Add host tool.

cmd/host/README

@@ -0,0 +1,5 @@
+host
+
+This is a utility to display CNAME records and IPs for a hostname. It
+was born of my frustration in trying to figure out how to get the host(1)
+tool installed on Fedora.

cmd/host/main.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net"
+)
+
+func lookupHost(host string) error {
+	cname, err := net.LookupCNAME(host)
+	if err != nil {
+		return err
+	}
+
+	if cname != host {
+		fmt.Printf("%s is a CNAME for %s\n", host, cname)
+		host = cname
+	}
+
+	addrs, err := net.LookupHost(host)
+	if err != nil {
+		return err
+	}
+
+	for _, addr := range addrs {
+		fmt.Printf("\t%s\n", addr)
+	}
+
+	return nil
+}
+
+func main() {
+	flag.Parse()
+
+	for _, arg := range flag.Args() {
+		if err := lookupHost(arg); err != nil {
+			log.Println("%s: %s", arg, err)
+		}
+	}
+}