重置树莓派的密码

How To Reset A Forgotten Raspberry Pi Password

I’ve got a Raspberry Pi running in my garage as part of a security system. It’s been running for so many months that I forgot the password so I was unable to access it via SSH.

Luckily there is was a technique that I could use to reset the password and get it back up and running. You need physical access to the SD card, a separate PC and the ability to connect your Pi to a monitor and keyboard. I used a Windows PC but this should work fine on a Mac or Linux machine.

Step 1 – Grab The SD Card

Power down the Pi and remove the SD card. Insert it into your PC.

Step 2 – Edit cmdline.txt

The boot partition should be visible and contain a file named “cmdline.txt”. Edit this file in a text editor and add the following to the end of the existing text :

init=/bin/sh

If the original content was :

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

it should now look like :

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait init=/bin/sh

Make sure it is all one line! Save the text file and eject the SD card from the PC.

Step 3 – Reset the Password

Insert the card into a Pi that is connected to a monitor and keyboard. Power up the Pi. There may be a delay but you should be presented with a flashing cursor.

At the prompt type the following command :

mount -rw -o remount /

then

passwd pi

You will then be prompted for a new password. Enter it carefully and press the [Return] key. It will now ask you to retype the password.

Reset Lost Password

The password has been changed.

Now type the following commands :

sync

exec /sbin/init

The Pi will continue to boot and return you to the normal command line prompt.

Shutdown the Pi and power it off.

sudo halt

Step 4 – Edit cmdline.txt

Using the PC edit the “cmdline.txt” file again and remove the “init=/bin/sh” text you added in Step 2.

You can now return the SD card to your Pi, reboot and use the new password.

Article from http://www.raspberrypi-spy.co.uk/2014/08/how-to-reset-a-forgotten-raspberry-pi-password/