Summary

One of the most important and time consuming tasks in scripting is building all of the conditional statements that we need to make the script usable and robust. There is an 80-20 rule that is often spoken of. This is where 20 percent of your time is spent in writing the main script and 80 percent of the time is spent to ensure all of the possible eventualities that are correctly handled in the script. This is what I refer to as the procedural integrity of the script, where we try to cover each scenario carefully and accurately.

We started by looking at a simple test with command-line lists. If the actions needed are simple, then these provide great functionality and are easily added. Where more complexity is required, we will add if statements.

Using the if statements, we can extend them as required using the else and elif keywords. Don't forget that elif keywords need their own conditions to evaluate.

Finally, we saw how we can use case where a single expression needs to be evaluated...