It would be nice if the debug console had a little help page of itself, to describe the syntax to issue commands (also the nested ones), and a disclaimer that usage can be dangerous.

Maybe add a debug-console-only command like help that shows how to use nested commands and potentially other advanced tricks, and add 'for more information on using this console type XXX'.

See also:
- https://github.com/bitcoin/bitcoin/pull/7783#issuecomment-248274853
- https://github.com/bitcoin/bitcoin/issues/8544#issuecomment-240970925
- #8912 Console command paths cannot be specified correctly with backslashes
{
    QString cmd = ui->lineEdit->text();
    if(!cmd.isEmpty())
    {
        std::string strFilteredCmd;
        try {
            std::string dummy;
            if (!RPCParseCommandLine(dummy, cmd.toStdString(), false, &strFilteredCmd)) {
                // F
                throw std::runtime_error("Invalid command line");
            }
        } catch (const std::exception& e) {
            QMessageBox::critical(this, "Error", QString("Error: ") + QString::fromStdString(e.what()));
            return;
        }
        ui->lineEdit->clear();
        cmdBeforeBrowsing = QString();
        message(CMD_REQUEST, QString::fromStdString(strFilteredCmd));
        Q_EMIT cmdRequest(cmd);
        cmd = QString::fromStdString(strFilteredCmd);
        // R
        history.removeOne(cmd);
        // A