$ youtube-dl https://www.youtube.com/watch?v=rnMYZnY3uLA
[youtube] rnMYZnY3uLA: Downloading webpage
[youtube] rnMYZnY3uLA: Downloading video info webpage
[download] Destination: A Origem da Vida _ Nerdologia-rnMYZnY3uLA.mp4
[download] 100% of 32.11MiB in 00:12