All 15 Command-Line Interfaces (argparse) questions
More in Command-Line Interfaces (argparse)
What is the difference between a positional argument and an optional argument (flag) in argparse? How do you specify a default value and a type conversion for an argument? How do you restrict an argument's accepted values using the 'choices' parameter? How do you accept a variable number of arguments for a single flag, like a list of filenames? How do you implement boolean flags using action='store_true' and action='store_false'? How do you provide a short and a long form for the same flag, like -v and --verbose? How do you implement subcommands (like 'git commit' or 'git push') using argparse's add_subparsers()? How do you group related arguments visually in the generated --help output using argument groups? How do you implement mutually exclusive arguments, where the user must choose EXACTLY ONE of a set of flags? How do you write a custom 'type=' validation function for argparse that raises a properly-formatted error for invalid input?
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Python › Command-Line Interfaces (argparse)

How do you create a basic command-line argument parser using argparse?

Beginner

Answer

Instantiate argparse.ArgumentParser(), call add_argument() for each expected argument, then call parse_args() to parse sys.argv and return a Namespace object with the parsed values as attributes.
import argparse

parser = argparse.ArgumentParser(description="Greet a user")
parser.add_argument("name", help="Name of the person to greet")
args = parser.parse_args()
print(f"Hello, {args.name}!")
# python greet.py Sam  -> "Hello, Sam!"
Real-world example Building a simple CLI script that greets a user by name, passed as a positional command-line argument.

Common follow-ups: What happens automatically if the user runs the script without providing the required 'name' argument?

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All 15 Command-Line Interfaces (argparse) questions