Overriding command-line --help 'usage' section

[justfalter]

Right now, '--help' outputs a rather generic 'usage' line:

usage: foo.rb [...--param=val...]

The only thing that changes is the script file name.

I'm writing a script that accepts one of several commands ('list', 'run', 'help') before handing things over to configliere for parsing.

Unfortunately, I can't seem to cleanly override the usage output such that:

$ foo.rb
usage: foo.rb [command]

Commands:
   run  - run some stuff
   list   - list stuff to run
   help - get some help

$ foo.rb run --help
usage: foo.rb run [...--param=val...]

Params:
     bla bla bla

$ foo.rb list --help
usage: foo.rb list [...--param=val...]

Params:
     bla bla bla

It's trivial to parse the 'command' from ARGV (just an ARGV.shift) and then directing things to the appropriate instance of Configliere::Param.

Looking at Configliere::Commandline, it appears that there might have been some intent to support overriding the parsers 'usage', as there is an an 'attr_writer :usage'.

The only way I've managed to override the usage was by doing something like:

    params = Configliere::Param.new
    params.use(:commandline)
    my_usage_mod = Module.new do
      def usage
         "usage: #{raw_script_name} run [...-param=val...]"
      end
    end
    params.extend  my_usage_mod

I've no problem tweaking things and sending a pull request. I just wanted to make sure I wasn't missing something, first.