Problem:

You have a 2 or more videos and need to merge into one. You don’t need to re-encode the video.

Solution 1: Using ffmpeg in bash

Step 1. Create a list file with their paths

Example, create the file list.txt:

file 'uno.mp4'
file 'dos.mp4'

or generate the file manually:

MYLIST=list.txt
find *.mp4 -maxdepth 1 ! -name $MYLIST -type f -print0 | xargs -0 -I {} echo "file '{}'" >> $MYLIST

Step 2. Merge the video files

ffmpeg -f concat -safe 0 -i list.txt -c copy output.mp4

Source:

https://stackoverflow.com/questions/7333232/how-to-concatenate-two-mp4-files-using-ffmpeg
https://trac.ffmpeg.org/wiki/Concatenate