/usr/lib/systemd/system
/run/systemd/system
/etc/system/system

启动:service name start ==> systemctl start name.service
停止:service name stop ==> systemctl stop name.service
重启:service name restart ==> systemctl restart name.service
重载或重启: systemctl reload-or-restart name.service
状态:service name status ==> systemctl status name.service
条件式重启:service name condrestart ==> systemctl try-restart name.service
开机自启: chkconfig name on ==> systemctl enbale name.service
取消开机自启:chkconfig name off ==> systemctl disable name.service
禁止设置开机自启:systemctl mask name.service
取消上面的设定: systemctl unmask name.service
查看所有服务的开机自启状态：chkconfig --list ==> systemctl list-unit-files --type service
查看服务器是否开机自启: systemctl is-enabled name.service
级别切换： init N ==> systemctl isolate name.target
查看级别: runlevel ==> systemctl list-units --type target
获取默认运行级别: /etc/inittab ==> systemctl get-default
修改默认运行级别: /etc/inittab ==> systemctl set-default name.target
切换至紧急救援模式: systemctl rescue
切换至emergency模式:systemctl emergency （比rescue 更彻底）
关机: systemctl halt,systemctl poweroff
重启: systemctl reboot
挂起:systemctl suspend
快照: systemctl hiberate
快照并挂起: systemctl hybrid-sleep
查看服务依赖关系:systemctl list-dependencied name.service
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以下是在 systemctl enable name.service状态下 或者是服务已启动状态 才有效

查看服务是否启动: systemctl is-active name.service
查看已经已经启动的服务
systemctl list-units --type service
查看所有服务:
systemctl list-units --type service --all

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