linda

DEBIAN_FRONTEND=noninteractive apt-get upgrade

export DEBIAN_FRONTEND=noninteractive ; apt-get dist-upgrade -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" --force-yes

参考：
https://serverfault.com/questions/259226/automatically-keep-current-version-of-config-files-when-apt-get-install
https://unix.stackexchange.com/questions/22820/how-to-make-apt-get-accept-new-config-files-in-an-unattended-install-of-debian-f