Скачать или смотреть Getting the Value of an Environment Variable with PowerShell

Discover how to easily retrieve the value of an environment variable using PowerShell, even when its name is stored in another variable.
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This video is based on the question https://stackoverflow.com/q/69311346/ asked by the user 'René Nyffenegger' ( https://stackoverflow.com/u/180275/ ) and on the answer https://stackoverflow.com/a/69313517/ provided by the user 'Mathias R. Jessen' ( https://stackoverflow.com/u/712649/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Retrieve the Value of an Environment Variable in PowerShell

PowerShell is a robust command-line shell and scripting language that provides a powerful way to manipulate system settings and automate tasks. One common task is to retrieve environmental variables, especially when their names are stored in another variable. This guide will walk you through how to effectively achieve this in a simple manner.

The Challenge: Accessing Environment Variable Values

You may find yourself in a situation where you have the name of an environment variable stored in a variable. For example:

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Now, you want to get the value of the TEMP environment variable but might be unsure of the most straightforward way to do so. A common approach some might consider is using Invoke-Expression:

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While this works, is there a more direct and cleaner alternative?

The Solution: Using Get-Item for Environment Variables

Yes! There is a more clear and elegant approach. PowerShell includes a built-in PSDrive called env: that allows you to access environment variables directly. You can retrieve the value of an environment variable using the Get-Item cmdlet.

Here’s the simple command you can use:

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Breakdown of the Command:

Get-Item: This cmdlet retrieves the specified item, which in this case is an environment variable.

-Path env:$varName: Here, you specify the path to the environment variable, utilizing the env: PSDrive and the variable containing the name ($varName).

.Value: This property of the returned item gives you the actual value of the environment variable.

Benefits of Using Get-Item:

Clarity: This method is much clearer than using Invoke-Expression, making your intentions obvious.

Safety: It avoids potential security risks associated with Invoke-Expression.

Simplicity: It's straightforward and more in line with PowerShell practices.

Conclusion

Retrieving the value of an environment variable when its name is stored in a variable doesn't have to be complicated. By using the Get-Item cmdlet along with the env: PSDrive, you can achieve this easily and safely. Next time you find yourself in this situation, remember this method for a clean and efficient solution.

Summary

In summary, if you ever need to access an environment variable value with PowerShell, remember to utilize Get-Item with the env: PSDrive. It's a powerful feature that can help streamline your scripting tasks.