I've installed Ubuntu 13.10 on a Lenovo yoga 13. In order to make the backlight work with the keys I've been following some instructions of this answer (link edited)
The process I followed was this:
1) sudo gedit /etc/default/grub (generates errors, I think they are irrelevant - have checked in vim the edit worked)
2) sudo update-grub
3) blacklisted the ideapad_laptop by adding "blacklist ideapad_laptop" to /etc/modprobe.d/blacklist.conf file
Step 2) generates error: /usr/sbin/grub-mkconfig: 27: /etc/default/grub: want: not found
Answers from the comments
cat /etc/default/grub does show contents of the file
fgrep want /etc/default/grub gives: # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
sudo cat /etc/default/grub also shows contents of the file
Update
The grub error from step 2 occurs whenever I try to install anything. I have previously tried to run the command sudo apt-get install grub-pc - which also generates this error. I'm worried I've upset the balance of my computer's universe...
fgrep want /etc/default/grub
to your question.