youtube-dl) and
returns the best quality mp4 version (in case you need to deal with a
device that doesn’t like modern video encodings/containers), with the
download time as the file’s modification time timestamp (useful if
you have a directory of downloaded videos and want to quickly see the
last N files you downloaded, rather than the files being sorted by
upload time).
Add to your ~/.bashrc or other shell configuration file as appropriate:
youtubemp4() {
youtube-dl -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/mp4' "$1"
touch "$(youtube-dl -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/mp4' --get-filename $1)"
}
Then call in the command-line, e.g. youtubemp4 https://www.youtube.com/watch?v=Gnnb6sjgk3A.