Referring to this question: Restore MacBook Pro to factory settings without disc, I find it rather reckless to post an answer to an OP that obviously does not know what the effects will be.
Should such an answer be flagged or deleted, even with a warning? I'd say yes.
Included copy below in case of answer deletion.
Restore MacBook Pro to factory settings without disc Is there a way of restoring a MacBook Pro to it's factory settings without a disc? I want all files deleted and it to basically be like I just received it from Apple.
I know you can do it with Dell machines - surely you can with Apple machines?
A I'm referring to:
WARNING, the below command will erase every file in your drive root.
This includes system files, personal files and application files and can not be reversed. That being said,
sudo rm -rf /
Closest you're going to get without a disk.