Quick Learn – PSMonday #14: Monday, August 1, 2016

Topic: PowerShell Remoting Continued III

Notice: This post is a part of the PowerShell Monday series — a group of quick and easy to read mini lessons that briefly cover beginning and intermediate PowerShell topics. As a PowerShell enthusiast, this seemed like a beneficial way to ensure those around me at work were consistently learning new things about Windows PowerShell. At some point, I decided I would share these posts here, as well. Here’s the PowerShell Monday Table of Contents.

Last week, we discussed how to get a locally created variable into a PS Remoting session, by taking advantage of the Using scope modifier — a feature that was added in Windows PowerShell 3.0. Today, we’ll go over how we did it in earlier versions.

In PowerShell 2.0 the Using scope modifier didn’t yet exist. To get locally declared variables into a PS Remoting session took a bit more work. Below are two examples, beginning with the most preferred, first.

The first below example requires the use of the Param block inside the value provided to Invoke-Command’s -ScriptBlock parameter. It also requires the use of Invoke-Command’s -ArgumentList parameter. The $LocalVariable was set last week with the name of the local computer. This time, we’ll take two variables into the PS Remoting session, right after we define the $Date variable. I’ve added a couple blank lines inside the script block, to make things a bit easier to read.

$Date = Get-Date

Invoke-Command -ComputerName MEMSRV01 -ScriptBlock {
    Param($String1,$String2)

    "The local computer is $String1."
    "The local recorded date and time is $String2."
    "The remote computer is $env:COMPUTERNAME."

} -ArgumentList $LocalVariable,$Date

The local computer is TOMMYSPC.
The local recorded date and time is 07/30/2016 09:30:50.
The remote computer is MEMSRV01.

So we’re sure we know what happened here, $LocalVariable went to the remote session and became the value provided to $String1, and $Date was the value provided to $String2.

Our final example uses the $args variable without the need for the Param block. It still requires the -ArgumentList parameter, however. Although this method requires a little less work, using the $args variable can become confusing and so this option should be saved for last. Realistically, it should never be used, as you can always use the above example when you’re working with PowerShell 2.0.

Invoke-Command -ComputerName MEMSRV01 -ScriptBlock {

    "The local computer is $($args[0])."
    "The local recorded date and time is $($args[1])."
    "The remote computer is $env:COMPUTERNAME."

} -ArgumentList $LocalVariable,$Date

The local computer is TOMMYSPC.
The local recorded date and time is 07/30/2016 09:30:50.
The remote computer is MEMSRV01.

And that’s how we get our local variables into our PS Remoting sessions, if the Using scope modifier isn’t an option.

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