Category: Powershell

Shane O’Neill warns us to name our Powershell parameters:

Eh…what?

Cannot process argument because the value of argument “path” is null.

The “path” argument is NULL? And I’m back to the very root of “I:\”?

Thankfully, at this stage, I know to go back and read the help file again before I let slip any curses.

As usual, it’s a fun read and a good lesson.

Mike Robbins has a new video up:

If you follow me on Twitter, then I’m sure you’re aware that I’ve been using nothing but VS Code (Visual Studio Code) as a replacement for the PowerShell ISE (Integrated Scripting Environment) for the past couple of weeks and while I had tried it in the past, I didn’t previously think it was ready for prime time. That’s now changed with all of the updates and work that has gone into it. From what I’ve found, it works fairly well flawlessly so I’ve created a short and simple video to help others get VS Code installed and configured as a replacement for the PowerShell ISE.

Click through for some interesting comments, especially one from Mike Fal.

Shane O’Neill clarifies a misunderstanding in Powershell:

and you are running the following PowerShell command to check if the results contain a value…

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$String = "abc" $Array = @(Invoke-Sqlcmd -ServerInstance "SQLServer" -Database "Database" -Query "SELECT code FROM dbo.users") $Array.Contains($string)

It will return FALSE.

Now we know that the FALSE is false because we know that the string is in there!
This code is proven to work with arrays as stated here by the “Hey, Scripting Guy!”s so this was getting filed under “WTF PowerShell”

It’s a good post, so check it out and remember that DataRows aren’t strings.

Adam Bertram shows how to use regular expressions for pattern matching in Powershell:

However, regex has traditionally been a topic that most IT pros shy away from when they first see how it works. Admittedly, regex does take a bit of getting used to, and you’re still probably going to have to do some Googling every time you need to use it. But learning how PowerShell integrates regex into its language is a skill that’s much easier learned and one that will come in handy often.

First of all, when someone says “working with regex,” that can mean a lot of things so let’s break it down a little bit. Regex is a method of string matching. Its sole purpose is to match and parse strings from within other strings. This can mean a lot of things and PowerShell allows you to do just about anything here, particularly as it has the full power of the .NET Framework. For our purposes, let’s investigate a few ways PowerShell allows you to match strings and how to parse strings with regex and PowerShell.

Read on for a couple sample scenarios.

Klaas Vandenberghe notes a discrepancy in how Measure-Object works, based on syntax:

So, is the -InputObject parameter broken? Not really, but we need to be aware of the logic behind it.
Maybe we are used to work with -ComputerName for a lot of cmdlets and functions, and we rely blindly upon the ability of the command to handle whatever collection we provide. We know this executes the action we chose, like Get-DbaSqlService or Get-DbaOperatingSystemor whatever, separately to every computer in the collection. The collection is ‘fold out’, ‘unpacked’, ‘split’.

-InputObject doesn’t do that! Is that wrong? Not necessarily, it may be a choice of design to have possibilities to enquire the properties of the collection itself and those of the ‘members’ or ‘children’. It’s just a surprise the behaviour differs from pipeline input to parameter input.

Something to keep in mind when writing Powershell scripts.

Jeff Hicks shows off some of the niceties of Powershell’s ConvertTo-HTML cmdlet:

This is because Convertto-Html, like Export-CSV and Export-Clixml, take the entire object. This is not just the default result you see on the screen. Remember, everything will be treated as a string. In my example, if I want a similar HTML file, I will have to recreate the output with Select-Object. This might require piping the original result to Get-Member to discover the “real” property names.

It won’t output beautiful results, but with the appropriate CSS theming, you can generate good internal reports.