PCF - Cloud Foundry Overview - Starting, Restarting and Restaging applications

do you know the difference between restarting, restaging and redeploying an application?
How does each of these affect the services, environment-variables available to an application?

Starting an app: 
1. '$ cf push YOUR-APP' command with manifest entry of command attribute i.e. command: node YOUR-APP.js
2. '$ cf push YOUR-APP -c "node YOUR_APP.js"', where -c command line option for defining the start command.

First time deployment using 'cf push' uses buildpack start command by default.

Restarting an app:
Restarting your application stops your application and restarts it with the already compiled droplet. Diego cell unpacks, compiles and runs a droplet on a container.

'cf restart YOUR-APP'

Restaging an app:
Restaging your application stops your application and re-stages it, by compiling a new droplet and starting it.

'cf restage YOUR-APP'