For the record, if you only use youtube-dl for the purposes of downloading audio (like me), then you can keep a config file in $HOME/.config/youtube-dl/config with default arguments so you don't have to look them up each time. For example, here's a sample from my config:

    # extract audio only
    -x
    # stick to mp3
    --audio-format mp3
    # get rid of the annoying URL stuff at the end
    -o "%(title)s.%(ext)s"