code: function prepareArgsForReboot() {
      const deferred = q.defer();
      let startupScripts;
      let startupCommands;
      let startupCommandsChanged;
  
      const STARTUP_DIR = '/config/';
      const STARTUP_FILE = `${STARTUP_DIR}startup`;
      const REBOOT_SIGNAL = ipc.signalBasePath + signals.REBOOT;
  
      if (!fs.existsSync(STARTUP_DIR)) {
          logger.debug('No /config directory. Skipping.');
          deferred.resolve();
          return deferred.promise;
      }
  
      try {
          startupCommands = fs.readFileSync(STARTUP_FILE, 'utf8');
      } catch (err) {
          logger.warn('Error reading starup file.');
          deferred.reject(err);
          return deferred.promise;
      }
  
      try {
          startupScripts = fs.readdirSync(REBOOT_SCRIPTS_DIR);
      } catch (err) {
          logger.warn('Error reading directory with reboot args.');
          deferred.reject(err);
          return deferred.promise;
      }
  
      // Make sure there's a new line at the end in case we add anything
      startupCommands += EOL;
  
      // If we just rebooted, make sure the REBOOT signal file is deleted
      // so scripts don't think we need to reboot again
      if (startupCommands.indexOf(REBOOT_SIGNAL) === -1) {
          startupCommandsChanged = true;
          startupCommands += `rm -f ${REBOOT_SIGNAL}${EOL}`;
      }
  
      startupScripts.forEach((script) => {
          const fullPath = REBOOT_SCRIPTS_DIR + script;
          if (startupCommands.indexOf(fullPath) === -1) {
              startupCommandsChanged = true;
              startupCommands += `if [ -f ${fullPath} ]; then${EOL}`;
              startupCommands += `    ${fullPath} &${EOL}`;
              startupCommands += `fi${EOL}`;
              startupCommands += EOL;
          }
      });
  
      if (startupCommandsChanged) {
          try {
              fs.writeFileSync(STARTUP_FILE, startupCommands);
          } catch (err) {
              logger.warn('Failed writing startup file', STARTUP_FILE, err);
          }
      }
  
      deferred.resolve();
  
      return deferred.promise;
  }
docs: Copies all the saved arguments (from saveArgs) to the startup file
  so that when the box reboots, the arguments are executed.