For poster on JRuby forum to find JRuby in his Windows path

find_jruby.rb

def list_candidates(extensions, command_name)

  dirs = ENV['PATH'].split(File::PATH_SEPARATOR)
  filespecs = []
  dirs.each do |dir|
    filespec_stem = File.join(dir, command_name)
    extensions.each do |extension|
      filespecs << (filespec_stem + extension)
    end
  end
  filespecs
end

# filespecs = list_candidates([''], 'ruby')  # for my testing on a Mac
filespecs = list_candidates(%w(.bat .exe), 'jruby')

found_filespecs, not_found_filespecs = filespecs.partition { |spec| File.exist?(spec) }

puts "\n\nNot Found:\n\n#{not_found_filespecs.join("\n")}"
puts "\n\nFound:\n\n#{found_filespecs.join("\n")}"