I need to reboot an Ubuntu Server 16.04, from terminal, where the sbin folder is unreadbale due to a disk IO error.

Now if I run shutdown -r I get command not found, as the sbin folder is not readable, also many other services are unresponsive due to this issue.

Is there another way to call the shutdown -r without calling anything in the sbin folder?

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    init 6 might work, tells the server to change to runlevel 6 (which is reboot) – Panki Aug 27 '19 at 10:00
  • nothing to do: Failed to start reboot.target: Connection timed out See system logs and 'systemctl status reboot.target' for details. It seems a serious problem and I have to go there physically to restart and fix the machine. I hope I'll be able to clone the drive! – Giox Aug 27 '19 at 10:09
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    Note that the (re)boot will probably fail. It is unlikely that a system with a damaged /sbin will boot. Try init 0 to shutdown it. – andcoz Aug 27 '19 at 10:10
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    I don't think that reboot is a good option in this case. Chances are, the server won't start afterwards. You'd better start backing up data from the server and get ready for hardware replacement and resetup. – deimos Aug 27 '19 at 10:22

The "magic SysRq" interface can be accessed through procfs to ask the kernel to reboot.

echo 1 > /proc/sys/kernel/sysrq # to enable magic SysRq
echo b > /proc/sysrq-trigger    # to reboot, same as if you had pressed Alt-SysRq-B

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