Add Ubuntu installation on separate drive to grub

Question

My current setup includes a SATA HDD, with Xubuntu 12.10 on it. I just added an old IDE drive I had lying around to my desktop, and I used a LiveUSB to install Ubuntu 12.10 onto it. When I partitioned, I manually added the partition to the IDE HDD, since I didn't want to overwrite my Xubuntu install; when I chose the drive to install grub on, I decided to try selecting the SATA HDD, since it already had my Xubuntu install (and grub) on it.

This didn't work, since at the end of the installation it gave me a fatal error, saying it couldn't install grub on the drive. It allowed me to try selecting another drive, so I tried just installing it on the IDE HDD (where I was actually installing Ubuntu), but that gave me a fatal error as well; after that I just chose not to install grub.

Now, is there a way to add this ubuntu installation (that doesn't have grub installed on it, and is on a separate hard drive) to my current grub list (On the SATA drive, with Xubuntu), so I can choose to boot either drom a single grub screen? (i.e. so I don't have to press F+12 and select the drive to boot to load Ubuntu)

If you need more info, just let me know.

Answer 1

First, boot from the drive with Xubuntu on it. Then open a terminal and run sudo update-grub. Type in your password and press the Enter key. Now, the update-grub script will automatically add all the Linux installations it can find to the Grub menu - in your case, it would be Ubuntu and Xubuntu.

Next, reboot. You may find that you automatically boot into Xubuntu still. If you are not getting an OS selection screen at boot, hold the shift key down as you are booting.

If you want to automatically unhide the Grub menu so you don't have to hold down the shift key, boot into Xubuntu again, and then open your trusty terminal. Type in sudo gedit /etc/default/grub, press enter, type your password, and press enter again. Up comes the text editor. Change the following two lines:

GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true

To:

GRUB_HIDDEN_TIMEOUT=10
GRUB_HIDDEN_TIMEOUT_QUIET=false

Then close your editor and run sudo update-grub again. When you reboot, you should see a screen with the option to boot Ubuntu or Xubuntu.