#!/bin/zsh

usage()
{
  echo "$0 <yt link> <mp3 file>"
  exit 1
}

if [ -z $1 ] || [ -z $2 ]; then usage; fi

TMP_FN=/tmp/youtube-dl-$RANDOM
while [ -a $TMP_FN ]; do
  TMP_FN=/tmp/youtube-dl-$RANDOM
done
echo $TMP_FN

youtube-dl --output=$TMP_FN --format=18 "$1"
ffmpeg -i $TMP_FN -acodec libmp3lame -ac 2 -ab 128k -vn -y "$2"
rm $TMP_FN