Hi,
The documentation instructs to use systemctl reboot to restart the system.
https://docs.oracle.com/cd/E52668_01/E54669/html/ol7-s3-bootconf.html
The filesystems shows /sbin/reboot is a symbolic link to systemctl:
# ls -l /sbin/reboot
lrwxrwxrwx. 1 root root 16 Apr 27 13:57 /sbin/reboot -> ../bin/systemctl
Apparently, systemctl checks how it's involved and systemctl reboot and reboot are presumably the same. However, the documentation does not explain this. Why do instructions not use reboot and poweroff? Is there any difference?
Also shutdown is a symbolic link to systemctl.
$ ls -l /sbin/shutdown
lrwxrwxrwx. 1 root root 16 Apr 27 13:57 /sbin/shutdown -> ../bin/systemctl
So, we can still use shutdown -r now to restart the system. I find that confusing.
It's important that a reboot goes through the usual shutdown procedures. According to man reboot, I can specify the --force option twice (reboot -f -f) to restart the system without using the shutdown manager. If I remember correctly, on some Unix systems, reboot was only safe to use in single user mode/
Thanks!