Doch doch ...

Also :

echo Alarm für FF XYZ >> C:\Logfiles\SMS-Log-NEU.TXT
type C:\Logfiles\SMS-Log.TXT >> C:\Logfiles\SMS-Log-NEU.TXT
del C:\Logfiles\SMS-Log.TXT
ren C:\Logfiles\SMS-Log-NEU.TXT C:\Logfiles\SMS-Log.TXT

Geht .. gerade getestet .....

Gruß Joachim