getch.py

def getch():
    is_windows = True
    try:
        import msvcrt
        
        def g_windows():
            return msvcrt.getch()
        
        impl = g_windows
    except ImportError:
        is_windows = False
        
        def g_unix():
            import sys, tty, termios
            fd = sys.stdin.fileno()
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(sys.stdin.fileno())
                ch = sys.stdin.read(1)
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
            return ch
        
        impl = g_unix
        
    return impl()

getch_apply.py

from getch import getch

# Supposing 'q' will end the program

ch = None
STOP = 'q'

while True:
    ch = getch()
    if ch.lower() == STOP:
        break
    
    # Execute your logic here...
    print ch