systemctl status UNIT
Inspect a service
systemctl status nginx
systemd
systemctl restart UNIT
Restart a service
sudo systemctl restart dovecot
systemd
systemctl enable --now
Enable and start now
sudo systemctl enable --now wg-quick@wg0
systemd
journalctl -u UNIT -f
Follow logs for a unit
journalctl -u nginx -f
logssystemd
nice / renice
Adjust CPU priority
renice -n 10 -p 1234
process
kill / killall
End processes by PID/name
kill -9 1234
killall firefox
process
lsof -i
Open files/sockets (who’s listening)
sudo lsof -i :22
networkprocess
strace -p PID
Trace syscalls (debug)
sudo strace -p 1234
debug
htop
Better top (install if needed)
htop
monitor