Version 1.2: Add error handling

Main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"os"
 )
 
 func main() {
@@ -10,20 +11,29 @@ func main() {
 
 	var input string
 	var wantPrefixes bool
-	localIPAddress := getLocalIP()
-	flag.StringVar(&input, "i", localIPAddress, "Specify IP address or domain name.")
+
+	flag.StringVar(&input, "i", "", "Specify IP address or domain name.")
 	flag.BoolVar(&wantPrefixes, "p", false, "Enable printing of advertised BGP prefixes.")
 	flag.Parse()
-	var isIPCorrect bool = checkIPSyntax(input)
-	if isIPCorrect == true {
-		printIPInfo(input, wantPrefixes)
+
+	if input == "" {
+		fmt.Println("FATAL: No IP address or domain name was specified.")
+		os.Exit(1)
 	} else {
-		ipaddress := resolveDNSHostname(input)
-		if checkIPSyntax(ipaddress) == true {
-			fmt.Println("Domain Name:	", input)
-			printIPInfo(ipaddress, wantPrefixes)
+		if input == "me" {
+			input = getLocalIP()
+		}
+		var isIPCorrect bool = checkIPSyntax(input)
+		if isIPCorrect == true {
+			printIPInfo(input, wantPrefixes)
 		} else {
-			fmt.Println("Invalid query.")
+			ipaddress := resolveDNSHostname(input)
+			if checkIPSyntax(ipaddress) == true {
+				fmt.Println("Domain Name:	", input)
+				printIPInfo(ipaddress, wantPrefixes)
+			} else {
+				fmt.Println("Invalid query.")
+			}
 		}
 	}