If I run my code it works well but I want it to show me a different output when I input start for the second time in the terminal

Question

At run time

The code behaves in an unusual way .when I say start it shows me car started ready to go But when I say start again it till shows the same output I want the code to show me car already started when I say start for the second time

command = ""
while command != "quit":
    unit = input("> ").lower()
    if unit == "start":
        print ("car started ... ready to go")
    elif unit == "stop":
        print("car stopped")
    elif unit == "help":
        print("""
start - start the car
stop - stop the car
quit - exit
        """)
    elif unit == "quit":
        break
    else:
        print("sorry I don't understand") 

Answer 1

You will need some state that stores in which state the car currently is in order to make this happen. In your case you could simply use a flag car_running which you set accordingly.

car_running = False

command = ""
while command != "quit":
    unit = input("> ").lower()
    if unit == "start":
        if car_running:
            print("car has already been started")
        else:
            print("car started ... ready to go")
            car_running = True
    elif unit == "stop":
        if car_running:
            print("car stopped")
            car_running = False
        else:
            print("car is not running")
    elif unit == "help":
        print(""" start - start the car stop - stop the car quit - exit """)
    elif unit == "quit":
        break
    else:
        print("sorry I don't understand")

If you have multiple states are car can be in you could use an enum.

What your building is essentially a finite-state machine.