no other user except "pi" possible.

[thomasgoehler]

If you install your Raspberry Pi with another user than user "pi" the server will not be installed in the directory /home/pi/mcserver. Can you modify your sh script to accept any user?

This is actually relatively simple to implement in your sh script. Instead of the user "pi" you can insert "$USER" in the places in your script. This way the current user will be used in your script.