Update

Package lists and upgrades

apt-get update

Gets the update list.

apt-get upgrade

Applies the update.

apt-get dist-upgrade

Upgrades packages. Dangerous: it will force installation of new packages and remove old packages. For non-auto-updating packages, it intelligently updates dependency packages.

apt full upgrade

Performs all of the above.

apt autoremove

Removes lingering packages.

apt --fix-broken install

apt-get update && apt-get upgrade

Caution: dist-upgrade can install new packages and remove old ones.

Major update

Example: 12 > 14.

do-release-upgrade

apt-get install update-manager-core

Alternate SSH — open port 1022:

iptables -I INPUT -p tcp --dport 1022 -j ACCEPT

May throw: bad network or server error.

Repair lists

apt-get clean
cd /var/lib/apt
mv lists lists.old
mkdir -p lists/partial
apt-get clean
apt-get update

Release upgrades file

/etc/update-manager/release-upgrades values: normal | lts | off.

Message

/var/lib/ubuntu-release-upgrader/release-upgrade-available