Posted by (author unknown) at MacOSXHints.com
It seems like Apple disabled the “Press Backspace to go back a page” feature in Safari 6 due to users having complained about losing text entered in text fields when they accidentally pressed the backspace key. If you liked this feature, you can enable it again using this command:
defaults write com.apple.Safari NSUserKeyEquivalents -dict-add Back "\U232b"
If you ever want to disable it, there are two possibilities. The first, if you don’t have any other shortcuts for Safari, is to run this command:
defaults delete com.apple.Safari NSUserKeyEquivalents
It will delete all Safari keyboard shortcuts.
The second method is a bit more time-consuming. You need to first create a keyboard shortcut for Safari, for the “Back” command, in the preferences. Then, if you apply the first command above, you’ll be able to delete it. If you don’t have a shortcut set up for the Back command before running the first command above, it won’t display in the Keyboar …