Ubuntu forgot password and cracked Login Password

If anyone says that his Linux has never encountered a "difficult problem", I think it is untrusted. Even the most friendly Window XP on the operating interface often encounters various problems, some problems can be solved only by replacing the hardware! Linux is also like this, and its freedom is also increasing the frequency of problems. Of course, it is also because of the open source features of Linux. No matter what the problem occurs, you can find the crux of the problem at the source code level. This is the charm of Linux.

1. Get the root permission without logging on

If the GRUB Password is not set, we can use the simplest method. First, start the computer and wait for the GRUB menu. If the GRUB menu is hidden, Press Esc to bring it up and select Ubuntu, kernel 2.6.12-* (recovery mode), that is, "recovery mode", Press Enter to start. Another method is to use the Ubuntu installation disk to obtain the root permission and start the computer with the Ubuntu installation disk. When "boot:" is displayed, enter "rescue"

Boot: rescue

Follow the on-screen prompts to obtain the root permission.
Then # passwd root New Password

# Vi/etc/X11/TPD/gestational disease. conf # Open the gnome configuration file, input: AllowRoot press enter in the last line mode, find AllowRoot = false, change false to true, save and exit. JHYLinux Alliance
JHYLinux Alliance
After that, you can log on to the system as the root user. If you want to disable the root account, run the following command: jHYLinux Alliance
JHYLinux Alliance
$ Sudo passwd-l root

2. Get the root permission by changing the kernel startup parameters

Start the computer and wait for the GRUB menu. If the GRUB menu is hidden, Press Esc to call it up. If the GRUB Password is set, press p to unlock it. For example, if we select Ubuntu, kernel 2.6.12-8-386, press e to edit startup parameters before startup, select kernel/boot/vmlinuz-2.6.12-8-386 root =/dev/hda2 ro quiet splash, press e to edit the selected Start Menu item, and add rw init =/bin/bash at the end of the parameter, that is, change it to the following command line:

Grub edit> kernel/boot/vmlinuz-2.6.12-8-386 root =/dev/hda2 ro quiet splash rw init =/bin/bash

Start by B.

3. the root user/Master user password is missing.

Follow the first item: if you do not log on, after obtaining the root permission, enter the following command in the command line:

Passwd root follow the prompts and enter the password twice to set the root user password.

To change the primary user password:

Passwd system_main_username

Follow the prompts and enter the password twice.

Source: aspx "> http://blog.csdn.net/iori97king/archive/2008/01/09/2032641.aspx