My starter template for creating scripts with lots of parameters that also prompt you to fill out the missing parameters

many_parameters_fill_out_missing.rb

#!/usr/bin/env ruby

# Why not bash?
# bash is annoying for opts handling
# AND especially annoying if those opts need to be in both --key value AND --key=value format
# AND not DRY.
# and Ruby is pretty close to bash in syntax. Or it's close to Perl, which is close to Bash
# and Python feels like a bunch of boilerplate here
require 'optparse'

# WRITING YOUR OWN SCRIPT? NEED ANY ENV VARS THAT NEED DEFAULT VALUES?
# SET THEM UP HERE, LIKE SO
# ENV['DEFAULT'] = 'BAR'

# monkeypatch this because we're not using ActiveSupport
# but kinda really want to for this one thing, although I think
# in ActiveSupport it's .blank?
class NilClass
  def empty?
    true
  end
end


def or_prompt(var_name, text)
  if ENV[var_name].empty?
    print text
    ENV[var_name] = STDIN.gets.chomp
  end
  return ENV[var_name]
end


def main
  option_parser = OptionParser.new do |opts|
    opts.banner = "Usage: ADD USAGE INFORMATION HERE!!!"

    # WRITING YOUR OWN SCRIPT? GREAT, ADD PARAMETERS HERE AS YOU NEED
    # opts.on[=blah] means you can pass --graph=bar OR --graph bar and it works the same
    opts.on("--parameter[=LABEL]", "help text")   { |value| ENV["ENV_VALUE_TO_SET"] = value }

    opts.on_tail('--help', 'Display help message') do
      puts opts
      puts "\nWELCOME TO MY SCRIPT"
      exit
    end
  end

  option_parser.parse!

  # WRITING YOUR OWN SCRIPT? NOW ADD PROMPTS DOWN HERE IF YOU WANT TO ASK ABOUT UNPROVIDED PARAMETERS
  or_prompt('ENV_VALUE_TO_SET', "Please provide a value for --parameter (ie SAMPLE): ")

  # WRITING YOUR OWN SCRIPT? NOW JUST DRAW THE REST OF THE FUN OWL BELOW!
  # NOTE THAT IF YOU SET ANY ENV VARIABLES THEY WILL BE SET FOR PROCESSES SPAWNED
  # VIA IE SYSTEM
end


main