radiosoulwax->m4a

process.bash

#!/bin/bash

videos=(http://vimeo.com/93039571
        http://vimeo.com/26149143
        http://vimeo.com/26149014
        http://vimeo.com/25861552
        http://vimeo.com/26148917
        http://vimeo.com/26113014
        http://vimeo.com/26048972
        http://vimeo.com/26112742)

youtube-dl "${videos[@]}"

for video in *.mp4; do
    m4a="${video%-*}.m4a"

    [[ ! -f "$m4a" ]] && \
        ffmpeg -i "$video" -map a:0 -c copy "$m4a"
done