Automatic Updates

To have Ubuntu 14.04 automatically update itself and then email you a report:

Install unattended-upgrades:

sudo apt-get install unattended-upgrades mailutils

Edit /etc/apt/apt.conf.d/10periodic as shown:

APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Download-Upgradeable-Packages "1";
APT::Periodic::AutocleanInterval "1";
APT::Periodic::Unattended-Upgrade "1";

Edit /etc/apt/apt.conf.d/50unattended-upgrades as shown:

// Automatically upgrade packages from these (origin:archive) pairs
Unattended-Upgrade::Allowed-Origins {
        "${distro_id}:${distro_codename}";                                    //add this line
        "${distro_id}:${distro_codename}-security";                           //uncomment this line
        "${distro_id}:${distro_codename}-updates";                            //uncomment this line
//      "${distro_id}:${distro_codename}-proposed";
//      "${distro_id}:${distro_codename}-backports";
// List of packages to not update (regexp are supported)
Unattended-Upgrade::Package-Blacklist {
//      "vim";
//      "libc6";
//      "libc6-dev";
//      "libc6-i686";
// This option allows you to control if on a unclean dpkg exit
// unattended-upgrades will automatically run
//   dpkg --force-confold --configure -a
// The default is true, to ensure updates keep getting installed
//Unattended-Upgrade::AutoFixInterruptedDpkg "false";
// Split the upgrade into the smallest possible chunks so that
// they can be interrupted with SIGUSR1. This makes the upgrade
// a bit slower but it has the benefit that shutdown while a upgrade
// is running is possible (with a small delay)
//Unattended-Upgrade::MinimalSteps "true";
// Install all unattended-upgrades when the machine is shuting down
// instead of doing it in the background while the machine is running
// This will (obviously) make shutdown slower
//Unattended-Upgrade::InstallOnShutdown "true";
// Send email to this address for problems or packages upgrades
// If empty or unset then no email is sent, make sure that you
// have a working mail setup on your system. A package that provides
// 'mailx' must be installed. E.g. ""
Unattended-Upgrade::Mail "[email address]";                                    //uncomment this line and add your email address
// Set this value to "true" to get emails only on errors. Default
// is to always send a mail if Unattended-Upgrade::Mail is set
//Unattended-Upgrade::MailOnlyOnError "true";
// Do automatic removal of new unused dependencies after the upgrade
// (equivalent to apt-get autoremove)
Unattended-Upgrade::Remove-Unused-Dependencies "true";                         //uncomment this line
// Automatically reboot *WITHOUT CONFIRMATION*
//  if the file /var/run/reboot-required is found after the upgrade
//Unattended-Upgrade::Automatic-Reboot "false";
// If automatic reboot is enabled and needed, reboot at the specific
// time instead of immediately
//  Default: "now"
//Unattended-Upgrade::Automatic-Reboot-Time "02:00";
// Use apt bandwidth limit feature, this example limits the download
// speed to 70kb/sec
//Acquire::http::Dl-Limit "70";

Create a script somewhere, for example in /usr/local/sbin/, that contains the following code:

if [ -f /var/run/reboot-required ]; then
    echo "Automatic updates require a reboot of your computer" | mail -s "Reboot Required" [email address recipient]

Make the script executable:

chmod +x /usr/local/sbin/[name of script]

Create a cron job for the script:

crontab -e
0    8    *    *    *    /usr/local/sbin/[name of script]