爱华网#前者是符号链接指向了后面的targetrunlevel3.target -> multi-user.targetrunlevel5.target -> graphical.target
#切换到：运行级3#这两种都可以systemctl isolate multi-user.targetsystemctl isolate runlevel3.target
#切换到：运行级5#这两种都可以systemctl isolate graphical.targetsystemctl isolate runleve5.target
#修改开机默认运行级别systemd使用链接来指向默认的运行级别。由/etc/systemd/system/default.target文件中决定切换到运行级3：先删除:/etc/systemd/system/default.targetln -sf /lib/systemd/system/multi-user.target/etc/systemd/system/default.targetln -sf /lib/systemd/system/runlevel3.target/etc/systemd/system/default.target#用这个也可以systemctl set-default multi-user.target
切换到运行级5ln -sf /lib/systemd/system/graphical.target/etc/systemd/system/default.targetln -sf /lib/systemd/system/runlevel5.target/etc/systemd/system/default.target#用这个也可以systemctl set-default graphical.target
#查看当前运行的级别runlevel //仍然可用
