Why cross-platform extends reach in PowerShell - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print a message about cross-platform reach.

PowerShell

Write-Output [1]

Drag options to blanks, or click blank then click option'

Aecho Cross-platform scripts run on many systems.

B"Cross-platform scripts run on many systems."

CWrite-Output 'Cross-platform scripts run on many systems.'

DCross-platform scripts run on many systems.

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the string in quotes.

Using echo instead of Write-Output in PowerShell.

In PowerShell, strings must be in quotes to be printed correctly with Write-Output.

2fill in blank

medium

Complete the code to check the operating system platform.

PowerShell

$platform = [System.Environment]::OSVersion.Platform; if ($platform -eq [1]) { Write-Output "Windows detected" }

Drag options to blanks, or click blank then click option'

AWin32NT

B"Unix"

C"Darwin"

D"Linux"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong string for Windows platform.

Confusing platform strings with other OSes.

In PowerShell Core, the platform value "Win32NT" represents Windows OS.

3fill in blank

hard

Fix the error in the script to detect Linux platform.

PowerShell

if ([System.Environment]::OSVersion.Platform -eq [1]) { Write-Output "Linux detected" }

Drag options to blanks, or click blank then click option'

A"OSX"

B"Win32NT"

CUnix

D"Darwin"

Attempts:

3 left

💡 Hint

Common Mistakes

Using "Win32NT" or other strings which represent other platforms.

Not using the correct platform string for Linux.

Platform value "Unix" represents Unix/Linux systems in PowerShell Core.

4fill in blank

hard

Fill both blanks to create a cross-platform script that prints OS name.

PowerShell

$os = (Get-CimInstance -ClassName Win32_OperatingSystem -ErrorAction SilentlyContinue).[1]; if (-not $os) { $os = (uname).[2] }; Write-Output $os

Drag options to blanks, or click blank then click option'

ACaption

BToString

COutput

DName

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong property names for OS detection.

Not converting uname output to string.

On Windows, 'Caption' gives the OS name; on Unix, 'uname' output converted to string shows OS.

5fill in blank

hard

Fill all three blanks to create a script that runs a command based on OS platform.

PowerShell

switch ([System.Environment]::OSVersion.Platform) { "Win32NT" { [1] 'dir' } "Unix" { [2] 'ls' } default { [3] 'Unsupported OS' } }

Drag options to blanks, or click blank then click option'

AWrite-Output

BInvoke-Expression

CWrite-Host

DStart-Process

Attempts:

3 left

💡 Hint

Common Mistakes

Using Write-Output instead of running commands.

Not handling default case properly.

Invoke-Expression runs 'dir' (PowerShell alias for Get-ChildItem) on Windows; Invoke-Expression runs 'ls' on Unix/Linux; Write-Output prints message for unsupported OS.

Practice

1. Why is writing cross-platform PowerShell scripts important?

easy

A. They only work on Windows systems

B. They can run on Windows, Linux, and macOS without changes

C. They require special hardware to run

D. They are slower than platform-specific scripts

Solution

1. Step 1: Understand cross-platform meaning

   Cross-platform means the script runs on multiple operating systems like Windows, Linux, and macOS.

2. Step 2: Identify the benefit of cross-platform scripts

   Scripts that run on many systems reach more users and environments without rewriting code.

3. Final Answer:

   They can run on Windows, Linux, and macOS without changes -> Option B

4. Quick Check:

   Cross-platform = Runs everywhere [OK]

Hint: Cross-platform means runs on many OS types [OK]

Common Mistakes:

• Thinking cross-platform means Windows only
• Assuming special hardware is needed
• Believing cross-platform scripts are slower

2. Which PowerShell command syntax is correct for checking the OS platform in a cross-platform script?

easy

A. if ($env:OS -eq 'Linux') { Write-Host 'Linux' }

B. if ($PSVersionTable.OS -eq 'Windows') { Write-Host 'Windows' }

C. if ($PSVersionTable.Platform -eq 'Unix') { Write-Host 'Linux or macOS' }

D. if ($Platform -eq 'Unix') { Write-Host 'Unix' }

Solution

1. Step 1: Identify correct property for OS platform

   $PSVersionTable.Platform is the standard way to check OS platform in PowerShell Core.

