针对RHEL操作系统破解root密码
1、重启虚拟机 按e进入更改配置
2、在linux16末尾加上 rd.break,ctrl+x执行（，不用加进去）
3、写入mount -o remount, rw /sysroot
4、chroot /sysroot
5、passwd root
6、输入新密码：
7、确认密码
8、touch /.autorelabel touch: 1.改变文件的时间 2.创建一个文件
9、exit
10、exit
重启：reboot
关机：shutdown -h now，poweroff(前者会先保存再关机。 后者为强制关机不会保存)
界面：
英文注释：
1.Reboot the system.
2.Interrupt the boot loader count down by pressing anykey.
3.Move the cursor to the entry that needs to be booted.
4.Press “e” to edit the select edentry.
5.Move the cursor to the kernel command line(the line that start swith linux16.
6.Append rd.break
7.Press Ctrl+x to start.
8.Remount /sysroot as read-write.
switch_root:/# mount -o remount,rw /sysroot
9.Switch into a chroot jail, where /sysroot is treated as the root of the filesystem tree
switch_root:/# chroot /sysroot
10.Set a new root password:
sh-4.2# passwd [root] (change the root password)
or
sh-4.2# passwd -d root (delete the root password)
11.Make sure that all unlabeled files (including/etc/shadow at this point)get relabeled during boot.
sh-4.2# touch /.autorelabel
12. sh-4.2# exit
13. switch_root:/# exit