How to join MP4 and M4A to a movie using VLC's commandline

[Skeeve]

I already asked this over at Stackoverflow, but no help there… (I would link to the question, but I don't know whether I'm allowed to)

I found a way how to add an m4a audio file to an mp4 video file using VLC.

I use the extended file open(?) (Shift-Cmd-O on my Mac) and select the Video file to play. Then I saelect the audio file to play synchronuously.

Finally I use Stream output as MPEG4 to my destination file.

How can I achieve this using commandline?

My goal is to automate this process via a bash script, so any help would be really appreciated.