Flask: Run Hello World Environment variables

Alternativelly we can set the environment variable FLASK_APP to the name of the file without the extension.

We can also set the FLASK_DEBUG environment variable to 1 tuning on the debug-mode.

Then we execute flask run.

It is a bit different how you do this on Linux or Mac vs. on MS Windows.

In either case once Flask is running, you can use your browser to visit your new web application on the http://127.0.0.1:5000/ address or the http://localhost:5000/ address which is the same. You can also use curl on the command line to see the content of the web page.

Once you had enough enjoying the view of your new application, you can hit Ctr-C to stop the program.

Linux/Mac:

$ FLASK_APP=hello FLASK_DEBUG=1 flask run

or

$ export FLASK_APP=hello
$ export FLASK_DEBUG=1
$ flask run

Then visit: http://127.0.0.1:5000/ or type in

curl http://localhost:5000/

MS Windows

On the command line or in the terminal of PyCharm, VS Code or any other IDE:

set FLASK_APP=hello
set FLASK_DEBUG=1
flask run