#!/bin/sh -e

grub=/etc/default/grub
cat $grub | while read line; do
    if echo $line | grep GRUB_CMDLINE_LINUX_DEFAULT >/dev/null; then
        arguments=$(echo $line | cut -d\" -f2 | sed 's/init=[^ ]*//' | sed 's/^[\t ]*//' | sed 's/[\t ]*$//' | tr -s ' ')
        echo GRUB_CMDLINE_LINUX_DEFAULT=\"$arguments $(read-init)\" >> $grub.new
    else
        echo $line >> $grub.new
    fi  
done
mv $grub.new $grub

update-grub && \
    echo "init successfully updated.  please reboot to start using the selected init." || \
    echo "init not updated. update-grub command failed above."
