#!/bin/bash

#ls -al /dev/stdout
#ls  -al /proc/self/fd/1
#ls  -al /proc/$$/fd/1
#ls  -al /proc/$$/fd/

[[ -t 1 ]] && \
    echo 'STDOUT is attached to TTY'

[[ -p /dev/stdout ]] && \
    echo 'STDOUT is attached to a pipe'

[[ ! -t 1 && ! -p /dev/stdout ]] && \
    echo 'STDOUT is attached to a redirection'


echo "HHHEEELLLLOOO" | socat -u - UNIX-SENDTO:/proc/self/fd/1

#exec 3<>/proc/$$/fd/1
#echo "Hello world" >&3

# /dev/stdout -> /proc/29222/fd/1 -> socket:[2763848]