-i - ignore errors
-c - continue
-t - use video title as file name
--extract-audio - extract audio track
--audio-format mp3 - convert to mp3
--audio-quality 0 - the best audio quality
--yes-playlist - affirm that url points to a playlist
YT_URL - video url from youtube
# Download single entry
youtube-dl -i --extract-audio --audio-format mp3 --audio-quality 0 YT_URL
# Download playlist
youtube-dl -ict --yes-playlist --extract-audio --audio-format mp3 --audio-quality 0 https://www.youtube.com/playlist?list=UUCvVpbYRgYjMN7mG7qQN0Pg
# Download playlist, --download-archive downloaded.txt add successfully downloaded files into downloaded.txt
youtube-dl --download-archive downloaded.txt --no-overwrites -ict --yes-playlist --extract-audio --audio-format mp3 --audio-quality 0 --socket-timeout 5 https://www.youtube.com/playlist?list=UUCvVpbYRgYjMN7mG7qQN0Pg
# Retry until success, no -i option
while ! youtube-dl --download-archive downloaded.txt --no-overwrites -ct --yes-playlist --extract-audio --audio-format mp3 --audio-quality 0 --socket-timeout 5 <YT_PlayList_URL>; do echo DISCONNECTED; sleep 5; done