Concept: Exit code

When a script is executed, it will return an exit code to the operating system when it finishes running. The exit code is a number that indicates whether the script ran successfully or encountered an error.

The exit code is typically 0 for a successful execution, and a non-zero value for an error.

In order to exit a script with a specific exit code, the exit function from the sys module must be used.

import sys
import random

if random.randint(0,1) == 0:
    print("Script ran successfully.")
    sys.exit(0)
else:
    print("Script encountered an error.")
    sys.exit(1)

An error code must be a positive integer no larger than 255. There are a few reserved exit code which should not be used outside their intended purpose. Any other code can be used to indicate an application specific error.

Exit code	Meaning
0	Success
1	General error
2	Misuse of shell builtins
126	Command invoked cannot execute
127	Command not found
128	Invalid argument to exit
130	Script terminated by Control-C