How do I restart Linux (Ubuntu) from the command-line?

Question

Because of my problem with mouse-clicks being ignored in Ubuntu, I want to restart from the command-line. (I have an open Terminal, and the keyboard is not ignored.)

How do I restart a computer running Linux (or more specifically Ubuntu) from the command-line?

Solution 1

There's a few ways:

sudo reboot

sudo init 6

sudo shutdown -r now

Solution 2

If you've got freedesktop-compliant session manager, you can use DBus to invoke restart from inside the X session. The command goes:

dbus-send --system --dest=org.freedesktop.Hal --type=method_call \
    --print-reply /org/freedesktop/Hal/devices/computer \
    org.freedesktop.Hal.Device.SystemPowerManagement.Reboot int32:0

(this is probably more than necessary; works for me). I use this in a shell script. You don't need to run this from root, but you need to run it from inside an X session (f.e. in a terminal). You can find more on this topic at https://wiki.ubuntu.com/DebuggingGNOMEPowerManager

Solution 3

Occasionally, the usual (and preferred) reboot and shutdown commands don't work. I've seen this on a system with problems (which is why it needed rebooting).

You can trigger the "Magic SysRq" mechanism from the commandline:

echo b >/proc/sysrq-trigger

This is equivalent to alt-SysRq+b and will reboot the machine.

You may want to try "s" and "u" first to sync discs and unmount filesystems respectively.

Comments

[John T]

halt & poweroff actually turn the machine off completely, shutdown will only reboot the machine with the correct switches provided.

[Satanicpuppy]

Be careful with init. If the inittab has been changed, init 6 may be mapped to some other runlevel. I've seen a number of places that had the default runlevel after reboot set to single-user mode.

[stereoscott]

What is the advantage of this over sudo reboot?

[liori]

It will notify your session manager that you're about to reboot, and f.e. save your session status (apps opened). I'm not sure whether reboot or shutdown does that. Also, as I wrote in the answer, you don't need sudo or su (you need to be allowed to do that by session manager, but this is usually true in most desktop distros).

[Atcold]

What about if you're not sudo? When clicking, you don't have to be sudo...