Linux is a multi-user system that runs many programs at once. This module shows you how to control both sides of that: who is allowed to use the machine, and what is currently running on it. These are core skills for anyone administering a server or troubleshooting a slow or misbehaving system.
It starts with users and groups: how to see who you are, create and
modify accounts with useradd, passwd, and usermod,
and organize people with groups. Next comes switching users and using
sudo to run commands with elevated privileges safely. From there
you'll view processes with ps and top, then
control them with kill, signals, and nice. It
closes with background jobs, using &, jobs,
fg, bg, and nohup.
Practice on a test machine or virtual machine, and be careful with kill and
account changes on a system you care about. When you're comfortable, continue on to
Package Management.
See who you are with whoami and id, create and modify accounts with useradd, passwd, and usermod, and manage groups with groupadd and gpasswd.
Use su to change users and sudo to run single commands as root, and learn how the sudoers file controls who gets that power.
List running processes, read PIDs, CPU, and memory columns, and monitor the system live with ps, top, and htop.
Stop or restart processes with kill, killall, and pkill, understand signals such as SIGTERM and SIGKILL, and adjust priority with nice and renice.
Run commands in the background, suspend and resume them with Ctrl+Z, fg, and bg, and keep them running after logout with nohup.