Launches ethminer when the display goes to sleep

launch-ethminer.service

# ~/.config/systemd/user/launch-ethminer.service
[Unit]
Description=Launches ethminer when the display goes to sleep.

[Service]
ExecStart=bash /home/pieter/v/launchminer.sh
KillMode=process

[Install]
WantedBy=multi-user.target

launch-ethminer.timer

# ~/.config/systemd/user/launch-ethminer.timer
# Enable the timer using the following command:
# $ systemctl --user enable launch-ethminer.timer
[Unit]
Description=Check every few seconds if the monitor went to sleep, so we can launch ethminer.

[Timer]
OnCalendar=*:*:0/2
Persistent=true     
AccuracySec=1sec

[Install]
WantedBy=timers.target

launchminer.sh

#!/bin/bash

# Get information about the X session.
XINFO=$(xset -q 2>/dev/null)
DATE=$(date)

if [ $? -eq 0 ]; then
  echo $XINFO | grep "Monitor is On" > /dev/null
  MONITOR_IS_ON=$((1 - $?))
else
  # X is not running.
  echo "$DATE X is not running" >> /home/pieter/v/launchminer.log
  MONITOR_IS_ON=0
fi

# If the monitor is switched on, retrieve all running miners and kill them.
if [ $MONITOR_IS_ON -eq 1 ]; then
  for PID in $(pidof ethminer); do
    echo "$DATE Kill miner $PID" >> /home/pieter/v/launchminer.log
    kill $PID
  done
# If the monitor is off, check if a miner is running. If not start one.
elif [[ ! $(pidof ethminer) ]]; then
  echo "$DATE Start mining" >> /home/pieter/v/launchminer.log
  ethminer -U -P stratum1+tcp://9d874d6a172efddcb302d1581213acae8a49c0d8.archsofia@eu1.ethermine.org:4444 &
fi