Use this to download this category as MP3 with youtube-dl:
declare -a list=("https://www.youtube.com/channel/UCVcg0ify3ghouZVCYJMpDSg" "https://www.youtube.com/channel/UCywlxeGsmbLMdt2XcqNrg9g" "https://www.youtube.com/channel/UCMrvLMUITAImCHMOhX88PYQ/videos" "https://www.youtube.com/channel/UCoeJKtPJLoIBqWq4o8TDLpA/videos" "https://www.youtube.com/user/photoshoptrainingch/videos" "https://www.youtube.com/channel/UC6PIKnoGw7rJnND6_jdoo5w/videos")
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
