youtube-dl command

# To download a video or playlist:
youtube-dl '<https://www.youtube.com/watch?v=oHg5SJYRHA0>'

# To list all formats that a video or playlist is available in:
youtube-dl --list-formats '<https://www.youtube.com/watch?v=Mwa0_nE9H7A>'

# To download a video or playlist at a specific quality:
youtube-dl --format "<best[height<=480]>" '<https://www.youtube.com/watch?v=oHg5SJYRHA0>'

# To download the audio from a video and convert it to an MP3:
youtube-dl -x --audio-format <mp3> '<url>'

# To download the best quality audio and video and merge them:
youtube-dl -f bestvideo+bestaudio '<url>'

# To download video(s) as MP4 files with custom filenames:
youtube-dl --format <mp4> -o "<%(playlist_index)s-%(title)s by %(uploader)s on %(upload_date)s in %(playlist)s.%(ext)s>" '<url>'

# To download a particular language's subtitles along with the video:
youtube-dl --sub-lang <en> --write-sub '<https://www.youtube.com/watch?v=Mwa0_nE9H7A>'

# To download a playlist and extract MP3s from it:
youtube-dl -f "bestaudio" --continue --no-overwrites --ignore-errors --extract-audio --audio-format mp3 -o "%(title)s.%(ext)s" <url_to_playlist>

# ---

# To download a video in 720p MP4:
youtube-dl -f 22 example.com/watch?v=id

# To download a video in 720p MP4 or WebM or FLV:
youtube-dl -f 22/45/120

# To list all available formats of a video:
youtube-dl -F example.com/watch?v=id

# To download a video to /$uploader/$date/$title.$ext:
youtube-dl -o '%(uploader)s/%(date)s/%(title)s.%(ext)s' example.com/watch?v=id

# To download a video playlist starting from a certain video:
youtube-dl --playlist-start 5 example.com/watch?v=id&list=listid

# To simulate a download with youtube-dl:
youtube-dl -s example.com/watch?v=id

# For all video formats see
# http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs