Ubuntu notes

As of 2025 Q2 Ubuntu server dist upgrades require a package which is not installed in minimal Ubuntu install processes. To install the automating distribution upgrader (note 1):

 $ sudo apt install ubuntu-release-upgrader-core

To start the distribution upgrade:

 $ sudo apt do-release-upgrade

When disk space is too small on a partition . . .

• https://runcloud.io/blog/used-disk-space-linux#using-built-in-utilities-to-check-disk-usage

 $ du -s * | sort -nr | head -n10

To safely remove an old kernel image and related files from /boot . . .

Dist upgrade 1804 to 2004

After a dist-upgrade from 18.04 LTS to 20.04 LTS may be necessary to reconfigure some elements of apache2 webserver, and may be necessary to uninstall nginx web server. Some elements needing help to bring apache2 back up:

$ sudo apt install libapache2-mod-php7.4

$ sudo a2dismod php7.2

$ sudo a2enmod php7.4

$ sudo systemctl restart apache2

Notes

(1) https://www.cyberciti.biz/faq/ubuntu-bash-do-release-upgrade-command-not-found/