216 – Setting the exit code

For scripts, command line interfaces, and other code that is typically run in the terminal, use sys.exit to set the exit code to an appropriate value.

An exit code of 0 means the program terminated successfully:

import sys

# ...

sys.exit(0)

Any other integer value (from 1 to 255) will tell the terminal that the program ended with an error:

import sys

# ...

sys.exit(42)  # Error code 42.

It is up to your program to assign meaning to each error code, in case it’s relevant.

A program that terminates with an exception automatically gets the error code 1:

# myscript.py

1 / 0

The file myscript.py has the single line 1 / 0, which raises an exception. Running it in the terminal, you see the exception:

$ python myscript.py
ZeroDivisionError: division by zero
$ echo $?
1

The command echo $? prints the exit code of the previous command, so the result of 1 shows that Python terminated with the exit code 1.