#/bin/bash
ls *.mp4 > file.txt
for f in *.mp4; do echo "file '$f'" >> mylist.txt; done
ffmpeg -f concat -i mylist.txt -c copy output.mp4

#/bin/bash
ls *.MOV > file.txt
for f in *.MOV; do echo "file '$f'" >> mylist.txt; done
ffmpeg -f concat -i mylist.txt -c copy output.MOV