argparse

[snippsat]

For example python test_file_name.py -t hi
Then it prints "hi"
I like the "-" as its what is used in linux a lot.

Sure but i don't use argparse,i can show you an other way with Click.
argparse is't bad it work well,just that i think Click dos a lot stuff better.

import click

@click.command()
@click.option('-t', '--string-to-echo', 'string')
def echo(string):
    click.echo(f'{string} or backwards {string[::-1]}')

if __name__ == '__main__':
    echo()

Output:
λ python hello.py -t hello
hello or backwards olleh

A look at Click i had i while ago.