Grub menu is not displayed after installing Linux (ubunt 14.04)

We often face an issue where Grub menu disappear after installing a new operating system.

By default, your GRUB is set to hide the OS selection menu on boot.

Basically, what you'll need to do is make the following change:

1. Open up a terminal (ctrl+alt+t) and then enter in the following command:   

$ sudo vim /etc/default/grub

2. Edit the file and comment below two lines (adding # before the lines)

GRUB_HIDDEN_TIMEOUT=0 
GRUB_HIDDEN_TIMEOUT_QUIET=true

becomes

#GRUB_HIDDEN_TIMEOUT=0
#GRUB_HIDDEN_TIMEOUT_QUIET=true

Save the file

3. Update the grub

$sudo update-grub

When you reboot you should see the OS Selection Menu.