Modifying an erroneous visudo file and cannot get into sudo

I recently modified the visudo file and turns out I can't get into visudo mode at all. Worst is that in Ubuntu 12.04 we can't use "su" command or log in as "root"

Here is the tips, from here

Use pkexec command,

Just type "pkexec visudo"

And modify or restore back to the original settings.

Disable auto mount from USB device

I have a problem with my Galaxy Nexus before and now my LG Nexus 4 - they keep pop up the nautilus if I insert the plug to the cable (I prefer charging my phone to the laptop).

So here is the solution, which finally I found from here


Go to your terminal, type dconf-editor. The find "org.gnome.desktop.media-handling.automount-open"

And choose your preferred choice, mine is like this:

As I prefer the phone being automounted, I just feel annoyed with the nautilus pop up, hence I untick "automount-open" but choose "automount" and "autorun-never" instead.

I feel the autorun function is so Windowish.. and wondering why it ever exists. Not that it is bad.. but for me it is less preferred.