Reading and Resolving PowerShell Errors

Reading and Resolving PowerShell Errors - Part 1

One of the key skills that I teach in my PowerShell classes is to read the error messages. For the PowerShell programmer, error messages are a good thing. Error messages let us know that we are not about to release code that will make us look bad. I’ve noticed from years of teaching PowerShell that there are 3 major issues that people have with error messages:

1 – They do not read them.

2 – They do not understand them.

3 – They suppress them.

Let’s start with #3. PowerShell has a global variable called $ErrorActionPreference. It is set to Continue by default. What that means is if a non-terminating error occurs, show the error and continue. This is good because we know that an error has occurred. $ErrorActionPreference can also be set to SilentlyContinue. This means that if an error occurs, do not show anything or notify the user in any way. Just continue. This is bad because we do not know if there is a problem.

As for #1 and #2, they go hand-in-hand. I very often see my students getting an error message and then just start typing without reading it. This is despite the fact that I start my PowerShell classes with a syntax exercise in which we deliberately invoke errors so we know how to read them. For those that do read them, they are sometimes cryptic. This is very discouraging at times.

The purpose of this series to take a look at all the errors that pop up in just 1 week of one of my PowerShell classes and address them. I’ll be posting one a day.

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Jason Yoder, MCT

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