Method for realtime output of external command.

exec_command.rb

def exec_command(command, dry_run = false)
  if dry_run 
    puts command
    return 
  end

  begin
    PTY.spawn(command) do |stdin, stdout, pid|
      begin
        line = ''
        stdin.each_char { |char|
          line << char
          if line =~ /\(y\/n\): $/
            stdout.puts gets
          end
          line = '' if char == '\n'
        }
      rescue Errno::EIO
      end 
      Process.wait(pid)
    end 
  rescue PTY::ChildExited
    error_out "[Error] Cmd: #{command}"
  end
  error_out "[Error] Cmd: #{command}" unless $?.exitstatus == 0
  return true
end