Keyboard layout identical to "US Extended" on Macbook Pro

The best thing for you is to learn the keyboards of each world ... because by using a pc keyboard on a mac or a mac keyboard on a pc you'll restrict yourself on the real use of the machine.

After a simple search those links answer to your question, you'll just have to apply it to your needs :

How to configure a keyboard on Ubuntu (simple way but may not fit your specific needs) : http://rabbitmoondot.blogspot.fr/2012/01/how-to-configure-ubuntus-keyboard-to.html https://help.ubuntu.com/community/AppleKeyboard

and the hard one (but the one that I think will answer to your need) : http://michal.kosmulski.org/computing/articles/custom-keyboard-layouts-xkb.html https://help.ubuntu.com/community/Custom%20keyboard%20layout%20definitions

Best regards.