Command manuals for management

adduser, addgroup - add or manipulate users or groups

apt - command-line interface

apt-get - APT package handling utility -- command-line interface

deluser, delgroup - remove a user or group from the system

dpkg - package manager for Debian

flatpak - Build, install and run applications and runtimes

groupadd - create a new group

groupdel - delete a group

groupmod - modify a group definition on the system

logrotate ‐ rotates, compresses, and mails system logs

poweroff, reboot, halt - Power off, reboot, or halt the machine

shutdown - Halt, power off or reboot the machine

snap - Tool to interact with snaps

tasksel - a user interface for installing tasks

ucf - Update Configuration File: preserve user changes in configuration files

useradd - create a new user or update default new user information

userdel - delete a user account and related files

usermod - modify a user account