systemctl
List units
systemctl
systemctl start/stop/restart/reload unit
systemctl status unit
systemctl is-enabled unit
systemctl mask unit – Prevent a unit from starting
systemctl unmask unit – Allow a unit to start
systemctl reboot/poweroff
Copy the unit file and create a custom version (overriding the original)
systemctl edit –full unit
Show units that failed to start
systemctl –failed
Target Runlevels
| rescue.target | Single user mode |
| multi-user.target | Multi-user, non-graphical |
| graphical.target | Multi-user, graphical |
Switching targets
systemctl isolate multi-user.target
journalctl
List entire log (in a less style interface)
journalctl
Real-time log display
journalctl -f
Show log messages relating to a specific PID
journalctl _PID=1234
Show log messages relating to a specific unit
journalctl -u unit