Concat mp4 file with ffmpeg

**Concatenated’’ video files (e.g. *.mp4) specified in *.txt file ‘‘created’’ on the file

Example: If you got *.mp4 files starting from: 1 to 46

file sound.mp4
file 46-Con-xyz-rendered.mp4
file sound.mp4

for i in {1..46}; do
    file=$(echo ${i}-*-rendered.mp4);
    touch ${file};
    echo -e "file sound.mp4\nfile ${file}\nfile sound.mp4" > ${file%.mp4}.txt;
    ffmpeg -f concat -safe 0 -i ${file%.mp4}.txt -c copy ${file%.mp4}-final.mp4;
done