systemctl —— 方括號表示可以省略的部分。

systemctl

行程與系統

用法

systemctl <verb> <unit>

啟動、停止和查看 systemd 服務；`enable` 只決定開機行為，想現在也啟動要用 `enable --now`，改過 unit 檔後必須 `daemon-reload`。

常用選項

選項	含義
status <unit>	Whether it is running, its PID, and the last log lines.
start / stop / restart	Act on the service now, without changing boot behaviour.
reload	Re-read the config without dropping connections, if the service supports it.
enable --now <unit>	Start it now and also start it at every boot.
daemon-reload	Required after you edit a .service file, before restarting it.
list-units --failed	Everything that failed to start.
--user	Act on your own user units instead of the system ones.

範例

sudo systemctl restart nginx

Restart the web server.

systemctl status sshd --no-pager

Print the state and recent log lines without opening a pager.

sudo systemctl enable --now docker

Start Docker and make it come back after a reboot.

看什麼在跑、什麼在吃機器。先弄清是什麼，再決定殺不殺。

怎麼看

Q. systemctl 是做什麼的？

啟動、停止和查看 systemd 服務；`enable` 只決定開機行為，想現在也啟動要用 `enable --now`，改過 unit 檔後必須 `daemon-reload`。

Q. 怎麼寫？

systemctl <verb> <unit> —— 方括號表示可以省略的部分。

Q. 值得記的選項有幾個？

這裡列了 7 個，完整列表在 man systemctl。這條命令屬於行程與系統。