Command option Sample:systemctl default

Search command sample in the internet.It is the result.

systemctl default systemctl default mode    Systemd Cheat Sheet : Linux - ETHICAL HACKING : http://www.ethicalhackx.com/systemd-cheat-sheet-linux/
systemctl default [root    systemd: how to get current target - kde - Fedora Mailing-Lists : http://lists.fedoraproject.org/archives/list/kde@lists.fedoraproject.org/thread/MGFTNDO6HJZZZV4BEONLSIRRXVHCFTTZ/
systemctl default mode    Systemd Cheat Sheet : http://highon.coffee/blog/systemd-cheat-sheet/
systemctl default or    centos 7 emergency mode dependency failed for local file systems : http://gree2.github.io/linux/2017/12/13/centos-7-emergency-mode-dependency-failed-for-local-file-systems
systemctl default    LEAP 42.3 Black Screen of death with leap 42.3 discraceful : http://forums.opensuse.org/showthread.php/478248-systemctl-does-NOT-stop-the-GUI-unlike-init

search Google

https://www.google.com/#q=systemctl default