Add initial CLI

.gitignore

@@ -0,0 +1,4 @@
+.DS_Store
+dist
+build
+node_modules

README.md

@@ -108,6 +108,19 @@ func main() {
 }
 ```
 
+## CLI
+
+```bash
+go get -u github.com/miguelmota/go-ethereum/cmd/geth-hdwallet
+```
+
+```bash
+$ geth-hdwallet -mnemonic "tag volcano eight thank tide danger coast health above argue embrace heavy" -path "m/44'/60'/0'/0/0"
+
+public address: 0xC49926C4124cEe1cbA0Ea94Ea31a6c12318df947
+private key: 63e21d10fd50155dbba0e7d3f7431a400b84b4c2ac1ee38872f82448fe3ecfb9
+```
+
 ## Test
 
 ```bash

cmd/geth-hdwallet/main.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+
+	hdwallet "github.com/miguelmota/go-ethereum-hdwallet"
+)
+
+func main() {
+	var mnemonic string
+	var hdpath string
+
+	flag.StringVar(&mnemonic, "mnemonic", "", "Mnemonic")
+	flag.StringVar(&hdpath, "path", "", "HD path")
+	flag.Parse()
+
+	wallet, err := hdwallet.NewFromMnemonic(mnemonic)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	path := hdwallet.MustParseDerivationPath(hdpath)
+	account, err := wallet.Derive(path, false)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	privateKey, err := wallet.PrivateKeyHex(account)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println("public address:", account.Address.Hex())
+	fmt.Println("private key:", privateKey)
+}