Is there a free program to join and cut AVI movie files? I have a camera and it creates an AVI file every 10 minutes when recording video. I would like to join files from the camera and sometime trim part of the video. I don't want re-encode the files if possible.

Is there a free program that will let me concatenate a split AVI files?
You can also use the concat demuxer with ffmpeg:

ffmpeg -f concat -i &lt;(for f in $PWD/*.avi;do echo "file '$f'";done) -c copy output.avi


-c copy disables re-encoding the streams.

You can install ffmpeg with brew install ffmpeg after installing Homebrew.

See https://trac.ffmpeg.org/wiki/How%20to%20concatenate%20%28join,%20merge%29%20media%20files for more information.