How to cancel shutdown on Linux?

Question

I'm familiar with and use shutdown in Linux, and typically just do

> shutdown -h now

But is there a way to stop shutdown from happening, say if I aim to shutdown 10 minutes from now and then in 5 minutes' time I discover I really don't want to shut down?

Answer 1

You can use  ps  to find the shutdown process and abort it, for example with ps|grep shutdown.

Alternate and less eyeball-intensive versions of this:

pkill shutdown
killall shutdown
kill `cat /var/run/shutdown.pid`

Answer 2

shutdown -c  is "cancel shutdown" on reasonably recent shutdowns.

The syntax also supports shutdown -c <message> for announcement purposes, so that's handy if other people use the machine.

Answer 3

From shutdown's man page on BSD systems:

A scheduled shutdown can be canceled by killing the shutdown process (a SIGTERM should suffice).

Answer 4

If you're a second late on the draw for shutdown -c, and already root on the console, a very fast # init 5 will cancel a shutdown after init changes runlevel.

NOTE: This answer is mostly obsolete now. init 5 isn't very useful on systemd, which, sadly, most systems now use.