If you would like more control over how your tests are run - for example, you'd like to use a different test framework, don't want to use the Protractor command line tool, or have very special setup - you can use only the Protractor library. Include with
var protractor = require('protractor');
After setting up a webdriver instance, you can create an instance of Protractor with
var protractorInstance = protractor.wrapDriver(driver);