code: func main() {
  	sess := session.Must(session.NewSession())
  
  	nameFilter := os.Args[1]
  	awsRegion := "us-east-1"
  	svc := ec2.New(sess, &aws.Config{Region: aws.String(awsRegion)})
  	fmt.Printf("listing instances with tag %v in: %v\n", nameFilter, awsRegion)
  	params := &ec2.DescribeInstancesInput{
  		Filters: []*ec2.Filter{
  			{
  				Name: aws.String("tag:Name"),
  				Values: []*string{
  					aws.String(strings.Join([]string{"*", nameFilter, "*"}, "")),
  				},
  			},
  		},
  	}
  	resp, err := svc.DescribeInstances(params)
  	if err != nil {
  		fmt.Println("there was an error listing instances in", awsRegion, err.Error())
  		log.Fatal(err.Error())
  	}
  	fmt.Printf("%+v\n", *resp)
  }
docs: // This example will list instances with a filter
  //
  // Usage:
  // filter_ec2_by_tag <name_filter>