daemon-reload: Reload the configuration file of a service , If a new service is installed , Belong to systemctl
Administration , If the server configuration file for the new service takes effect , Need to reload .


init and systemd The difference of command , Brief introduction :



systemctl --help  view help !!!!!!!


systemctl  enable  |  disable |  is-enabled  | status  | is-active  unit

systemctl   get-default    |  set-default 
|           islate Online switching mode   

systemctl reload-daemon  Load new unit configuration file   

systemd  Of unit Configuration file location for   :  redhat series : catalog   /usr/lib/systemd/system/ lower  

enable It's in   /etc/systemd/system/  Under this directory do unit Soft chain of configuration file :