理解Python中sys.exit()||os._exit()||quit()||exit()

• Preface

  The functions quit(), exit(), sys.exit() and os._exit() have almost same functionality as they raise SystemExit exception by which the Python interpreter exits and no stack traceback is printed.

  When we run a program in Python, we simply execute all the code in file, from top to bottom. Scripts normally exit when the interpreter reaches the end of the file, but we may also call for the program to exit explicitly with the built-in exit functions.

• quit()

  It works only if the site module is imported so it should not be used in production code.

  Production code means the code is being used by the intended audience in a real-world situation. This function should only be used in the interpreter.

  It raises the SystemExit exception behind the scence.

• exit()

  exit() is defined