homebrew-cask-versions/lib/cask/system_command.rb

class Cask::SystemCommand
  def self.run(command, options={})
    command = _process_options(command, options)
    output = ''
    IO.popen(command, 'r+') do |pipe|
      if options[:input]
        options[:input].each { |line| pipe.puts line }
      end
      pipe.close_write
      while line = pipe.gets
        output << line
        ohai line.chomp if options[:print]
      end
    end
    if options[:plist]
      Plist::parse_xml(output)
    else
      output
    end
  end

  def self._process_options(command, options)
    if options[:sudo]
      command = "sudo #{_quote(command)}"
    end
    if options[:args]
      command = "#{command} #{options[:args].map { |arg| _quote(arg) }.join(' ')}"
    end
    case options[:stderr]
    when :silence then
      command = "#{command} 2>/dev/null"
    when :merge, nil then
      command = "#{command} 2>&1"
    end
    command
  end

  def self._quote(string)
    %Q('#{string}')
  end
end