Dual boot: changing the Grub's delay

Grub is a boot loader used by Ubuntu. When a multi-boot is configurated, Grub waits 10 seconds before launching the default OS.

To change the timeout, edit with sudo rights etc/default/grub and change the entry GRUB_TIMEOUT=XX (-1 will display the menu untill the user chooses a selection); then run sudo update-grub in the console.