As a style hint, also consider breaking the code into functions, instead of using triple-quoted strings (these are generally not docstrings!) to label "sections" of the code. (Even where you don't extract a separate function, that's what comments are for; the otherwise-blank lines with a # are also strange.)

Using a separate shell process for the camera control is inconvenient, and as written isn't going to work on others' machines (in the Python code, you've hard-coded an absolute path to the script in your home directory). I guess this is to avoid thinking about unbuffered I/O in Python; it's really not hard to do that on Linux (there's a curses binding in the standard library; or you can do just the "switch to raw mode" part using https://docs.python.org/3/library/termios.html and call sys.stdin.read (or perhaps sys.stdin.buffer.read) directly.)