Ubuntu – Prevent PC from shutting down on Power button

The number of processes should not be different. You have to remember when counting the pids to include the script itself and the subprocess created.

I created the following that should work for your requirements. You should alter the timeout depending on how quickly you want the multiple button presses.

#!/bin/sh
# /etc/acpi/powerbtn.sh
# Initiates a shutdown when the power putton has been
# pressed.

timeout=0.8
pid_count=$(pidof -x powerbtn.sh | wc -w)

( if [ $pid_count -eq 4 ]; then
        sleep $timeout
        /etc/acpi/sleep.sh
    else
        sleep $timeout
        pid_count_now=$(pidof -x powerbtn.sh | wc -w)
        if [ $pid_count_now -eq 2 ] && [ $pid_count -eq 2 ]; then
            poweroff
        fi
        exit
    fi
) &

Check your /etc/systemd/logind.conf file. It should look like this:

[Login]
#NAutoVTs=6
#ReserveVT=6
#KillUserProcesses=no
#KillOnlyUsers=
#KillExcludeUsers=root
#Controllers=
#ResetControllers=cpu
#InhibitDelayMaxSec=5
#HandlePowerKey=poweroff
#HandleSuspendKey=suspend
#HandleHibernateKey=hibernate
#HandleLidSwitch=suspend
#PowerKeyIgnoreInhibited=no
#SuspendKeyIgnoreInhibited=no
#HibernateKeyIgnoreInhibited=no
#LidSwitchIgnoreInhibited=yes
#IdleAction=ignore
#IdleActionSec=30min

Uncomment the line that says #HandlePowerKey=poweroff and change the value to ignore.

Then restart the logind with the command: sudo restart systemd-logind or reboot your computer.

EDIT: how to create a new acpi handler Create a new file in /etc/acpi/events/. The content of the file should be:

event=<acpi_event_code>
action=<script_to_call>

where <acpi_event_code> is the code you get using the acpi_listen tool and <script_to_call> is the full path to the script you wish to call when that event happens.

They must have changed something in 13.10 because it seems that I have too few files in my /etc/accpi/events folder compared to the 13.04.