If you have closed down Terminal or Hyper and forgot to close down your mongod connection, you might get an error that says:

2018-11-04T16:17:53.473+1300 E STORAGE  [initandlisten] Failed to set up listener: SocketException: Address already in use
2018-11-04T16:17:53.474+1300 I CONTROL  [initandlisten] now exiting
2018-11-04T16:17:53.474+1300 I CONTROL  [initandlisten] shutting down with code:48

In this case, you'll have to follow these steps to manually shut down the mongod process:

1. Open up a fresh Hyper Terminal tab

2. Paste the command below into Hyper:

sudo pkill -f mongod

3. Now enter the password that you use to log on to the Mac.

4. Open a new Hyper terminal, you should now be able to run the mongod command again.