Idle mining with GPU https://www.reddit.com/r/linux_gaming/comments/mqilcq/mine_with_your_idle_gpu/

trex_manager.sh

#!/bin/bash
# This script checks for the presence of a process using high GPU memory other than its own etherum miner, and terminates the miner. If it does not find such a process, it starts the miner.

MAX_MEMORY=500
MINER_NAME=t-rex
MINER_PATH="/home/trex/t-rex -a ethash -o stratum+tcp://asia1.ethermine.org:4444 -u WALLET_ADDRESS -w hashcat1"

# Get data on GPU processes
gpuprocs=$(nvidia-smi | head -n -1 | sed -n -e '19,999999 p' | awk 'BEGIN{ OFS = ";"; FS="   *"}{split($0,a);print a[5],a[6],(a[8]+0)}')

for proc in $gpuprocs
do
        memory=$(echo $proc | awk -F";" '{print $3}')
	pid=$(echo $proc | awk -F";" '{print $1}')
	if [ $memory -gt $MAX_MEMORY ] && [ $(ps -p $pid -o comm=) != $MINER_NAME ]; then
		echo "Found priority process, killing miner..."
		tpids=$(pidof $MINER_NAME)
		for tpid in $tpids
		do
			echo "Killing $tpid."
			kill $tpid
		done
		echo "Done here, exiting"
		exit 0
	fi
done

pidof $MINER_NAME >/dev/null && echo "Miner is already running" || /usr/sbin/runuser -l trex -c "screen -dmS trex $MINER_PATH"