#!/bin/bash
PORT=12345

# For every input line
while IFS= read -r payload; do
    # For every character
    for (( i=0; i<${#payload}+1; i+=1 )); do
        char="${payload:$i:1}"
        if [[ "$char" == "1" ]]; then
            timeout 1 nc -lp "$PORT" >/dev/null
        else
            sleep 1
        fi
    done
done