2. Step 2: Check syntax correctness

   if ($PSVersionTable.Platform -eq 'Unix') { Write-Host 'Linux or macOS' } uses correct syntax and property. Others use invalid or non-existent properties.

3. Final Answer:

   if ($PSVersionTable.Platform -eq 'Unix') { Write-Host 'Linux or macOS' } -> Option C

4. Quick Check:

   Use $PSVersionTable.Platform for OS check [OK]

Hint: Use $PSVersionTable.Platform to detect OS [OK]

Common Mistakes:

• Using $env:OS which is Windows-only
• Referencing non-existent $PSVersionTable.OS
• Using undefined variable $Platform

3. What will this PowerShell Core script output on a Linux system?

if ($PSVersionTable.Platform -eq 'Unix') { 'Cross-platform script running' } else { 'Windows script running' }

medium

A. Cross-platform script running

B. Windows script running

C. Error: Property not found

D. No output

Solution

1. Step 1: Understand $PSVersionTable.Platform on Linux

   On Linux, $PSVersionTable.Platform equals 'Unix'.

2. Step 2: Evaluate the if condition

   The condition is true, so the script outputs 'Cross-platform script running'.

3. Final Answer:

   Cross-platform script running -> Option A

4. Quick Check:

   Linux means Platform='Unix' => Output A [OK]

Hint: On Linux, Platform is 'Unix' so if condition is true [OK]

Common Mistakes:

• Assuming Platform is 'Linux' instead of 'Unix'
• Expecting Windows output on Linux
• Thinking script throws error

4. This script is intended to run on Windows and Linux but uses a Windows-only environment variable. What is the problem?

if ($env:OS -eq 'Windows_NT') { Write-Host 'Windows' } else { Write-Host 'Linux or macOS' }

medium

A. The else block syntax is incorrect

B. Missing parentheses around condition

C. Write-Host is not supported on Linux

D. Using $env:OS is Windows-only and undefined on Linux

Solution

1. Step 1: Check environment variable usage

   $env:OS is defined only on Windows, so on Linux it is empty or undefined.

2. Step 2: Understand the problem with $env:OS

   Because $env:OS is missing on Linux, the script relies on a Windows-specific variable, making it non-portable.

3. Final Answer:

   Using $env:OS is Windows-only and undefined on Linux -> Option D

4. Quick Check:

   $env:OS is Windows-only env var [OK]

Hint: Avoid Windows-only env vars for cross-platform scripts [OK]

Common Mistakes:

• Thinking Write-Host is unsupported on Linux
• Believing parentheses are required around if condition
• Assuming else syntax is wrong

5. You want to write a PowerShell script that lists files differently on Windows and Linux but works on both. Which approach best extends your script's reach?

hard

A. Use $PSVersionTable.Platform to detect OS and run platform-specific commands

B. Use Windows-only cmdlets and expect errors on Linux

C. Write separate scripts for each OS and run manually

D. Ignore OS differences and run same commands everywhere

Solution

1. Step 1: Identify cross-platform detection method

   Using $PSVersionTable.Platform lets the script detect OS at runtime.

2. Step 2: Apply platform-specific commands conditionally

   Run Windows commands if on Windows, Linux commands if on Unix, ensuring script works everywhere.

3. Final Answer:

   Use $PSVersionTable.Platform to detect OS and run platform-specific commands -> Option A

4. Quick Check:

   Detect OS, run matching commands = best cross-platform practice [OK]

Hint: Detect OS, then run matching commands for best reach [OK]

Common Mistakes:

• Using Windows-only commands without checks
• Writing separate scripts instead of one cross-platform script
• Ignoring OS differences causing failures