Inbox CLI 
A friendly command line interface to gmail.
I use it to keep track of incoming notifications from github and trello in a keyboard-shortcut, developer friendly manner.
Installing
$ npm install --global inbox-cli
$ inbox-cli
The first time you run inbox-cli, it will use OAuth to authenticate, which means you'll have to open a link in your web browser, login to google, and paste and access code into the application.
Now you're ready to go!
Usage
Hit ? in the main view and open help to see the list of keyboard shortcuts!
Supported platforms
MacOS only for now, since it depends on being able to shell out to open.