CLI Exit Codes
Reference: Exit Codes for test runner.
Exit codes indicate some level of information and the cli is designed to exit if it cannot complete it's tasks successfully. This is usually useful for indicating tests failed if you're using the cli for Continuous Integration, and want deploys to stop incase there are regressions not approved.
Here's a reference of the exit codes.
|50||Tests failed and there is a possible regression.|
|51||Unable to authenticate or start working. Usually a configuration error.|