Graphical reboot-into-OS chooser for GRUB2

grub-reboot.sh

#!/bin/bash
#
# Show a list of GRUB2 menu entries, and reboot into the chosen one.
#
# Your /etc/default/grub MUST have GRUB_DEFAULT set to "saved".
# If you make this change, run update-grub as root to apply it.
# To learn more, read: https://wiki.debian.org/GrubReboot
#
# Requirements:
# * zenity
# * grub2

# Build list of menu entries into zenity command
cmd='zenity --list --title="Reboot into specific OS" --column="Menu Entry" --width=400 --height=400'
while read e
do
  echo "Adding $e"
  cmd="$cmd \"$e\""
done <<< "$(grep -oP "^menuentry '[A-Za-z0-9()/ \-\.+,]+'" /boot/grub/grub.cfg | cut -c 12- | rev | cut -c 2- | rev)"

# Display list prompt using zenity
choice=$(eval "$cmd")

# Reboot into selection
if [ -n "$choice" ] # Check if there actually is a selection
then
  gksudo grub-reboot "$choice" && reboot
fi