# Creating an command line application in a markdown file.
    
    import click
We'll use the `click` library as our package for making a [`"CLI"`](# "Command Line Interface")
    
    @click.command()
    @click.argument('word')
    def main(word):
`main` is a function that take ones argument.
It is capitalized and `print`ed in the terminal

        click.echo(F"{__file__} is a program that can only print in uppercase:".upper())
        click.echo(word.upper())
        
    if __name__ == '__main__':
        if '__file__' in locals():
We are using the command line interface because python added a `__file__` attribute to the module.    
            
            main()
        else:
We are running in an interactive notebook context.