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Now that we've seen some examples of early filtering with parameters,

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let's take a look at Where object.

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Once again, let's do Get‑Vegetable,

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and I'm going to filter this where the color is equal to green,

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and I'm using the simplified syntax.

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Sure enough, you can see that that works.

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Here is the same expression,

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but using the more traditional syntax with the script block and $_.

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We get the same result.

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But remember, you can use any property that you see with Get‑Member,

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and sometimes you need to look at Get‑Member

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because PowerShell will deceive you.

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Here is what I'm talking about.

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Let's do Get‑Vegetable, and let's filter where the color is equal to green,

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and I want the state to be raw.

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Do you see there on the screen?

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So I just want the raw vegetables that are green.

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Now, why is it cookedstate and not state?

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That's because I know from previous experience that the state property that

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you see listed there is something that PowerShell has added.

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That's not the real property name.

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The real property name that I see with Get‑Member is cookedstate,

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so that's the value that I need to use.

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So I'm going to pipe that result then and Sort on the

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Count property in Descending order, and there we go.

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So now I have all of the raw green vegetables sorted in

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descending order by the number of vegetables.

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Let's try an example that's more PowerShell, truly PowerShell related.

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Let's use the example from the slides where I'm going to

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Get‑Service for all the services that start with W where

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the Status is equal to running.

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Good.

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That worked just the way I wanted it to.

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Let's try something maybe that's a little more complex.

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Let me save a variable to hold the date for today to a variable called $now.

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So what I want to do is I'm going to get a directory listing of my

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scripts files Where the CreationTime property,

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which is something that I discovered in Get‑Member,

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is greater than 7 days ago,

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so I'm adding this little .NET trick here that Get‑Date,

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which has saved to $now, is a DateTime object.

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That DateTime object has an AddDays method, and I'm just subtracting 7 days.

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Now, I'm not sure I'm going to get anything,

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but hopefully I won't get an error, but let's see what happens.

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Oh, good.

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Alright, so there are a couple of files there that show up.

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And if I wanted to,

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I could also have done Get‑ChildItem ‑Recurse to search for all

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files because I have some subfolders there,

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but you can see that that worked.

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So Get‑ChildItem, the first part is limiting the search to just ps1 files,

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early filtering.

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The second half of that statement is using Where object,

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so it's saying, given all of the ps1 files now,

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now do the second set of filtering, look at the CreationTime,

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and if it's greater or equal to 7 days ago,

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keep that file object in the pipeline and send it on,

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and that's exactly what it did.

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I also want to point out or make sure you understand that you can

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use any code you want in that script block.

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I have a text file with some servers and my little test domain here,

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and I'm going to get the content of that file,

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so it's just going to be a list of names,

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and I'm going to pipe that to Where object,

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and now the script block for this is going to take that

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ComputerName from the text file and plug it into the parameter

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for ComputerName for Test‑Connection.

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This is kind of a PowerShell alternative to ping.

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So I'm going to do two pings, and the ‑Quiet will just return true or false.

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So what this will do is go through, and if the ComputerName can be pinged,

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then pass that name on into the pipeline.

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Any code can go in that script block as long as it returns true or false.

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And in this case, Test‑Connection with that ‑Quiet parameter,

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that's exactly what it's doing.

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It's returning either true or false.

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Alright, so finally,

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let's talk a little bit about this performance

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difference I've been talking about.

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I'm going to just take a look for discovery purposes.

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I'm going to get the win32_process class from Get‑Ciminstance

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and just grab a couple to take a look at,

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first 5.

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So I want to get that WorkingSetSize, and I'm going to do this,

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well,

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I'll use that text file of ComputerNames. So let's

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save the ComputerNames to a variable, and now what I'm going to do is I'm not,

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I don't really care about the results,

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I want to see how long it takes to get the results,

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so I'm going to use a new command called Measure‑Command.

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Measure‑Command, you then put whatever code you want to run in a script block,

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and it will run the code and then tell you how long

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it took for that code to run.

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I won't see the results of the command, only the results of how long it took.

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I want to measure how long does it take to do

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Get‑Ciminstance for all of the server names Where the

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WorkingSetSize is greater or equal to 50 MB,

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and that took about 252 ms.

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Make sure we understand what's going on here.

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I'm telling PowerShell,

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get all of the Win32 process objects from all, from my four or five servers,

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and then filter,

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and only keep the ones where the WorkingSetSize is greater or equal to 50 MB.

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That took 252 ms.

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That's not really the best way to do that.

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So let's do it what I think is the better way, the PowerShell way.

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So we'll do Get‑CimInstance again, same class,

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same number of computers, except this time,

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I'm going to apply filtering.

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So I'm going to say, using Get‑CimInstance,

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query on the server as you're looking at the Win32 processes,

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like a SQL query, if you will,

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only give me the objects Where the WorkingSetSize is greater or equal to,

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and that's the equivalent for 50 MB, that's the value then in bytes,

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and that took 66 ms.

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So that is significantly faster.

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And if you take this idea and scale it out,

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if you were doing, say, 100 servers,

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you'd really begin to see the benefits of filtering

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and doing things the right way.

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I can't stress enough the importance of getting into the

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habit of using good filtering practices.

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You never know when it will truly matter,

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so if you do it all the time, you don't have to think about it.

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And that brings our time in this course to an end.

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The key takeaway here is to learn and embrace the

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PowerShell paradigm of objects in the pipeline.

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Once you really understand this idea,

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you'll find PowerShell easier to use and wonder why

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you waited so long to learn it.

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Objects aren't complicated or mysterious.

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Use Get‑Member and Select‑Object to discover them.

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Once you know property names, you can use them everywhere.

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In fact, if you master the commands and concepts in this course,

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you can tackle just about anything in PowerShell.

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Need to work with something new, like Azure or VMware?

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Not a problem.

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Since you already know how PowerShell works,

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all you need to learn are the commands related to that technology.

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This course hopefully is a good start,

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but there's a lot more fundamentals that you'll need to learn,

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so I hope you'll join me in a future course. Thanks for watching.