import typer

app = typer.Typer()


@app.command()
def hello():
    print(f"Hello World")


if __name__ == "__main__":
    app()

# DO NOT DO THIS: Not extensible. Use Typer() instead.
import typer


def main():
    print(f"Hello World")


if __name__ == "__main__":
    typer.run(main)

python main.py

python main.py hello

python main.py --help

from typing import Annotated

import typer

app = typer.Typer()


@app.command()
def hello(name: Annotated[str, typer.Argument()] = "World"):
    # Note that name is an optional Argument, as a default is provided
    print(f"Hello {name}")


if __name__ == "__main__":
    app()

python main.py
python main.py Rick

# DO NOT DO THIS: old style. Use Annotated instead.


@app.command()
def main(name: str = typer.Argument(default="World")):
    # Note that name is an optional Argument, as a default is provided
    print(f"Hello {name}")

# DO NOT DO THIS: old style. Use Annotated without a default value instead.


@app.command()
def main(name: str = typer.Argument(default=...)):
    # Note that name is now a required Argument
    print(f"Hello {name}")

from typing import Annotated

import typer

app = typer.Typer()


@app.command()
def main(user_name: Annotated[str, typer.Option()]):
    # On the CLI, the required user name can be specified with --user-name
    print(f"Hello {user_name}")


if __name__ == "__main__":
    app()

from typing import Annotated

import typer

app = typer.Typer()


@app.command()
def main(user_name: Annotated[str, typer.Option("--name", "-n")]):
    # On the CLI, the required user name can be specified with -n or --name
    print(f"Hello {user_name}")


if __name__ == "__main__":
    app()

python main.py -n "Rick"
python main.py --name "Morty"

from typing import Annotated

import typer

app = typer.Typer()


@app.command()
def main(user: Annotated[list[str] | None, typer.Option()] = None):
    if not user:
        print(f"No users provided!")
        raise typer.Abort()
    for u in user:
        print(f"Processing user: {u}")


if __name__ == "__main__":
    app()

python main.py --user Rick --user Morty --user Summer

from rich import print

print("[bold red]Alert![/bold red] [green]Portal gun[/green] shooting! :boom:")

from typing import Annotated

import typer

app = typer.Typer(rich_markup_mode="rich")


@app.command()
def create(
    username: Annotated[
        str, typer.Argument(help="The username to be [green]created[/green]")
    ],
):
    """
    [bold green]Create[/bold green] a new [italic]shiny[/italic] user. :sparkles:

    This requires a [underline]username[/underline].
    """
    print(f"Creating user: {username}")


@app.command(help="[bold red]Delete[/bold red] a user with [italic]username[/italic].")
def delete(
    username: Annotated[
        str, typer.Argument(help="The username to be [red]deleted[/red]")
    ],
):
    """
    Some internal utility function to delete.
    """
    print(f"Deleting user: {username}")


if __name__ == "__main__":
    app()

from typing import Annotated

import typer

app = typer.Typer(rich_markup_mode="markdown")


@app.command(help="**Delete** a user with *username*.")
def delete(
    username: Annotated[
        str, typer.Argument(help="The username to be **deleted** :boom:")
    ],
):
    print(f"Deleting user: {username}")


if __name__ == "__main__":
    app()