Update wallet create docs

cmd/version.go

@@ -30,7 +30,7 @@ var versionCmd = &cobra.Command{
 
     ethdo version.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("1.4.8")
+		fmt.Println("1.4.9")
 		if viper.GetBool("verbose") {
 			buildInfo, ok := dbg.ReadBuildInfo()
 			if ok {

cmd/walletcreate.go

@@ -43,6 +43,7 @@ In quiet mode this will return 0 if the wallet is created successfully, otherwis
 		var err error
 		switch strings.ToLower(walletCreateType) {
 		case "non-deterministic", "nd":
+			assert(walletCreateSeed == "", "--seed is not allowed with non-deterministic wallets")
 			_, err = wallet.CreateWallet(walletWallet, wallet.WithType("nd"))
 		case "hierarchical deterministic", "hd":
 			assert(rootWalletPassphrase != "", "--walletpassphrase is required for hierarchical deterministic wallets")

docs/howto.md

@@ -24,6 +24,16 @@ ethdo wallet create --wallet="My wallet"
 
 Additional options are available to decide the type of wallet and encryption.
 
+## Create an HD wallet from an existing seed
+
+HD wallets can be created from an existing seed by adding the `--seed` parameter to `ethdo wallet create`, for example:
+
+```sh
+ethdo wallet create --wallet="Recreated wallet" --type=hd --seed="tooth moon mad fun romance athlete envelope next mix divert tip top symbol resemble stock family melody desk sheriff drift bargain need jaguar method"
+```
+
+The seed for an existing HD wallet can be obtained with `ethdo wallet seed`.
+
 ## Back up a wallet
 
 A wallet can be backed up with the `ethdo wallet export` command.  This creates an encrypted backup of the wallet, for example:

docs/usage.md

@@ -31,6 +31,7 @@ Spending: 0x85dfc6dcee4c9da36f6473ec02fda283d6c920c641fc8e3a76113c5c227d4aeeb100
   - `wallet`: the name of the wallet to create (defaults to "primary")
   - `type`: the type of wallet to create.  This can be either "nd" for a non-deterministic wallet, where private keys are generated randomly, or "hd" for a hierarchical deterministic wallet, where private keys are generated from a seed and path as per [ERC-2333](https://github.com/CarlBeek/EIPs/blob/bls_path/EIPS/eip-2334.md) (defaults to "nd")
   - `walletpassphrase`: the passphrase for of the wallet.  This is required for hierarchical deterministic wallets, to protect the seed
+  - `seed`: for hierarchical deterministic wallets only, use a pre-defined 24-word [BIP-39 seed phrase](https://en.bitcoin.it/wiki/Seed_phrase) to create the wallet.  **Warning** The same seed can be imported in to multiple wallets, in which case they will generate the same keys.  Please ensure that only a single wallet is active with any single seed phrase
 
 ```sh
 $ ethdo wallet create --wallet="Personal wallet" --type="hd" --walletpassphrase="my wallet secret"