Merge two video with ffmpeg

I need, Merge two video with ffmpeg code.

Please share some working coding here.

I'm trying with this code. Result faild!

Sohel, What about logs?

Can you give me a working code. I'm tested many code but all are not worked..

Need to know reason of the problem. I could help, if you give the command, which you ran, and output data of this command.

Give me a merge two video command here.

Sohel, Are you kidding me? >=|