我忘记了Linux系统的密码，该怎么做？

我忘记了Linux系统的密码，该怎么做？

简单的回答，就是使系统进入单用户模式，或者叫安全模式。

详细的回答，就是介绍如何进入单用户模式。
http://www.cyberciti.biz/faq/linux-reset-forgotten-root-password/

My boot loader is GRUB (see
LILO boot loader below)

)Following is the procedure to reset root password if you are using GRUB as a boot loader:

Select the kernel
Press the e key to edit the entry
Select second line (the line starting with the word kernel)
Press the e key to edit kernel entry so that you can append single user mode
Append the letter S (or word Single) to the end of the (kernel) line
Press ENTER key
Now press the b key to boot the Linux kernel into single user mode
At prompt type passwd command to reset password:
You need to mount at least / and other partitions:

# mount -t proc proc /proc

# mount -o remount,rw /

Change the root password, enter:

# passwd

Finally reboot system:

# sync

# reboot

My boot loader is LILO

At LILO boot loader type linux single and press [ENTER] key:

Boot: linux single

When you get the # prompt you will need to type passwd root to reset password:

# passwd

Reboot system:

# sync

# reboot