Sample downloading bash script (yt-dlp)

sampdl.sh

#!/usr/bin/bash 
sample_dir="~/music/sampledl"
yt_dlp_path="/usr/local/bin/yt-dlp"
audio_format="mp3"

regex='(https?|ftp|file)://[-[:alnum:]\+&@#/%?=~_|!:,.;]*[-[:alnum:]\+&@#/%=~_|]'
if [ -n "$1" ]; then 
    URL="$1" 
else
    URL=$(xsel -o) 
    if ! [[ $URL =~ $regex ]]; then
        echo "\"$URL\" <-- this is not a valid URL in your clipboard"
        exit
    fi 
fi
yt-dlp -x --audio-format mp3 --audio-quality 0 -o "$sample_dir/%(title)s.%(ext)s" --restrict-filenames $URL 

echo "[DEBUG] updating yt-dlp"
echo "[DEBUG] https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp"  
curl -s -L https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -o $yt_dlp_path && chmod a+rx $yt_dlp_path