check multiple connections and write to a log

conncheck.sh

#!/bin/bash
# make sure to install fping first. 
# and run this in a screen env. or make sure it's detachable, I was lazy.
# 
adddate() {
    while IFS= read -r line; do
        echo "$(date +%Y-%m-%d" "%H:%M:%S) $line"
    done
}
while true; do fping <ip-1> <ip-2> <ip-n> | adddate | tee -a output.log;done