Hello Sorry if it's simple, it's y first post. This is to bullet proof a Macbook air for an exam. Mac will be clean installed with only libreoffice, output will be USB key (another Mac in the bag as backup) I am looking to copy the created file to the usb key every 5 minutes as a backup in case of system failure crash/death. So that only action is to unplug USB and stick it into the other Mac out of the bag. For the moment I am thinking cp script and crontab Any better idea ? someone must have done it before me.