sudo chmod -R 777 /

 sudo chmod -R 777 /

I did this. It was a mistake. Is there any way to undo it?

Basically it's messed up more things than I can list. I don't have time-machine enabled on my mac.

Solution 1:

Take a look at Apple's Disk Utility's Repair Disk Permissions feature:

http://support.apple.com/kb/HT1452?viewlocale=en_US

Solution 2:

From http://support.apple.com/kb/HT2963:

Using the Repair Privileges Utility

Most users of Mac OS X have not intentionally modified privileges and simply need a utility to reset system privileges to their correct default values. If you have Mac OS X 10.2 and later, this utility is included in the operating system. If you have Mac OS X 10.1 you can download it. For versions 10.0 to 10.1.4, you must update to version 10.1.5 first.

For Mac OS X 10.2 or later, open Disk Utility (/Applications/Utilities/). Select your Mac OS X startup volume in the column on the left of the Disk Utility window, then click the First Aid tab. Click the Repair Disk Permissions button. You may see an erroneous message.

Solution 3:

You're in luck:

• About Disk Utility's Repair Disk Permissions feature

It won't fix everything, but it will fix everything that's listed in the bill of materials file for an installed package.