Allow me to fan the flames. I find for simple scripts, docopt[0] is more than enough. It looks like the click's docs has a discussion of the differences.

[0] http://docopt.org/

I don't know man. Have used docopt, but click just feels right to me.

I never have to think about the "CLI" when using click, everything "just works"...

http://click.pocoo.org/5/why/#why-not-docopt-etc

Thank you for this! Wow! Just Wow!

Click makes python attractive for CLI's. It is far better than bash and perl for simple stuff. Fire looks useful for hacks but Click has been excellently intuitive for me.

Perl6 has nice builtin cli construction from method definitions and doc comments

    cat > cli.pl6

    #| Duplicates without frobnication
    multi sub MAIN( 'duplicate', Int $times, Str $text ) {
      say $text x $times;
    }
    
    #| Frobnicates up to a limit
    multi sub MAIN('frobnicate', Int :$length = 24, Bool :v(:$verbose))
    {
        say 'Verbosity ', ($verbose ?? 'on' !! 'off');
    }


    perl6 cli.pl
    Usage:
      cli.pl6 duplicate <times> <text> -- Duplicates without frobnication
      cli.pl6 [--length=<Int>] [-v|--verbose] frobnicate -- Frobnicates up to a limit


    perl6 cli.pl6 duplicate 3 blah...
    blah...blah...blah...

The builtin argparse module is also really easy to use for simple stuff.

It's ok but for some scripts it ends up being half of the code and you end up with a script that's dealing with an opaque args object.

Here's a decent example of this https://github.com/pytorch/examples/blob/master/imagenet/mai...

Could you solve ghat with click much easier? This seems mostly related to various flags set up, which would need to exist in the code anyway.

I'm saying that this should really be a function like

    def train(
      data: File,
      arch='resnet18',
      workers=4,
      epochs=90,
      start_epoch=0,
      batch_size=256,
      learning_rate=0.9,
      momentum=1e-4,
  ):
    ...

that could be exposed as a cli if __name__ is main but otherwise can be imported in a notebook or another script.

Fire is an interesting project that's great for testing and hacking. But for crafting Python CLIs from scratch, I fail to understand why Argh[0] doesn't receive more attention.

My only frustrations are a missing default handler for --version, and that I can't use argument names colliding with builtins such as 'input'. All the flexibility of argparse without boilerplate.

[0] https://github.com/neithere/argh