In trying to debug a project, I want to verify that my rpi is recognizing the connection of the jumper cable to the GPIO pin. I can see with my eyes that it is connected. However, I want to rule out any connection problems that may not be able to be seen. (Please assume for purposes here that my suspicion of the connection is reasonable.)
Is there a command that will tell whether or not something is connected to a certain pin and if that something is, in some basic sense, functioning correctly?
If not, is there any other simple way (python one-liner, etc.) to verify that a connection has been made properly?