# File lib/headless/cli_util.rb, line 14
    def self.path_to(app)
      exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
      ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
        exts.each { |ext|
          exe = File.join(path, "#{app}#{ext}")
          return exe if File.executable?(exe) && !File.directory?(exe)
        }
      end
      return nil
    end