howtouse.txt

$ flask -a myapp
Usage: flask [OPTIONS] COMMAND [ARGS]...

  This shell command acts as general utility script for Flask applications.

  It loads the application configured (either through the FLASK_APP
  environment variable or the --app parameter) and then provides commands
  either provided by the application or Flask itself.

  The most useful commands are the "run" and "shell" command.

  Example usage:

    flask --app=hello --debug run

Options:
  -a, --app TEXT        The application to run
  --debug / --no-debug  Enable or disable debug mode.
  --help                Show this message and exit.

Commands:
  initdb  Initializes the database.
  run     Runs a development server.
  shell   Runs a shell in the app context.

myapp.py

import click
from flask import Flask


app = Flask(__name__)


@app.cli.command()
@click.option('--dry-run', is_flag=True)
def initdb(dry_run):
    """Initializes the database."""
    print('Initialized the database')
    if dry_run:
        print('Did not actually do anything')