Apt

Debian/Ubuntu package manager

 

Unattended upgrades

• https://pimylifeup.com/unattended-upgrades-debian-ubuntu/

Disable unattended upgrades

In /etc/apt/apt.conf.d/20auto-upgrades

APT::Periodic::Unattended-Upgrade "0";

HOWTO

Extract files from .deb

dpkg-deb

Pin a version

• Pinning Howto

FAQ

Show version of packages before installing

apt-get -s install somepackage

or

apt install madison-lite
apt-cache madison somepackage

or

apt-show packagename

have been kept back

Usually means you should run

apt install <kept-back-package>

or

apt upgrade packagename

otherwise

 apt dist-upgrade

Unable to correct problems, you have held broken packages.

Try

dpkg --get-selections | grep hold

What packages depend on package

apt-cache rdepends --installed libc6-dev

Clear cache

apt-get clean

Could not handshake: The TLS connection was non-properly terminated.

try http instead of https

Depends: but it is not going to be installed

First try

apt-get update && apt-get upgrade

Which services should be restarted?

That's from needrestart

Prevent restarting all services when installing a package

NEEDRESTART_MODE=i apt install somepackage

What repository provides package

apt policy <packagename>

Error messages

Key is stored in legacy trusted.gpg keyring

Check apt-key is deprecated

Certificate verification failed: The certificate is NOT trusted.

try

deb [trusted=yes] ...

in sources.list, but things might be worse than that, in case of launchpad change to

https://ppa.launchpadcontent.net/