12 PowerShell Interview Questions

PowerShell is a powerful scripting language and command-line shell used for automating tasks and managing systems. It is an extremely valuable skill if you find yourself in a technical role such as Help Desk, System Administrator, or anything technical within an Windows environment. If you are prepping for a technical role and want to standout, having Powershell in your arsenal is a great first step.

Here are 12 PowerShell Interview Questions that might come up to test your knowledge and expertise.

1. What is PowerShell and how does it differ from Command Prompt?

PowerShell is an automation / configuration management from Microsoft. It has a command-line shell as scripting capabilities that were built on .NET framework. Although similarities, Command Prompt primarily works with text commands, while Powershell gives users the ability to work with objects making it much more effective in handling complex tasks.

2. Can you explain what cmdlets are?

Cmdlets are lightweight commands built into Powershell or available from downloaded modules in the PowerShell environment. They are the building blocks of PowerShell scripts and are designed to perform specific tasks, like managing files or processes. Cmdlets follow a verb-noun naming convention (e.g., Get-Process, Set-Location). For example if you are working Active Directory you will likely find yourself working with the Active Directory module Cmdlets built specifically to interact with Active Directory.

3. How do you create a new PowerShell script?

To create a new PowerShell script, you can use any text editor, such as Notepad, Visual Studio Code, or the PowerShell Integrated Scripting Environment (ISE). Save the file with a .ps1 extension, and then you can run it by calling the script file in the PowerShell terminal. If you are using Powershell almost daily, you will likely be equipped with some sort of ISE to help you build out more complex scripts.

4. What are some common cmdlets used in PowerShell?

Some common cmdlets include:

• Get-Help: Provides help information for cmdlets.

• Get-Command: Lists all cmdlets, functions, workflows, aliases installed on the system.

• Get-Service: Lists all services on the system.

• Get-Process: Provides information about processes running on the system.

• Set-ExecutionPolicy: Changes the user preference for PowerShell script execution.

5. How can you execute a PowerShell script?

To execute a PowerShell script, you need to open the PowerShell terminal and type the path to the script file. For example, .\script.ps1 will run a script named script.ps1 located in the current directory. Ensure the execution policy allows running scripts. As PowerShell deals with scripts and scripts can sometimes be crafted for malicious purposes, often times you will need specific permissions / rights on your account to even run them. For example, you may be provisioned with an account with elevated permissions to run specific scripts, which would have to be the account the script is ran from.

6. What is the purpose of the Get-Help cmdlet?

The Get-Help cmdlet provides detailed information about cmdlets, including syntax, parameters, examples, and descriptions. It’s an essential tool for learning how to use different cmdlets and functions in PowerShell. This is likely to come into play during an interview as you may be questioned about something you may have not used before in Powershell. The get-help cmdlet will aid you in figuring out exactly what a cmdlet does and what parameter it takes, all built in right from the Powershell interface.

7. How would you handle errors in PowerShell scripts?

Error handling essentially provides a script with actions to perform if it encounters an error as opposed to automatically ending the script right there. Also working with errors can allow you to troubleshot exactly what is going on within a script when debugging.

PowerShell provides several ways to handle errors, including:

• Try-Catch-Finally: This construct allows you to try a block of code, catch any errors that occur, and optionally execute a block of code regardless of the result.

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try {

    # Code that may produce an error

} catch {

    # Code to handle the error

} finally {

    # Code that runs regardless of the result

}

• Error Variables: $Error automatic variable stores a collection of error objects.

• ErrorAction Parameter: Controls how cmdlets respond to non-terminating errors.

8. What are PowerShell aliases?

Aliases in PowerShell are alternate names or shortcuts for cmdlets and commands. They are used to simplify command entry and can make scripts more readable. For example, dir is an alias for the Get-ChildItem cmdlet. Think of it as simply a shortcut.

9. Can you explain the concept of piping in PowerShell?

Piping in PowerShell allows you to pass the output of one cmdlet as input to another cmdlet using the | operator. This helps in chaining multiple commands to perform complex tasks in a streamlined manner. It allows you to essentially take the output of one command, and use that output within the next step of the piped sequence. This is helpful for longer lines of code that are dependent on the results from the previous step. For example:

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Get-Process | Where-Object {$_.CPU -gt 100} | Select-Object -Property Name, CPU

10. How do you manage background jobs in PowerShell?

PowerShell supports running commands and scripts as background jobs using the Start-Job cmdlet. You can check the status of jobs with Get-Job, receive the results with Receive-Job, and remove them with Remove-Job.

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$job = Start-Job -ScriptBlock { Get-Process }

Get-Job -Id $job.Id

Receive-Job -Id $job.Id

Remove-Job -Id $job.Id

11. What is the purpose of the Invoke-Command cmdlet?

The Invoke-Command cmdlet is used to run commands on local and remote computers. It’s essential for remote administration and automation tasks across multiple machines.

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Invoke-Command -ComputerName Server01 -ScriptBlock { Get-Process }

12. How can you import and use modules in PowerShell?

Modules in PowerShell are packages that contain cmdlets, providers, functions, workflows, variables, and aliases. To use a module, you first need to import it using the Import-Module cmdlet. You can list available modules with Get-Module -ListAvailable and import a module as follows:

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Import-Module -Name ModuleName

These questions cover the fundamentals and some advanced features of PowerShell, providing a solid basis for interview preparation. Remember, practical experience and understanding the core concepts will go a long way in acing your PowerShell interview.