I had a bunch of MP4 files I wanted to merge into a single file. FFMpeg came to the rescue, but it had a bit of a quirk I needed to figure out. Thanks to this site for the help.

First, create a list of files you wish to merge. In this example I want every file with a specific file pattern beginning with 2019-05-02. I take that output and run sed against it to add “file ‘” to the begging and a closing ” ‘ ” at the end. The end result is a nice list of files for ffmpeg to ingest.

ls 2019-05-02* | sed "s/^/file '/g; s/$/'/g" > filelist.txt

With our shiny new list we can now tell ffmpeg to use it to concatenate to a single file:

ffmpeg -f concat -safe 0 -i filelist.txt -c copy OUTPUT_FILENAME.mp4