How To Change Boot Order/Set Default Boot OS In Ubuntu

Just a few steps. Let's start!

this step without GUI Application

1. Open ur terminal (shortcut: CTRL+ALT+T)
2. type this command to let u know menu entry for ur grub

grep menuentry /boot/grub/grub.cfg

if ur laptop/pc dual booting with Windows, the output should be like this:

know ur windows name:

3. make copy ur file with this command:
cp  /etc/default/grub /etc/default/grub.bak

4. edit ur default grub with run this command
nano /etc/default/grub

the output should be like this:

focus on line below:

edit like this:

u can change grub timeout by replace this code:

5. save ur work and update ur grub with this command:
and the output should be like this:

and the last step is reboot ur laptop/pc

thanks for reading
any question? just comment