merge video files from folders recursively with ffmpeg

merge.sh

#!/usr/bin/env bash

#set -o xtrace   # output every line which gets executed
set -o nounset  # fail if an unset variable is used
set -o errexit  # fail if a command exits with non-zero
set -o pipefail # fail if a command in a pipe fails


recurse() {
 for i in "$1"/*;do
    if [ -d "$i" ];then
#        echo "dir: $i"

                rm -f "$i"/merge.txt
                find "$i" -maxdepth 1 -type f -name "*-cd*.avi" ! -name ".*"  -execdir echo file \'{}\' >> "$i"/merge.txt \;

                if [ -s "$i"/merge.txt ]; then
                        echo "$i"
                        ffmpeg -y -f concat -safe 0 -fflags +genpts -i "$i"/merge.txt -c copy "$i"/"$(basename "$i").mkv"
                else
                        rm "$i/merge.txt"
                fi
        recurse "$i"
#    elif [ -f "$i" ]; then
#        echo "file: $i"
    fi
 done
}

recurse "$1"