Reinstall MacOS on a Macbook that doesn't have MacOS anymore? I'm new to this site, so pardon me if I do or say something wrong.

I have an old MacBook late 2008 unibody that has Linux installed on it (3 different linuxes, don't ask why). I bought this MacBook second hand a while ago. I wanted to install Linux on my Mac but didn't know what I was doing back then, and accidentally deleted the whole MacOS and everything. Currently, I'm tripple booting my "Linuxes" via "rEFInd". I want to install the latest MacOS available for my model but I don't know how to do it. Where would I find a DMG and how would I install it. Could anyone guide me or help me? I don't have any warranty nor do I have an Apple store where I live.

Thanks,
You can obtain the latest Build of El Capitan (10.11.x) directly from Apple via this link.



As for creating a bootable USB installer, I would recommend converting the dmg to an iso via AcetoneISO.

It'll convert the DMG to an ISO for you. After that, create the bootable USB  with your new yourmacos.iso using DD.

dd if=/path/to/yourmacos.iso of=/dev/sdX &amp;&amp; sync


I don't know if you are familiar with this but dd does byte by byte copying and 
sync ensures that all data has been written to your USB (so you can savely unplug/eject it afterwards).