Linux System single user mode

The most common use is to change the root password in single-user mode
Run Init 1 under Run Level 3
but it doesn't seem to make much sense to run like this.
so you can only restart reboot to enter a single user
when it starts, press any key to enter the interface within 3 seconds.
you can press the E key to enter edit mode
press A To change the kernel selection
Press C to enter command line mode
we'll press E to edit. Press the arrow key to select the second row for editing
1 or s/s/single then enter and press B to start .
Run RunLevel View
passwd Change Password
after setting the input reboot restart

Linux System single user mode