Restart LinuxGSM based Left 4 Dead 2 server that is both empty and not running the default map.

check.sh

#!/bin/bash
#depends on gamedig being installed globally
#place in /home/l4d2server (can probably work with other LGSM servers with minor modifications).
gameserver="l4d2server"
game="left4dead2"
config_path="./lgsm/config-lgsm/$gameserver/"
server="1.1.1.1" #change to server ip
for i in $(find . -maxdepth 1 -name "$gameserver*" | sed 's|^./||'); do
	defaultmap=$(grep -P '^(?=[\s]*+[^#])[^#]*(defaultmap)' $config_path$i.cfg | awk -F\" '{print $2}')
  	port=$(grep -P '^(?=[\s]*+[^#])[^#]*(port)' $config_path$i.cfg | grep -v 'client' | awk -F\" '{print $2}')
	currentmap=$(gamedig --type $game $server:$port | jq '.map' | awk -F\" '{print $2}')
	players=$(gamedig --type $game $server:$port | jq '.players | length')
	if [[ "$currentmap" != "$defaultmap" && $players -eq 0 ]]; then
		./$i restart
	fi
done

Next steps:

1. npm install gamedig -g
2. sudo apt install jq
3. crontab -e
4. */5 * * * * /home/l4d2server/check.sh > /dev/null 2>&1

Will work with any LinuxGSM server that has gamedig support. Just change the gameserver to your gameserver, game to the gamedig game type, and server to either localhost or your server ip.