When you start Kali, the grub boot menu comes up which waits for around 5 seconds before booting. Now if there are other oses alongside kali then the grub menu is useful. However if kali is the only os on the system, or for example kali is running inside virtualbox then it is of little use for the grub menu to wait.
So to remove the grub menu waiting and boot instantly, edit the file /etc/default/grub.
root@kali:~# leafpad /etc/default/grub
Edit the value of GRUB_TIMEOUT to 0. Also add 2 entries called GRUB_HIDDEN_TIMEOUT and GRUB_HIDDEN_TIMEOUT_QUIET.
# If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' GRUB_DEFAULT=0 GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=0 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet" GRUB_CMDLINE_LINUX="initrd=/install/gtk/initrd.gz"
Save the file and issue the update-grub command.
root@kali:~# update-grub Generating grub.cfg ... Found background image: /usr/share/images/desktop-base/desktop-grub.png Found linux image: /boot/vmlinuz-3.7-trunk-amd64 Found initrd image: /boot/initrd.img-3.7-trunk-amd64 done
Now when you start Kali, it will boot straight, without the grub menu waiting.
