Use this to download this category as MP3 with youtube-dl:
declare -a list=("https://www.youtube.com/user/epenser1" "https://www.youtube.com/channel/UCeR8BYZS7IHYjk_9Mh5JgkA" "https://www.youtube.com/channel/UCZeGNmKXVe6X_L32Dz1pxjQ/videos" "https://www.youtube.com/channel/UC5X4e8ScZI2AFd_vkjSoyoQ" "https://www.youtube.com/channel/UCKjDY4joMPcoRMmd-G1yz1Q" "https://www.youtube.com/user/notabenemovies/videos" "https://www.youtube.com/channel/UC4Jrte_YtwWfANKNyzse5iA/videos" "https://www.youtube.com/channel/UCNgqo37ZR6hkgvfCc-VLGtA" "https://www.youtube.com/channel/UCag73lWsCTMOmV7d_uG2ArA" "https://www.youtube.com/user/DrNozman/videos" "https://www.youtube.com/user/geoffreyspot" "https://www.youtube.com/channel/UCNk3CeLpCA0qIZsuzGl09cwa" "https://www.youtube.com/user/dirtybiology" "https://www.youtube.com/channel/UCNHFiyWgsnaSOsMtSoV_Q1A/" "https://www.youtube.com/channel/UC726J5A0LLFRxQ0SZqr2mYQ/videos" "https://www.youtube.com/channel/UCy3_8vRgz53j34pmUv1eV8Q/videos" "https://www.youtube.com/channel/UCv5MaoOOO9HervWWHZwwOjg/videos" "https://www.youtube.com/user/vulgarisation/videos" "https://www.youtube.com/channel/UC6nSFpj9HTCZ5t-N3Rm3-HA" "https://www.youtube.com/channel/UCGl2QLR344ry4Y20RV9dM3g" "https://www.youtube.com/channel/UC7DdEm33SyaTDtWYGO2CwdA" "https://www.youtube.com/channel/UC6107grRI4m0o2-emgoDnAA" "https://www.youtube.com/channel/UC8VkNBOwvsTlFjoSnNSMmxw")
for val in ${list[@]}; do
name=$(basename "$val")
if [ -e $name ]
then
continue
fi
mkdir $name
cd $name
youtube-dl -f mp3-128 $val
cd ..
done
