NativeProcess and cmd loop

Hello,

cmd loop doesn't work correctly

file = file.resolvePath("C:\\Windows\\System32\\cmd.exe");
nativeProcessStartupInfo.executable = file;
process.addEventListener(ProgressEvent.STANDARD_OUTPUT_DATA, onOutputData); 
process.addEventListener(ProgressEvent.STANDARD_ERROR_DATA, onError);
process.addEventListener(NativeProcessExitEvent.EXIT, exitHandler);
process.start(nativeProcessStartupInfo);
process.standardInput.writeUTFBytes('for /f "TOKENS=1" %%i in (\'"wmic Process where (Name="cmd.exe") GET processid | findstr [0-9]"\') do call :concat %%i' + "\n");
process.standardInput.writeUTFBytes('goto :fin' + "\n");
process.standardInput.writeUTFBytes(':concat' + "\n");
process.standardInput.writeUTFBytes('set str=%str%,%1' + "\n");
process.standardInput.writeUTFBytes('goto :eof' + "\n");
process.standardInput.writeUTFBytes(':fin' + "\n");
process.standardInput.writeUTFBytes('@echo pid%str%' + "\n");
public function onOutputData(event:ProgressEvent):void
{ 
var stdOut:IDataInput = process.standardOutput; 
var data:String = stdOut.readUTFBytes(process.standardOutput.bytesAvailable); 
are.appendText(data+"\n");
}

the cmd echo returns "pid%str%,%1"

Thanks