Specifically, the ones that happen when you try to run your Python scripts and they don’t go as planned. But no need to get all worked up, because in this tutorial, we’ll be discussing how to understand common exit codes and what they mean for your code.

Before anything else, what an exit code is. In programming terms, it’s a numerical value that indicates whether the program ran successfully or if there were any issues during execution. These values are typically returned by the operating system to the shell or command prompt when you run a script.

Now, for those of us who aren’t math whizzes, let’s break down some common exit codes and what they mean:

– 0 (zero): This is the most popular exit code in Python land! It means that your program ran successfully without any errors or issues. Congratulations, you did it!

– 1: If your script returns a value of 1, it usually indicates that there was an error during execution. However, this isn’t always the case sometimes it can mean that something unexpected happened but wasn’t necessarily a critical issue. For example, if you accidentally deleted a line in your code and forgot to add it back in, running the script would return a value of 1 because there was an error with syntax.

– 2: This exit code is typically used when there are issues with system resources or permissions. If your program requires access to certain files or directories that you don’t have permission for, it will likely return a value of 2. Similarly, if your script runs out of memory or other resources, this can also result in an exit code of 2.

– 3: This is another common error code that indicates there was some sort of issue with the input data provided to your program. For example, if you’re trying to convert a string into an integer but it contains non-numeric characters (like “1a”), this can result in an exit code of 3.

Now, how we can use these exit codes to our advantage! One way is by checking the value returned by your script and using conditional statements to handle errors appropriately. For example:

# Import the subprocess module to run external commands
import subprocess

# Run the 'ls -l' command and store the result in the 'result' variable
result = subprocess.run(['ls', '-l'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

# Check the return code of the command to see if it was successful
if result.returncode != 0:
    # If the return code is not 0, an error occurred while running the command
    print("An error occurred while running the command.")
else:
    # If the return code is 0, the command was successful
    # Decode the output data from bytes to string and split it into lines
    for line in result.stdout.decode().splitlines():
        # Print each line of the output
        print(line)

In this example, we’re using the `subprocess` module to run a command and capture its output. If there are any errors during execution (i.e., if the exit code is not 0), we’ll print an error message instead of trying to process the data. This can be especially useful for scripts that need to interact with external programs or systems, as it allows us to handle unexpected issues gracefully and provide helpful feedback to users.

While they may not seem like much at first glance, understanding how these values work can help you troubleshoot errors more effectively and improve the overall reliability of your code.