config: add password sub command for setting obscured passwords

cmd/config/config.go

@@ -16,6 +16,7 @@ func init() {
 	configCommand.AddCommand(configCreateCommand)
 	configCommand.AddCommand(configUpdateCommand)
 	configCommand.AddCommand(configDeleteCommand)
+	configCommand.AddCommand(configPasswordCommand)
 }
 
 var configCommand = &cobra.Command{
@@ -121,3 +122,20 @@ var configDeleteCommand = &cobra.Command{
 		fs.DeleteRemote(args[0])
 	},
 }
+
+var configPasswordCommand = &cobra.Command{
+	Use:   "password <name> [<key> <value>]+",
+	Short: `Update password in an existing remote.`,
+	Long: `
+Update an existing remote's password. The password
+should be passed in in pairs of <key> <value>.
+
+For example to set password of a remote of name myremote you would do:
+
+    rclone config password myremote fieldname mypassword
+`,
+	RunE: func(command *cobra.Command, args []string) error {
+		cmd.CheckArgs(3, 256, command, args)
+		return fs.PasswordRemote(args[0], args[1:])
+	},
+}

fs/config.go

@@ -1034,6 +1034,24 @@ func CreateRemote(name string, provider string, keyValues []string) error {
 	return UpdateRemote(name, keyValues)
 }
 
+// PasswordRemote adds the keyValues passed in to the remote of name.
+// keyValues should be key, value pairs.
+func PasswordRemote(name string, keyValues []string) error {
+	if len(keyValues) != 2 {
+		return errors.New("found key without value")
+	}
+	// Suppress Confirm
+	Config.AutoConfirm = true
+	passwd := MustObscure(keyValues[1])
+	if passwd != "" {
+		configData.SetValue(name, keyValues[0], passwd)
+		RemoteConfig(name)
+		ShowRemote(name)
+		SaveConfig()
+	}
+	return nil
+}
+
 // JSONListProviders prints all the providers and options in JSON format
 func JSONListProviders() error {
 	b, err := json.MarshalIndent(fsRegistry, "", "    ")