Hi! Crunched for time, but you can take a look at the help message for the build command:
exp build:android --help Mon Aug 28 20:42:13 2017
Usage: build:android|ba [options] [project-dir]
Build a standalone APK for your project, signed and ready for submission to the Google Play Store.
Options:
-c, --clear-credentials Clear stored credentials.
--non-interactive Fails if an interactive prompt would be required to continue.
-h, --help output usage information