private Set<String> complete(final String cmd) {
		final Set<String> set = new HashSet<>();
		for (final String s : commandMap.keySet()) {
			if (s.startsWith(cmd)) {
				set.add(s);
			}
		}
		for (final String s : helpCommands.keySet()) {
			if (s == null) {
				if ("help".startsWith(cmd)) {
					set.add("help");
				}
			} else if (s.startsWith(cmd)) {
				set.add(s);
			}
		}
		return set;
	}