public function shellCommand()
    {
        if (!function_exists('readline_read_history')) {
            $this->outputLine('Interactive Shell is not available on this system!');
            $this->quit(1);
        }
        $subProcess = false;
        $pipes = [];

        $historyPathAndFilename = getenv('HOME') . '/.flow_' . md5(FLOW_PATH_ROOT);
        readline_read_history($historyPathAndFilename);
        readline_completion_function([$this, 'autocomplete']);

        echo "Flow Interactive Shell\n\n";

        while (true) {
            $commandLine = readline('Flow > ');
            if ($commandLine === '') {
                echo "\n";
                break;
            }

            readline_add_history($commandLine);
            readline_write_history($historyPathAndFilename);

            $request = $this->requestBuilder->build($commandLine);
            $response = new Response();
            $command = $request->getCommand();

            if ($request === false || $command->getCommandIdentifier() === false) {
                echo "Bad command\n";
                continue;
            }
            if ($this->bootstrap->isCompiletimeCommand($command->getCommandIdentifier())) {
                $this->dispatcher->dispatch($request, $response);
                $response->send();
                if (is_resource($subProcess)) {
                    $this->quitSubProcess($subProcess, $pipes);
                }
            } else {
                if (is_resource($subProcess)) {
                    $subProcessStatus = proc_get_status($subProcess);
                    if ($subProcessStatus['running'] === false) {
                        proc_close($subProcess);
                    }
                };
                if (!is_resource($subProcess)) {
                    list($subProcess, $pipes) = $this->launchSubProcess();
                    if ($subProcess === false || !is_array($pipes)) {
                        echo "Failed launching the shell sub process for executing the runtime command.\n";
                        continue;
                    }
                    $this->echoSubProcessResponse($pipes);
                }

                fwrite($pipes[0], $commandLine . "\n");
                fflush($pipes[0]);
                $this->echoSubProcessResponse($pipes);

                if ($command->isFlushingCaches()) {
                    $this->quitSubProcess($subProcess, $pipes);
                }
            }
        }

        if (is_resource($subProcess)) {
            $this->quitSubProcess($subProcess, $pipes);
        }

        echo "Bye!\n";
    }