echo mycommand >/dev/tcp/127.0.0.1/1234

#!/bin/bash
echo "HTTP/1.0 200 OK
Content-Type: text/plain

running command" |
sed 's/$/r/'
if echo mycommand >/dev/tcp/127.0.0.1/1234
then echo OK
else echo fail
fi
date

socat tcp-listen:8001,reuseaddr,fork exec:/tmp/myscript

* Connected to localhost (127.0.0.1) port 8001 (#0)
> GET / HTTP/1.1
> Host: localhost:8001
> User-Agent: curl/7.43.0
> Accept: */*
>
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Content-Type: text/plain
<
running command
OK
Wed Aug 23 21:04:47 CEST 2017