Change Default OS and Timeout Of Dual Boot

If you have more than one operating system installed, then at the start up you see the boot screen asking you to select the OS you like to boot.When you install Ubuntu or any other Linux OS with Windows OS the boot loader is gene rally changed with the Grub boot loader.

DEFAULT VIEW OF GNU GRUB BOOT LOADER WITH ONLY 1 OS INSTALLED

There are many versions of Grub Boot Loader. The Ubuntu 10.04LTS or later use 1.98 or later. You can check the grub version by using this command in Terminal.

grub-install -v

This method will only work if your grub version is 1.98 or later Despite The linux distro you are using.

Now here we will be going to change the default OS and the time out. The grub display setting file can be found in the directory / etc / default . Remember to sign in as superuser. For sign in as super user in Ubuntu you can use command sudo su .

The file we are gonna make changes is grub. Just use this command 

vim / etc / default / grub

On the 6th line you will get GRUB_DEFAULT = 0 , get into the insert mode by pressing i and change the 0 to your OS choice position in the display list. Mine is set to 5 as Window's OS is placed at 6th position in the boot list and the display starts counting from 0 by default, so from 0 at its fifth position.

Now, if you want to change the time-out you can just change the time specified by GRUB_TIMEOUT on line number 9 After you have done changes to your grub file just save it. For saving and quitting use : wq!

File look like this after making changes

The last step is to update the grub configuration files. Just use this command update-grub in the terminal window and you are done. Now you can boot to your favorite OS without Selecting it at the boot time.