[1]https://rg3.github.io/youtube-dl/ this is also a handy tool
   as well for downloading videos for archival purposes, just in
   case youtube goes down, does a wipe, whatever. Having been going
   through my writings through the decades online and putting them
   on [2]http://icopiedyou.com - the amount of things that were
   extremely difficult to retrieve were numerous.* There are a few
   things nearly impossible; I'm currently finding out if there are
   backup tapes of LISTSERVs from the early 1990s.* But as I've
   always been a hoarder by nature, the stuff that vanished from
   the web and ftp sites I had a lot of it on Floppies, which I
   transferred to zip disks at one point, then to an external hard
   drive when I acquired one of those and FINALLY was able to get
   it BACK up to the 'net. So I suppose, I do believe in The Cloud
   conceptually but not so much any individual corporate or
   University or private entity to maintain it for me. Rather, what
   I believe in is the Internet in general; redundancy, various
   forms of data expression.* If I have something in a PDF in one
   place, I should have a TeX formatted copy somewhere else. I
   should make it into a video with text-to-speech as well. Make a
   few animatedgifs with it; make them go viral so there's many
   copies. It's my own 'thing' though; not everybody is concerned
   with data loss; but knowing how people are (and all of these
   things are run by people), all it takes is one person to say,
   "Oh, that service?* Kill it. It's old now.* (aol, geocities,
   myspace, various blogging platforms through the decades, etc)

References

   Visible links
   1. https://rg3.github.io/youtube-dl/
   2. http://icopiedyou.com/