The REPL prints the value of a variable that you type in. exit is a variable, and so the REPL prints its value. If you want to run it as a function, you can d

The REPL prints the value of a variable that you type in. exit is a variable, and so the REPL prints its value. If you want to run it as a function, you can do that, and indeed its string value is a message telling you to do that. $ python3 Python 3.9.2 (default, Feb 28 2021, 17:03:44) [GCC 10.2.1 20210110] on linux Type "help", "copyright", "credits" or "license" for more information. >>> exit Use exit() or Ctrl-D (i.e. EOF) to exit >>> exit.eof 'Ctrl-D (i.e. EOF)' >>> exit.name 'exit' >>> exit = 42 >>> exit 42 >>> exit() Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'int' object is not callable >>> I would have special-cased exit, though.