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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