Cannot connect to mongodb errno:61 Connection refused

I recently installed mongodb-2.6.0 with Homebrew. After successfully installed, I tried to connect using the mongo command. I am receiving the following errors which do not allow me to connect:

Failed to connect to 127.0.0.1:27017, reason: errno:61 Connection refused

Error: couldn't connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt failed at src/mongo/shell/mongo.js:146

exception: connect failed

It can happen when the mongodb service is not running on the mac. To start it, I tried

brew services start mongodb

and it worked.

Edit: According to the discussion on this PR on homebrew: https://github.com/Homebrew/homebrew/issues/30628

brew services is deprecated, I looked around on SO and found these answers now answer the question: What is the correct way to start a mongod service on linux / OS X?

I encountered the exact same issue and here is a clear step by step process to avoid this error.

Step 1 - Installation ( Don't follow this step if you have already installed MongoDB ):

brew update
brew install mongodb

Step 2 - Run Mongo Daemon:

mkdir -p /data/db
sudo mongod

Step 3 - Run Mongo Shell Interface:

mongo

In this sequence, I was able to run the mongo command without any error. I have also detailed the error trace and its solution on this blog.