Monitor Remote Services

Notify when service goes down:

while `nc -z -w3 <HOST> <PORT> > /dev/null`; do sleep 1; done; echo "[-] Service is dead"; echo -e "\x07"

Notify when service goes up:

while (true); do nc -z -w3 <HOST> <PORT> > /dev/null && echo "[+] Service is alive" && echo -e "\x07" && break; sleep 1; done