Linux: Create a Shell Script to Watch Services

# create a script to watch services (notice the regex escape for special chars)
sudo cat << EOF > /usr/local/sbin/watchservice
#!/bin/bash
service=\$@
/bin/systemctl -q is-active "\$service.service"
status=$?
if [ "\$status" == 0 ]; then
    echo "OK"
else
    /bin/systemctl start "\$service.service"
fi
EOF

# Mark the file with executable permissions
sudo chmod +x /usr/local/sbin/watchservice

# Create a new entry in cron
sudo crontab -e

# Ensure that services are running
* * * * * /usr/local/sbin/watchservice pihole-FTL > /dev/null