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So let's first understand errors and exceptions.

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So let's understand the basic terminology. So the first one is an exception.

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This is like an event.

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It gets created when a normal error handling can't deal with the issue.

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The second one is throw and catch. So this happens when an

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exception occurs, and so you say that an exception is

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thrown. To handle a thrown exception,

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you have to catch that exception to do something with it.

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Now, along with that is the call stack.

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The call stack is the list of functions that were called by each

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other that led up to and after the exception.

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We then have what's called terminating and non‑terminating errors.

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This is an exception that's generally a terminating error.

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A thrown exception can either be caught or it terminates the current execution.

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And then we have what's called swallowing an exception.

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So this is when you catch an error and it just literally disappears.

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So it doesn't really serve any purpose,

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but you're just capturing it and ignoring it.

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So what are the differences between errors and exceptions?

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Well, an error is returned as a PowerShell object,

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and so it provides the terminating and also non‑terminating errors,

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whereas exceptions are created when the normal error

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handling cannot handle the issue.

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Exceptions are typically non‑terminating errors, effectively.

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So what's the difference between a terminating and a non‑terminating? Well,

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a terminating one, the error is generated by the script,

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function, or commands.

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It will officially stop or halt the execution going forward. Whereas a

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non‑terminating one, this tends to be generated by internal commands.

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It's normally automatically handled so the error doesn't

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terminate the execution of the pipeline.

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So what are the error handling approaches that we can use?

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Well, the first one is to throw the exception.

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So as soon as the exception comes,

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we capture it, and we just throw the exception,

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which effectively will potentially break and stop the execution.

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We can do what's called Write‑Error,

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so we effectively write a message out and say we found

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an error and write the message out.

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We could also use what's called ‑ErrorAction,

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which is an operator that will then determine what we can do.

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There's some predetermined values for the error action.

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We could also Try/Catch, the idea being that as it

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executes it will try, and if it errors, then we automatically catch that error.

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We could then also do what's called Try and Finally,

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which is a combination of the Try and the Catch with a default

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of Finally action that comes out of there.

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And then, of course, we can do Try/Catch/Finally,

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So it's really up to you the different options that we've

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got, but we'll talk about some of these now.

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So first off, let's look at how we generate and handle errors.

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So I'm going to create a function here called Function New‑Error,

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and then we're going to use the word Throw.

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Now what Throw will do is cause the error to be generated.

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So if I say Write‑Error ‑Message "This is an Error" ‑ErrorAction Stop,

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this is almost the same as using the New‑Error function using the Throw

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word. So Write‑Error will write an error message,

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but the ErrorAction is the key to this.

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It will force it to stop. So two different approaches.

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You can see that I'm throwing an error or I'm throwing an

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error and then stopping it from carrying on.

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Now,

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if we look at how we generate and handle an error, if I go

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through this same process again and say New‑Error,

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I've got a number, it starts at 0, you can see that I'm

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iterating through, and say, okay, error starts at,

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you know, it starts at number 1, is it greater than 10, append,

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and keep going, you can see I've got Write‑Host, the current

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number is whatever the number is,

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and then I have an arbitrary line in there that says Throw "This is an

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Error". When I execute that, it will throw that error irrelevant of where

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that is. Now, if I use that same syntax, that same command and say New‑Error

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with an ErrorAction, when the throw occurs,

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it will stop the function from executing.

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So you just need to be aware that there's different ways of handling it,

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and you may need the syntax to continue executing, let you know about the error,

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or you may need to throw the error and stop. Now the

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ErrorAction parameter has specific values.

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The first one is Continue. So this will log the error, display

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it to you, and then continue processing.

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The next would be to Stop. That will log the error,

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display the error, and then terminate. SilentlyContinue

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is one that I often find people using.

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I would advise not using that one unless you know for sure

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that the error isn't anything to worry about.

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But this will log an error, doesn't display anything, and just carries,

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which can have an impact on the rest of the syntax.

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And then, of course, you've got Ignore.

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It doesn't log an error, it doesn't display anything,

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and it just continues processing.

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So choose wisely on those last two, SilentlyContinue and Ignore.

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I wouldn't advise you use those all the time.

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I would rather you went through, and if you're using the ErrorAction, that you would use Continue and Stop as you need them.