Debian 系で unattended-upgrades を有効にする場合の追加設定 (メール通知, autoremove, autoclean, 再起動) ref: http://qiita.com/kitsuyui/items/11b4c0ebb9d1d2181853

20auto-upgrades

APT::Periodic::AutocleanInterval "1";

50unattended-upgrades

Unattended-Upgrade::Automatic-Reboot-Time "02:00";

file0.txt

$ sudo apt-get install -y unattended-upgrades
$ sudo dpkg-reconfigure -plow unattended-upgrades
(TUI が表示されるので <Yes> を選択する)

file1.txt

$ sudo editor /etc/apt/apt.conf.d/50unattended-upgrades

file2.txt

// 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. "user@example.com"
//Unattended-Upgrade::Mail "root";

file3.txt

Unattended-Upgrade::Mail "じぶんのメールアドレス";

file5.txt

$ sudo apt-get install -y mailutils

file6.txt

$ sudo editor /etc/apt/apt.conf.d/50unattended-upgrades