code: func ValidatePublicKey(filePath string) error {
  	var text string
  
  	src, err := os.Stat(filePath)
  	if err != nil {
  		return errs.NewExitError("Publick key file must exist")
  	}
  
  	fMode := src.Mode()
  	if fMode.Perm() != requiredPermissions {
  		text = fmt.Sprintf("File specified has permissions %d, must have permissions %d", fMode.Perm(), requiredPermissions)
  		return errs.NewExitError(text)
  	}
  
  	fd, err := readPublicKeyFile(filePath)
  	if err != nil {
  		return errs.NewExitError("Could not read file, permissions ok")
  	}
  
  	_, err = parsePublicKeyFile(fd)
  	if err != nil {
  		return errs.NewExitError("Could not parse JSON")
  	}
  
  	return nil
  }
docs: // ValidatePublicKey checks the publickey path for valid file