systemd : run my script before shutdown.

ref:

• run script with systemd before shutdown

所以試試看：
先產生..

# cat /etc/systemd/system/runmyshutdown.service 
[Unit]
Description=Run my custom task at shutdown
DefaultDependencies=no
Before=shutdown.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/myshutdown.sh
TimeoutStartSec=0

[Install]
WantedBy=shutdown.target

還有測試的 script:

# cat /usr/local/bin/myshutdown.sh 
#!/bin/bash
/bin/touch /data/sssss

然後..

# systemctl daemon-reload
# systemctl enable runmyshutdown
Created symlink /etc/systemd/system/shutdown.target.wants/runmyshutdown.service → /etc/systemd/system/runmyshutdown.service.

原來沒有 /etc/systemd/system/shutdown.target.wants 這個目錄。
因為 WantedBy 的關係，所以新 create。

測試，reboot 後，到 /data 去看，果然有 ssss，所以是成功了。