FFmpeg Video Editing Command to Merge audio and video

In this tutorial i have given description and demo of video editing commands is about creating video with solid background color with desired length video.

Used command in this Tutorial [join multiple mp4 video files into one video]

ffmpeg -f concat -i join.txt -c copy joined.mp4

[adding audio file with mp4]

ffmpeg -i joined.mp4 -i xyz.mp3 -shortest output.mp4