sing.rb

require 'optparse'
require 'open3'

voice = 'bells'

ARGV.options do |opt|
  opt.on('-v VAL', '--voice=VAL') {|v| voice = v}
  opt.parse!
end

Open3.popen3 "say -v #{voice}" do |stdin, stdout, stderr|
  stdout.close
  stderr.close
  ARGV.each {|path| stdin.puts File.read path}
end