Problem:

After I install MongoDB, I ran

mongod

in my terminal.

Then it ended up here, like forever...

2017-11-05T18:59:14.589+0800 I NETWORK [thread1] waiting for connections on port 270

Solution:

Open a new terminal and enter:

cd /usr/local/bin

./mongod

Why?

The waiting for connection message in the terminal is a sign indicating that mongodb is running successfully.

We just leave it and open a new terminal for connection.