I "tried" to set the default brightness for Ubuntu 14.04. Following here, At first I did:

Code:
echo 5 > /sys/class/backlight/acpi_video0/brightness
then:
Code:
sudo apt-get install xbacklight
then copy-pasted below inside the terminal:
Code:
sudo bash -c '{
echo "#!/bin/bash"
echo "xbacklight =30"
} > /etc/lightdm/display-setup-script.sh '
then:
Code:
sudo chmod a+rx /etc/lightdm/display-setup-script.sh
then:
Code:
if 
  grep ^display-setup-script /etc/lightdm/lightdm.conf ; 
then 
  echo "Already a display-setup-script. It may already do what you need. Else please adjust manually" ; 
else 
  sudo bash -c "echo display-setup-script=/etc/lightdm/display-setup-script.sh >>/etc/lightdm/lightdm.conf" ; 
fi
Then an error occured for the last one such that there's not lightdm.conf (I don't understand why because I checked it later and it was there!). So I removed "display-setup-script.sh" and even uninstalled xbacklight. But now inside /sys/class/backlight is empty whereas it should have a link "acpi_video0" and another folder. After restarting the system, Ubuntu won't boot properly and says "the disk drive is not ready yet or present" and gives the UUID (The disk is an encrypted SSD).
I would be thankful if anyone could tell me how to fix the system since I, idiotically, don't have a backup (and the backup for the decryption key as well!)



P.S. My system is a Lenovo Thinkpad X230, Intel graphics card.