What happens when you concatenate 2 or more MultiChannel avi files

[GTA Driver]

Some of the time I have two or more MP4 files I would like to combine to one file. Instead of using an editor , I would like to do it at the shell level in Linux.

Ie

$ cat file1.mp4 file2.mp4 file3.mp4 > all.mp4

it would be nice if there was screen tag, will use code instead.


When I view all.mp4, it shows only file1.mp4, not the other files.
I read somewhere that other formats, such as mpg permit concatenation.

Apparently, according to http://stackoverflow.com/questions/7333232/concatenate-two-mp4-files-using-ffmpeg you can't concatenate mp4 files with cat. You need to use ffmpeg or other

So what happens when you concatenate multi channel avi files

$ cat file1.avi file2.avi file3.avi > all.avi

or

$ mkdir allfiles
$ cat *.avi  > allfiles/all.avi

Questions

1. Does it show all files
2. Do you see front and rear channel