core/grub2/grub2.install

infodir=usr/share/info
filelist=(grub.info grub-dev.info)

show_important_message() {
  echo -e "\033[0;31m IMPORTANT"
  echo -e "\033[0;0m  Run \033[0;32m 'grub-install /dev/sda --no-floppy' \033[0;0m as root for installing in MBR"
  echo -e "\033[0;0m  Run \033[0;32m 'grub-mkconfig -o /boot/grub/grub.cfg' \033[0;0m as root for generating grub.cfg"
  echo -e "\033[0;0m  Also you can run \033[0;32m 'update-grub' \033[0;0m as root for generating grub.cfg"
}

delete_symlinks() {
  if [ `readlink /boot/kernel26.img` ] ;
  then
    echo "removing backward-symlink"
    rm -v /boot/kernel26.img
  fi
  if [ `readlink /boot/kernel26-lts.img` ] ;
  then
    echo "removing backward-symlink"
    rm -v /boot/kernel26-lts.img
  fi
  if [ `readlink /boot/vmlinuz26` ] ;
  then
    echo "removing backward-symlink"
    rm -v /boot/vmlinuz26
  fi
  if [ `readlink /boot/vmlinuz26-lts` ] ;
  then
    echo "removing backward-symlink"
    rm -v /boot/vmlinuz26-lts
  fi
}

post_install() {
  if [ -f /boot/grub/grub.cfg.pacsave ]; then
    echo "Copying /boot/grub/grub.cfg.pacsave to /boot/grub/grub.cfg"
    install -Dm644 /boot/grub/grub.cfg.pacsave /boot/grub/grub.cfg
  fi

  echo -n "Generating grub.cfg.example config file... "
  grub-mkconfig -o /boot/grub/grub.cfg.example 2> /dev/null
  echo "done."

  for file in ${filelist[@]}; do
    install-info $infodir/$file.gz $infodir/dir 2> /dev/null
  done
  delete_symlinks
  show_important_message
}

post_upgrade() {
  for file in ${filelist[@]}; do
    install-info $infodir/$file.gz $infodir/dir 2> /dev/null
  done
  delete_symlinks
  show_important_message
  if [ -s /boot/grub/grub.cfg ]
  then
     update-grub
  fi     
}

pre_remove() {
  for file in ${filelist[@]}; do
    install-info --delete $infodir/$file $infodir/dir 2> /dev/null
  done
}