SysV啟動級別與Systemd目標對照表

0  runlevel0.target, poweroff.target  
1, s, single  runlevel1.target, rescue.target  
2, 4  runlevel2.target, runlevel4.target, multi-user.target  
3  runlevel3.target, multi-user.target  
5  runlevel5.target, graphical.target  
6  runlevel6.target, reboot.target  
emergency  emergency.target 

相關指令
systemctl isolate graphical.target #切換啟動級別