Official Blunder Discussion

This is probably a stupid question, but this is my first real box:
I managed to upload a p0wnyshell to the server and I figured out the user pwd, but I have no idea how to continue.

I can’t su because I don’t have a tty shell (and upgrading to a tty shell doesn’t work)
I have tried to create a reverse shell that connects to my Raspberry Pi via python, bash, PHP etc. but nothing happens. It seems like I can’t connect to anything.

And, as I said, stuff like sudo or su doesn’t work with my p0wny shell