I hear that youtube-dl is a great program. It will also help you download content from other sites such as slideshare and vimeo etc: https://ytdl-org.github.io/youtube-dl/supportedsites.html I've also heard that sites like youtube aren't fond of tools like youtube-dl, so they change the metadata associated with their content on a regular basis to thwart such tools. As a result, the youtube-dl installed with your distro packaging is likely out of date, you'd be better off to install it using one of the python packaging/installing tools directly (and keep it up-to-date that way). As a result, I hear there are sometimes small gaps between youtube changing their metadata, and youtube-dl catching up. Also, youtube does detect downloads via youtube-dl, and will cut you off (or more specifically, will cut off your IP) if you use it (in their opinion) too much (search for: "youtube-dl unauthorized 403"). So you'd be wise to throttle your usage of such a tool. ...or so i've heard...
