This guide will show you how to install and run Linux natively on a Macbook. It's a great way to re-purpose Apples well designed hardware, and rejuvenate an old laptop. We'll be using Elementary OS, which is a fast and lightweight Linux distro. It's really straight forward to install, and is great because all the drivers work perfectly out of the box.
Step 1. First you'll need a bootable version of Mac OS X on the laptop hard drive. If you're starting with a fresh drive, you'll need to use a recovery USB installer. It's not important which version of OS X you use, since everything on the drive will be wiped.
Step 2. Download and install rEFIt [http://refit.sourceforge.net], an app that opens up more boot options for OS X. You may need to turn the system off and on again a few times for rEFIt to start working. You can test this by pressing the alt key on the keyboard when it starts up.
Step 3. Go to Elementary.io [http://elementary.io] and download the latest ISO image. When you've finished and got the OS running on your system, maybe send them a donation for their excellent work that they do for free. They accept Bitcoin too.
You also need to download the Elementary OS Installer on Github by Linus Bobcat [https://github.com/linusbobcat/create-elementary-os-installer/releases/]. This will create a USB drive which you install the OS from.
Step 4. Run the installer, and choose the Elementary ISO file. Now select the USB drive you want use and proceed.
Step 5. Turn off the laptop, and insert the new installer USB. Now turn it back on, while holding the Alt key on the keyboard and rEFIt should pop up. Select "Boot Legacy OS from HD" and press return.
Step 6. After a little while, the Elementary logo will pop up. You can now choose between the two options of "Try elementary" and "Install elementary". Select the install option.
Step 7. Follow the instructions and click "Install Now". Make sure the Erase disk and install elementary option is checked. You can also choose whether to enable full disk encryption. You'll get a warning about overwriting the internal disk, but you can press continue.
Step 8. Now select the timezone and keyboard layout for your particular Macbook.
Step 9. Input your user account details and press continue. Obviously make sure your password is a strong one unlike the example I'm using for this guide.
Step 10. Elementary will now begin installing on your system. When it has finished, click "Restart Now". You can remove the USB installer drive.
Step 11. That's it! Now when you power on, Elementary should boot up automatically. You now have a simple Linux system that runs natively on your Macbook. It gives you a solid foundation to build and tweak to your own preferences, without any of the usual hassle. Things like the touchpad, keyboard, external display drivers and everything else all work perfectly.