systemctl manages systemd units: services (.service), sockets, timers, and mounts. start and stop apply immediately; enable creates symlinks so units start at boot. After editing unit files, run daemon-reload before restarting. status shows cgroup, memory, and recent log lines. edit --full or drop-ins under /etc/systemd/system/foo.service.d/ override vendor defaults.
| Action | Command | Note |
|---|---|---|
| Reload units | systemctl daemon-reload | Required after unit edits |
| Boot order | systemctl enable --now svc | Enable and start together |
| Failures | systemctl --failed | Quick post-boot health check |
Related
sysadmin essentials, process management, sudo, security commands