I screwed with some bin files in MAC OSX, and can't log in. Anyways, I want a bootable ubuntu usb so I can recover my files/look at the disks. I KNOW HOW TO MAKE A USB BOOTABLE IN MAC. However, I do not know how to make one in Ubuntu. I have a computer with ubuntu, but need to make a bootable usb FOR A MAC. Any help is greatly appreciated.
You will of course need a OS X Installer Image. To get this you can follow the instructions here
After you have got your installer media, you can use ubunut's built-in utility
Startup Disk Creator to make a bootable USB. SO, open dash and search for
Startup Disk Creator and open it. Follow the on-screen instructions or refer to this document from ubuntu.
Don't even think about using Ubuntu to fix OS X. Use the recovery partition which should be part of any modern installation of OS X, by booting and pressing CMD-R. You can then repair as needed - perhaps even install a fresh OS X on top of your existing installation which can fix most broken things.
See https://support.apple.com/en-us/HT201314 for details.
If everything goes completely wrong, restore from a Time Machine backup.