hexit.go

package main

import (
	"encoding/hex"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strings"
)

func main() {
	decodeFl := flag.Bool("d", false, "Decode Hex encoded value")
	flag.Parse()
	data := strings.Join(flag.Args(), " ")
	if data == "" {
		raw, _ := ioutil.ReadAll(os.Stdin)
		data = string(raw)
	}

	if *decodeFl {
		raw, err := hex.DecodeString(data)
		if err != nil {
			fail(err)
		}
		os.Stdout.Write(raw)
	} else {
		io.WriteString(os.Stdout, hex.EncodeToString([]byte(data)))
	}
}

func fail(err error) {
	fmt.Fprint(os.Stderr, err)
	os.Exit(1)
}