====== sys ======

===== sys.exit() =====

Always use ''sys.exit()'' to exit in production code. Built-in's like ''quit'' or ''exit'' can be omitted in some envs.

===== os._exit() =====

**os._exit(n)** Exit the process with status n, without calling cleanup handlers, flushing stdio buffers, etc.

Note: The standard way to exit is sys.exit(n). _exit() should normally only be used in the child process after a fork(). 

==== exit codes ====

[[https://docs.python.org/3/library/os.html#os.EX_OK|os.EX_OK]]