Mirror android in ubuntu (linux)

1. open terminal hit enter below command
2. sudo apt-get install android-tools-adb
3. sudo apt-get install ffmpeg
4. go to android device open setting developer option and allow usb debugging and connect android to ubuntu using usb cable 
5. open terminal enter -

         adb shell screenrecord --output-format=h264 - | ffplay -
    6. Now wait for sometime 10sec screen will be open successfully