在比較新的 Linux, Service Manager 已用 systemctl 取代舊的 chkconfig, service
chkconfig --list = systemctl list-units or systemctl list-unit-files
chkconfig sshd on = systemctl enable sshd.service
chkconfig sshd off = systemctl disable sshd.service
service sshd start = systemctl start sshd.service
service sshd stop = systemctl stop sshd.service
service sshd restart = systemctl restart sshd.service
service sshd status = systemctl status sshd.service
