Makes a playlist of all audio files in directory and all descendant directories. It detects audio files just by some well known file name extensions.

mkplaylist.sh

#!/bin/sh

dir="$1"
playlist="$2"

if [ "$playlist" = "" ]; then
	playlist=playlist.m3u
fi

find "`readlink -f "$dir"`" -type f -and \( -iname '*.mp3' -or -iname '*.ogg' -or -iname '*.wav' -or -iname '*.flac' -or -iname '*.m4a' -or -iname '*.aac' -or -iname '*.wma' -or -iname '*.opus' \) > "$playlist"