Invoke-Command in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Invoke-Command script?

Consider this PowerShell script that runs a command on a remote computer named 'Server01'. What will be the output?

PowerShell

Invoke-Command -ComputerName Server01 -ScriptBlock { Get-Date -Format 'yyyy-MM-dd' }

A The current date on Server01 in 'yyyy-MM-dd' format, e.g., '2024-06-15'

B The current date on the local computer in 'yyyy-MM-dd' format

C An error saying 'ComputerName Server01 not found'

D No output, the command runs silently

💡 Hint

Invoke-Command runs the script block on the remote computer specified by -ComputerName.

Invoke-Command runs the script block on the remote computer 'Server01', so the output is the date on that remote machine, not the local one.

📝 Syntax

intermediate

Which option correctly uses Invoke-Command to run a script block on multiple computers?

You want to run the command 'hostname' on two remote computers: 'PC1' and 'PC2'. Which syntax is correct?

A Invoke-Command -ComputerName PC1, PC2 -ScriptBlock { hostname }

B Invoke-Command -ComputerName 'PC1 PC2' -ScriptBlock { hostname }

C Invoke-Command -ComputerName @('PC1','PC2') -ScriptBlock { hostname }

D Invoke-Command -ComputerName ['PC1','PC2'] -ScriptBlock { hostname }

💡 Hint

The -ComputerName parameter accepts a comma-separated list of computer names.

The correct way is to pass multiple computer names as an array or comma-separated list. Option C is correct syntax.

🔧 Debug

advanced

Why does this Invoke-Command script fail with an error?

This script tries to run a command on a remote computer but fails. What is the cause?

PowerShell

Invoke-Command -ComputerName Server01 -ScriptBlock { Get-Process } -Credential $null

A The script block is invalid because Get-Process cannot run remotely.

B Passing $null to -Credential causes an error because a valid credential is required for remote sessions.

C The ComputerName parameter is missing quotes around Server01.

D Invoke-Command does not support the -Credential parameter.

💡 Hint

Check the use of the -Credential parameter and what values it accepts.

Passing $null to -Credential is invalid because it expects a PSCredential object or nothing. This causes the command to fail.

🚀 Application

advanced

How to capture output from multiple remote computers using Invoke-Command?

You want to run 'Get-Service' on 'ServerA' and 'ServerB' and save the combined output locally. Which script achieves this?

A $results = Invoke-Command -ComputerName ServerA, ServerB -ScriptBlock { Get-Service }; $results

B Invoke-Command -ComputerName ServerA, ServerB -ScriptBlock { Get-Service } | Out-File services.txt

C $results = Invoke-Command -ComputerName ServerA -ScriptBlock { Get-Service }; $results += Invoke-Command -ComputerName ServerB -ScriptBlock { Get-Service }; $results

D Invoke-Command -ComputerName ServerA, ServerB -ScriptBlock { Get-Service } > services.txt

💡 Hint

Invoke-Command returns output objects that can be stored in a variable.

Option A runs the command on both servers and stores all output in $results as a combined collection.

🧠 Conceptual

expert

What happens if you use Invoke-Command with -AsJob parameter?

You run this command: Invoke-Command -ComputerName Server01 -ScriptBlock { Start-Sleep -Seconds 10; 'Done' } -AsJob. What is the behavior?

A The command runs asynchronously but outputs 'Done' immediately.

B The command runs synchronously and outputs 'Done' after 10 seconds.

C The command fails because -AsJob cannot be used with Invoke-Command.

D The command runs asynchronously as a background job; you must use Receive-Job to get the output later.

💡 Hint

The -AsJob parameter runs the command in the background.

Using -AsJob runs the command asynchronously as a background job. Output is not immediate and must be retrieved with Receive-Job.