boot_enhancer.sh

#!/bin/bash
# boot_enhancer.sh
# also see Bootchart http://www.bootchart.org/
# source http://www.ubuntubuzz.com/2012/01/how-to-increasespeed-up-ubuntu-booting.html
first_half()
{
    sudo apt-get -y install prelink                                                 # http://ubuntuforums.org/showthread.php?t=832615
    sudo /etc/cron.daily/prelink
    sudo apt-get -y install preload                                                 # http://ubuntuforums.org/showthread.php?t=832615
    sudo sed -i 's/PRELINKING\=unknown/PRELINKING\=yes/g' /etc/default/prelink
    sudo perl -pe "s/CONCURRENCY\=makefile\n\n/CONCURRENCY\=shell\n\n/g;" \
        -0777i /etc/init.d/rc # multicore boot improvement; 0777 => process whole file so match double return (so correct match)
    sudo sed -i 's/quiet splash/quiet splash profile/g' /etc/default/grub           # grub profiling
    sudo update-grub2 
    read -p "Reboot? [Y/n]: " 
    [[ $REPLY != n && $REPLY != N ]] && sudo reboot
}

second_half()
{
    sudo sed -i 's/quiet splash profile/quiet splash/g' /etc/default/grub           # grub profiling
    sudo update-grub2 
}

create_notice()
{                                                                                   # create script for next login
    NOTICE=$(cat <<\EOF
#!/bin/bash
zenity --question --title="Finish your boot enhancement" \
    --text="Do you want to finish the boot enhancement script?"

if [[ $? ]]; then
    #same as second_half
    gksu 'sed -i 's/quiet splash profile/quiet splash/g' /etc/default/grub && update-grub2'
fi

#remove this script and autostart config
rm /usr/bin/boot_enhancer_login_note.sh 
rm ~/.config/autostart/boot-notice.desktop
EOF
    )
    loc=/tmp/boot_enhancer_login_note.sh
    echo "$NOTICE" > $loc
    chmod +x $loc 
    sudo mv $loc /usr/bin

                                                                                    # autostart it
    LOGIN=$(cat <<\EOF
[Desktop Entry]
Type=Application
Exec=/usr/bin/boot_enhancer_login_note.sh
Hidden=false
NoDisplay=false
X-GNOME-Autostart-enabled=true
Name[en_US]=boot notice
Name=boot notice
Comment[en_US]=located in home directory
Comment=
EOF
    )
    echo "$LOGIN" > ~/.config/autostart/boot-notice.desktop
    chmod 664 ~/.config/autostart/boot-notice.desktop
    echo "Notification created for next login"
}

                                                                                    #here's the prompt
echo "$(cat << \EOF
Let's make your machine boot faster!

This requires two steps, one before and one after a reboot.
This script can create a Zenity prompt for you after the reboot so you don't forget to run the second half.  

READ THIS SCRIPT before you run it.  It calls sudo multiple times.  You have been warned.

Here are your options:
[1] Run first half, reboot, and, on next login, prompt (and then run) second half.
[2] Run first half and reboot.
[3] Run second half.
[4] Get outta here.
EOF
)"

read -p "Pick your poison [1,2,3,4]: "
case "$REPLY" in
    1)
        create_notice
        first_half
    ;;
    2)
        first_half
    ;;
    3)
        second_half
    ;;
    4)
        echo "Adios!"
    ;;
    *)
        exit 1
    ;;
esac
exit;