apt-get - package manager for Debian and Ubuntu

Options you will use

update

Refresh the package lists. Downloads NO packages. Always first.

upgrade

Install newer versions of everything installed.

install PKG

Install a package and its dependencies.

remove PKG

Remove a package but keep its config files.

purge PKG

Remove the package and its config.

autoremove

Remove dependencies nothing needs any more (old kernels live here).

list --installed / --upgradable

What is installed, or what has an update.

show PKG, search TERM

Package details, and search the descriptions.

-y, --yes

Assume yes. Required in scripts and CI.

Examples

$ sudo apt update && sudo apt upgrade -y

the pair, in that order

$ sudo apt install -y tree jq

the tools this course uses

Gotchas

• apt needs root for anything that writes: without sudo you get "Could not open lock file /var/lib/dpkg/lock-frontend - Permission denied".

Taught in

• 18.6 kubeadm init and join: what they actually do