How to combine MP4 files on the Debian linux
If you are looking to combine MP4 files from the command line here is the easiest solution. First you need to use the following command to install the program.
sudo apt-get install gpac
Once installed you will be able to run the following command to join the files.
MP4Box -cat mp4_file_part_1.mp4 -cat mp4_file_part_2.mp4 -new joined_file.mp4
You should now be able to combine MP4 files from the command line, and pretty quick at that.