#!/bin/sh

get_feed()
{
	link="$(curl -L -s "$1" | pup 'link[title=RSS] attr{href}' 2>/dev/null)"
	[ "$link" ] && printf "%s\n" "$link" | tee /dev/stderr && exit
}

[ "$1" ] || exit 1

# url is channel
get_feed "$1"

part="$(echo "$1" | awk -F '/' '{print $NF}')"
# last part is channel id
get_feed "https://www.youtube.com/channel/$part"
# last part is channel tag
get_feed "https://www.youtube.com/$part"