How to change the root password in linux single-user mode

Enter single user mode:

1. grub

After entering the startup screen, press "e", move the cursor to the line of kernel..., then press "e", add a space single at the end of the line of kernel, and press Enter.

Press "B" to start the system, that is, enter the single-user mode,

At this time, you can use the passwd command to change the password.

Passwd root

Restart reboot after modification.

2. lilo

Enter the lilo command line mode, and input linux single to enter the single user mode.

Passwd...

If grub/lilo has a password, remember it. If you forget the password for grub/lilo, you only need to use rescue mode.