FLASK_APP
Linux/Mac
$ export FLASK_APP=myappWindows CMD
$ set FLASK_APP=myappFLASK_ENV
Linux/Mac
$ export FLASK_ENV=developmentWindows CMD
$ set FLASK_ENV=development
actions speak louder than words
FLASK_APP
$ export FLASK_APP=myapp$ set FLASK_APP=myappFLASK_ENV
$ export FLASK_ENV=development$ set FLASK_ENV=development