           
           # set written data
           write_body = ""
-          write_body += result.stdout  if flags.stdout
-          write_body += result.stderr  if flags.stderr
+          write_body += result.stdout if flags.stdout
+          write_body += result.stderr if flags.stderr
           
           # check to exist the file if flags.overwrite equals false
-          throw new Error("E003: File is found (" + filename + ")")  if fs.existsSync(filename)  unless flags.overwrite
+          throw new Error("E003: File is found (#{filename})") if fs.existsSync(filename)  unless flags.overwrite
           fs.writeFileSync filename, write_body
         else
-          grunt.log.writeln command.command + " > " + filename + ": NG"
+          grunt.log.writeln "#{command.command} > #{filename}: NG"
         callback res
 
 

    # run command each file
    # 
    functions = _(files).map((filename) ->
      exec_command.bind this, filename
    )

    grunt.log.writeln "Processing tasks..."

      _(commands).extend obj
      commands
    , {})

  
  # to boolean
