So, the following method is good because it is done very quickly and allows you to change the password to one or more users. On my operating system as most people have only one user, therefore the password root changing along with the password of the Main user.
That is, if I change the password to my single user l4l, then user root will automatically change the password. On other operating systems, I think the user root as separately. In any case I am not interested in, the main thing here everything is convenient and WORKS))))
Let's start, we need to get into the boot menu of GRUB. When the computer boots, hold down the "SHIFT" key. In the grub boot loader to select the desired OS and press "E" to edit the boot.
Next we need at the end of the kernel line, after quiet splash add rw init=/bin/bash and press "F10" to boot.
In this case, after the kernel is loaded, the control immediately proceeds to bash that allows you to change the passwords for all users. A working example can be seen in the picture below. Just write the command:
where Username is the login name of the user. Then simply enter the new password.
Restart the computer and can use the new password.
Recently read about another method of password recovery. Starts the same way, we need to enter GRUB
By default in the restore mode, the file system is read-only and you can't just overwrite the user's password, but knowing a needed command you can fix it.
Enter the following command, which will open write access
Next you need to enter the command to change the password
mount -o rw,remount /
The word “yourusername”, I mean the user name in your system (On my screenshot - shekin)
Voila, now I can't log in under my old password
May the Force be with you,