#!/usr/bin/env bash
set -xe

echo "hello" | nc -lp 0 | grep -q "there" && echo "Got there" &
PID=$(ps | grep nc | head -n 1| awk '{print $1}')
inode=$(ls -lAF /proc/$PID/fd | grep socket | sed -e 's/.*\[//g' -e 's/\].*//g')
hex=$(grep $inode /proc/net/tcp | awk '{print $2}' | sed 's/.*://g')
port=$(printf '%d' "0x$hex")
exec 3<>/dev/tcp/127.0.0.1/$port
echo "there" >&3
grep -q "hello" <&3 && echo "Got hello"