[lunatic]

I hate to say it, lunatic, but that script seems like an unnecessarily and overly complicated way of extracting audio from a YouTube video.  There's no need to use ffmpeg to convert to wav and then lame to encode to mp3; ffmpeg can create the mp3 directly.  There's no need to manually call ffmpeg; both youtube-dl and yt-dlp have built in options for post-processing downloads.  YouTube even offers downloads of the audio and video already separated.  And there's no need to use those shell expansions to get the title; there are formatting options for that.  

I did not know that. That is great indeed. This little shell script may be from a time before these features existed.