Today I published fastcommand to PyPI.

fastcommand is a tiny Python package that wraps argparse, making it a little easier to create Python command-line utilities with multiple sub-commands. It provides a simple command decorator that can be used to annotate top-level functions. For example,

import fastcommand

@fastcommand.command("hello", help="say hello")
def command_hello(options):
    print("Hello, World!")

def main():
    cli = fastcommand.CommandParser(description="Simple fastcommand example.")
    cli.run()

Per-command options and arguments can be specified as follows:

@fastcommand.command("goodbye", help="say goodbye", arguments=[
    fastcommand.Argument("name"),
    fastcommand.Argument("--wave", "-w",
                         action="store_true", default=False)
])
def command_goodbye(options):
    print(f"Goodbye, {options.name}!")
    if options.wave:
        print("👋")

These sub-commands behave exactly as you’d expect:

$ examples/hello.py -h       
usage: hello.py [-h] [--verbose] {hello,goodbye} ...

Simple fastcommand example.

positional arguments:
  {hello,goodbye}  command
    hello          say hello
    goodbye        say goodbye

options:
  -h, --help       show this help message and exit
  --verbose, -v    show verbose output

$ examples/hello.py goodbye --help
usage: hello.py goodbye [-h] [--wave] name

positional arguments:
  name

options:
  -h, --help  show this help message and exit
  --wave, -ww

$ examples/hello.py goodbye Jason --wave
Goodbye, Jason!
👋

There are undoubtedly a myriad similar packages out there and, first-and-foremost fastcommand is a utility that helps me build the tools I’ve needed to develop over the years, but perhaps it can help you too. Please let me know if you use it and feel free to raise GitHub issues and pull-requests.

Publishing fastcommand is the first step in publishing some of the other Python utilities I’ve created over the years to help me with my software development—tools like changes which represents my own take on semantic versioning and conventional commits.