Poor man's intercepting proxy

intercepting-proxy.sh

#!/usr/bin/env bash

# Thanks to https://blog.hawkhost.com/2009/12/12/using-netcat-as-an-intercepting-proxy/

server=${1:-localhost}
localport=${2:-8080}
remoteport=${3:-$localport}

pipe=intercepting-proxy.pipe

# shellcheck disable=SC2094
rm -f "$pipe" &&
    mkfifo "$pipe" &&
    echo "listening for localhost:${localport} to proxy to ${server}:${remoteport}..." &&
    nc -k -l -p "$localport" < "$pipe" | tee proxy-requests.log | nc "$server" "$remoteport" | tee "$pipe" proxy-responses.log