while (fgets(input, INPUT_BUFFER_SIZE, input_stream) != NULL) {
    if (batch_mode) {
        printf("%s", input);
    }

    char *cmd_argv[INPUT_ARG_MAX_NUM];
    int cmd_argc = tokenize(input, cmd_argv);

    if (cmd_argc > 0 && process_args(cmd_argc, cmd_argv, &user_list) == -1) {
        break;
    }