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Next, we need to look at a concept that trips up a lot of

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PowerShell beginners, and that is this idea of variable

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expansion. Here is a typical string usage.

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I'm creating a variable $name and giving it a value of Jeff.

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And I want to use this variable to construct a string or a

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message to display to the user.

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For example,

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I might want to show, Hello, my name is, and then fill in the

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blank with $name and put in whatever $name is.

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In this case, it says Jeff.

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Now I'm showing you this in the console. Although this is

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something you probably typically will do more when you

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get to PowerShell scripting, the concepts still apply.

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So what should happen and what you're expecting to happen

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is that you get a result like this.

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Perfect.

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That's what I want.

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This works great for simple values where $name is

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just a simple string like Jeff.

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Now this is where it gets a little tricky.

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I've got the same variable, $name = "Jeff".

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Now I have my string, 'Hello,

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my name is $name.', but notice the quotes. I'm using single quotes here as

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opposed to double quotes. When you use a single quote, PowerShell treats that

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variable as an explicit or literal string that you want to display to the

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screen. So variables are not expanded within single quotes. They're only

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expanded or replaced with double quotes.

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This is something that trips up a lot of people. And this takes it even further.

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If you thought the single/double quote was kind of confusing,

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let's say I have a variable, a more complex variable like a

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service object. And in this case, my service object,

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I can see that there are two properties,

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name and status. And I want to create a string that says to the user. hey,

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I basically wanted to say the BITS service is stopped.

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But if you run that command, even though I'm using double quotes,

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which should tell PowerShell, hey,

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expand or replace the variables, this will fail.

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What you're going to need to do is to use something called a subexpression,

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and that's something that I'm going to get to in a moment. In fact, let's do it right now.