filePath string) (domains []string, err error) {

	f, err := os.Open(filePath)
	if err != nil {
		fmt.Println("File reading error", err)
		return
	}

	defer f.Close()

	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		domains = append(domains, scanner.Text())
	}
	err = scanner.Err()
	return

}

func main() {

	filePath := os.Args[1]

	domains, err := readDomainsFromFile(filePath)

	if err != nil {
		fmt.Fprintf(os.Stderr, "Error reading file %s  %v\\n", filePath, err)
	}

	for _, d := range domains {
		ips, err := net.LookupIP(d)

		if err != nil {
			fmt.Fprintf(os.Stderr, "Could not get IPs: %v\n", err)
		}

		for _, ip := range ips {
			fmt.Printf("%s. IN A %s\n", d, ip.String())
		}
	}

}