func LockUser(name string) error {
	shadow, err := LookupShadow(name)
	if err != nil {
		return err
	}

	if shadow.password[0] != _LOCK_CHAR {
		shadow.password = string(_LOCK_CHAR) + shadow.password
		return edit(name, shadow)
	}
	return nil
}
func LockUser(name string) error {
	shadow, err := LookupShadow(name)
	if err != nil {
		return err
	}

	if shadow.password[0] != _LOCK_CHAR {
		shadow.password = string(_LOCK_CHAR) + shadow.password
		return edit(name, shadow)
	}
	return nil
}
// == Locking
// LockUser locks the passwd of the given user.