Adding custom entries to GRUB 2

The configuration files of the bootloader GRUB 2 are located in the folder /etc/grub.d/. To add custom entries to the bootloader, the file 40_custom has to be modified. Following the unmodified version of this file is shown.

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

Custom menu entries can be added to the end of this file. An examplary modification of the file 40_custom, with two entries to reboot or halt the system, is shown below.

#!/bin/sh
echo "Adding custom menu entries." >&2
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

menuentry "Reboot System" {
reboot
}

menuentry "Halt System" {
halt
}

To take effect the changes you have to run the command update-grub as root.