Showing "short usage" unless "--help" is provided

[DannyBen]

Ok, so this Clamp library is gorgeous. I love it, and it had me at "subcommand".

I am used to command line apps showing only a short "usage" pattern whenever they are executed without any argument, and only show the longer help when --help is provided.

With clamp, I see full help even without asking for it with --help.

Is there a way to change this behavior?

I am expecting to only see something like this:

$ ruby test.rb
Usage:
    test.rb [OPTIONS] SUBCOMMAND [ARG] ...

$ _

[mdub]

Thanks for the kind words.

I can kind of see what you mean. If you miss a required option or parameter, Clamp emits a short message:

$ ./examples/word 
ERROR: parameter 'WORD': no value provided

See: 'word --help'

So, it might make sense to do something similar for missing subcommands:

$ ./examples/gitdown 
ERROR: no subcommand provided

See: 'gitdown --help'

On the other hand, I played with a few popular CLI tools that have subcommands - git, docker, and kubectl - and note that all of them show exactly the same behaviour for CMD and CMD --help.

So, I'm a bit torn about whether to change Clamp's default behaviour.

Meanwhile, you could use this trick:

Clamp do

  # ...

  self.default_subcommand = "barf"

  def subcommand_missing(name)
    signal_usage_error "no subcommand specified" if name == "barf"
    super
  end

end

[DannyBen]

I see your point. I never actually made the distinction between CLI with subcommands, and without.

[mdub]

I'm still torn on this one. I'm tempted to change the default behaviour as suggested, ie.

$ ./examples/gitdown 
ERROR: no subcommand provided

See: 'gitdown --help'

[mdub]

I'm going to default to the devil we know, i.e. not changing current behaviour.