From: Mark Volkmann <r.mark.volkmann@...>
Date: 2006-02-18T04:38:09+09:00
Subject: Re: getoptlong, getopt, parseopt, which one to use for command line tool?

On 2/17/06, Charlie Bowman <cmbowma@castlebranch.com> wrote:
> There seems to be several options out there.  Which one should be used
> when creating command line tools?

I was just looking into that last night, but in my case I wanted to
stick with a standard library so the choices were GetoptLong and
OptionParser. Of those it seems to me that OptionParser is a little
better. Here's some example code that demonstrates using it. If I'm
not using it in the best way, I'm definitely open to feedback. I'm
also interested in hearing whether there is a better alternative.

# To get usage info.: ruby optionparserdemo.rb -h
# To take defaults: ruby optionparserdemo.rb
# To specify all options: ruby optionparserdemo.rb -n Mark -d 19 -c blue -f
# Example of an invalid option: ruby optionparserdemo.rb -z 42
# Example of an invalid value: ruby optionparserdemo.rb -c yellow
# Example of another invalid value: ruby optionparserdemo.rb -d foo

require 'optparse'

# Create a Hash containing option default values.
# Specified options will replace these.
options = {:name=>'unknown', :duration=>5, :color=>'red', :final=>false}

# Configure an OptionParser.
parser = OptionParser.new
parser.on('-h', '--help',
  'displays usage information') do
  puts parser
  exit
end
parser.on('-n=NAME', '--name=NAME',
  'name of person running experiment') do |v|
  options[:name] = v
end
parser.on('-d=DURATION', '--duration=DURATION', Integer,
 'duration in seconds') do |v|
  options[:duration] = v
end
parser.on('-c=COLOR', '--color=COLOR', %w(red green blue),
 'color of light') do |v|
  options[:color] = v
end
parser.on('-f', '--final', TrueClass,
  'true if final run; false otherwise') do |v|
  options[:final] = true
end

# Parse command-line options.
begin
  parser.parse($*)
rescue OptionParser::ParseError
  puts $!
  exit
end

# Output the options that will be used.
puts "Options are #{options.inspect}"

--
R. Mark Volkmann
Partner, Object Computing, Inc.