systemctl try-restart 和 systemct

2022-11-08 遇到的一点小问题

最近做某个功能查文档，刚好看到systemctl 中文手册和journalctl 中文手册，记录两个个之前没用到的功能。

systemctl try-restart systemd-timesyncd
有启动才重启，否则不重启。和restart不一样。
之前都是systemctl status systemd-timesyncd > /dev/null 2>&1;echo $?,判断0 -eq $?``restart才重启。

try-restart

systemctl cat systemd-timesyncd
直接查看服务文件
之前都是systemctl status systemd-timesyncd,从信息里获取路径，再cat读取cat /usr/lib/systemd/system/systemd-timesyncd.service。

cat

.

systemctl daemon-reload
测试的时候经常会修改服务文件，修改完要执行systemctl daemon-reload再restart。经常忘了怎么拼，顺便记录一下。

daemon-reload

echo "$(systemctl status systemd-timesyncd)"
之前的固件，在控制台执行命令systemctl status systemd-timesyncd，能看到的信息比较多：

status
最新的固件，只能看到一点点信息：
status
不过还好使用echo能看到比较多的信息，输出信息里有中文，使用这个也能正常在控制台显示。

[root@wannoo ~]# echo "$(systemctl status systemd-timesyncd)"
* systemd-timesyncd.service - Network Time Synchronization
     Loaded: loaded (/usr/lib/systemd/system/systemd-timesyncd.service; disabled; preset: enabled)
     Active: active (running) since Thu 2023-03-23 03:14:18 UTC; 35min ago
       Docs: man:systemd-timesyncd.service(8)
   Main PID: 1028477 (systemd-timesyn)
     Status: "Contacted time server 185.209.85.222:123 (pool.ntp.org)."
      Tasks: 2 (limit: 4563)
     Memory: 1.0M
     CGroup: /system.slice/systemd-timesyncd.service
             `-1028477 /usr/lib/systemd/systemd-timesyncd

Mar 23 03:14:18 wannoo systemd[1]: Starting Network Time Synchronization...
Mar 23 03:14:18 wannoo systemd[1]: Started Network Time Synchronization.
Mar 23 03:14:18 wannoo systemd-timesyncd[1028477]: Contacted time server 185.209.85.222:123 (pool.ntp.org).
Mar 23 03:14:18 wannoo systemd-timesyncd[1028477]: Initial clock synchronization to Thu 2023-03-23 03:14:18.801809 UTC.
[root@wannoo ~]#