Changed hostname, closed before changing hosts, now sudo is broken, catch-22!

[begtognen]

I'm using Lubuntu 12.04.
I was trying to change my computer name to "main" and I messed up, I'm not sure what to do now.
I was following the directions on this page.
Here's what I did:

sudo leafpad /etc/hostname

I changed the name, then stupidly closed the file, before changing "/etc/hosts"
Now when I try to move on to the next step (sudo leafpad /etc/hosts), or try any command that begins with "sudo" I get this error:

sudo: unable to resolve host main
No protocol specified
No protocol specified

I can see that the problem is that I've changed the hostname, so the computer's bewildered by my efforts to use sudo because now hostname and hosts don't match. All I need to do is change the name in hosts, but of course I can't do that without sudo.

Any ideas?

And if there isn't a way to fix it, reinstalling Lubuntu 12.04 will work, yes?

[steeldriver]

You should be able to fix it from the recovery console, you will need to remount the filesystem with rw permissions and then use a commandline editor e.g. after dropping to the root shell,

# mount -o remount,rw /
# nano /etc/hosts

and make your changes... Ctrl-o to save and Ctrl-x to quit

--> http://www.psychocats.net/ubuntu/fixsudo

[begtognen]

Thank you so much! This worked a treat.