I'm getting this error message whathever I do:

$ sudo reboot
bash: /usr/bin/sudo: Input/output error
$ reboot
bash: /sbin/reboot: Input/output error

It's a hardware failure according to this question. Is there anyway that I can reboot the machine without physically pull the the plug. The machine is not close to me. I can SSH into the machine. ls, pwd, echo, cat and some other apps are working. Things like ps, vim and killall are not working.

  • What commands can you use? Can you become root? All solutions will require root access so if you can't run sudo, can you at least su? Can you run shutdown? How about init?
    – terdon
    Apr 12, 2014 at 20:04
  • No, I can't be root. I didn't set Ubuntu's root password! :(
    – Mohsen
    Apr 12, 2014 at 20:12
  • @Mohsen Setting a root password would not make any difference. You'd have to run su instead of sudo, but you'd run into the same problem. If you have no way to gain root access, you cannot reboot. Apr 12, 2014 at 23:45

1 Answer 1


If you have root access, you can try to do this:

# echo b > /proc/sysrq-trigger

(that will immediately reboot the system without syncing or unmounting your disks.)

Unfortunately, I do not think there is a way to reboot without root privileges.

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