I use Raspberry's GPIO from Bash because it only require 6 lines for what I need: a button and a LED.
I can read an input, and write an output. Very simple.
But I can not find how to active/desactivate the internal pull-up or pull-down resistors.
I searched into the Python library, and found the place where the magic happens. But I'm unable to understand what is done.
Same thing with the wiringPi library (the C code is very similar).
--> what are the low level steps to control the internal pull-up resistors?
UPDATE: I already see an answer with "a library is the only way", and I see similar answers everywhere. But if it can be done inside a library, it probably can be done with Bash (without having to install/compile/whatever a library).