Platform-specific considerations in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

PowerShell script output on Windows vs Linux

What is the output of this PowerShell script when run on Windows and Linux respectively?

PowerShell

Write-Output $PSVersionTable.PSPlatform

A "WindowsNT" on Windows, "Unix" on Linux

B "Windows" on Windows, "Linux" on Linux

C "Win32" on Windows, "Linux" on Linux

D "Win32NT" on Windows, "Unix" on Linux

💡 Hint

Check the $PSVersionTable automatic variable for platform info.

The $PSVersionTable.PSPlatform property returns 'Win32NT' on Windows and 'Unix' on Linux/macOS in PowerShell.

📝 Syntax

intermediate

Correct path separator in PowerShell scripts

Which option correctly sets a file path variable that works on both Windows and Linux in PowerShell?

A $path = "C:\Users\Public\Documents\file.txt"

B $path = "C:/Users/Public/Documents/file.txt"

C $path = Join-Path -Path 'C:' -ChildPath 'Users/Public/Documents/file.txt'

D $path = Join-Path -Path 'C:' -ChildPath 'Users\Public\Documents\file.txt'

💡 Hint

PowerShell accepts forward slashes as path separators on all platforms.

Using forward slashes '/' in paths works on both Windows and Linux in PowerShell, making option B correct.

🔧 Debug

advanced

Identify the error in this cross-platform PowerShell script

What error will this script produce when run on Linux PowerShell?

PowerShell

if (Test-Path "C:\Windows") { Write-Output "Windows folder exists" } else { Write-Output "Folder not found" }

A Outputs "Folder not found"

B Outputs "Windows folder exists"

C Throws a runtime error because the path is invalid on Linux

D Throws a syntax error due to backslashes

💡 Hint

Consider how Test-Path behaves with Windows paths on Linux.

On Linux, the path 'C:\Windows' does not exist, so Test-Path returns false and the script outputs 'Folder not found'.

🚀 Application

advanced

Write a PowerShell snippet to detect OS and print a message

Which snippet correctly detects the OS platform and prints 'Running on Windows' or 'Running on Linux' accordingly?

A if ($IsWindows) { Write-Output 'Running on Windows' } else { Write-Output 'Running on Linux' }

B if ($env:OS -eq 'Windows_NT') { Write-Output 'Running on Windows' } else { Write-Output 'Running on Linux' }

C switch ($PSVersionTable.PSPlatform) { 'Win32NT' { Write-Output 'Running on Windows' }; 'Unix' { Write-Output 'Running on Linux' } }

D if ($PSVersionTable.Platform -eq 'Windows') { Write-Output 'Running on Windows' } else { Write-Output 'Running on Linux' }

💡 Hint

Use $PSVersionTable.PSPlatform for reliable platform detection.

Option C uses the correct property $PSVersionTable.PSPlatform with a switch statement to detect 'Win32NT' or 'Unix'.

🧠 Conceptual

expert

Why is using environment variables for platform detection preferred in PowerShell scripts?

Which reason best explains why environment variables like $env:OS are less reliable than $PSVersionTable.PSPlatform for platform detection in PowerShell?

A $env:OS is not set on Linux and macOS, causing inconsistent results.

B $PSVersionTable.PSPlatform is deprecated and should not be used.

C $env:OS always returns 'Windows_NT' regardless of platform.

D $PSVersionTable.PSPlatform only works on Windows PowerShell, not PowerShell Core.

💡 Hint

Think about environment variables availability across platforms.

The environment variable $env:OS is typically only set on Windows, so relying on it can cause scripts to fail or misdetect on Linux/macOS.

Practice

1. Which automatic variable in PowerShell helps you detect if the script is running on Windows?

easy

A. $IsLinux

B. $IsWindows

C. $IsMacOS

D. $Platform

Solution

1. Step 1: Understand platform detection variables

   PowerShell provides automatic variables like $IsWindows, $IsLinux, and $IsMacOS to detect the current OS.

2. Step 2: Identify the variable for Windows

   $IsWindows is true only when running on Windows, while others are for Linux or MacOS.

3. Final Answer:

   $IsWindows -> Option B

4. Quick Check:

   Windows detection = $IsWindows [OK]

Hint: Remember $IsWindows is true only on Windows systems [OK]

Common Mistakes:

• Confusing $IsLinux or $IsMacOS as Windows variables
• Using $Platform which does not exist
• Assuming $IsWindows works on Linux or Mac

2. Which of the following is the correct syntax to run platform-specific code only on Linux in PowerShell?

easy

A. if ($IsUnix) { Write-Host 'Running on Linux' }

B. if ($IsWindows) { Write-Host 'Running on Linux' }

C. if ($IsMacOS) { Write-Host 'Running on Linux' }

D. if ($IsLinux) { Write-Host 'Running on Linux' }

Solution

1. Step 1: Identify the variable for Linux

   $IsLinux is the automatic variable that is true only on Linux systems.

2. Step 2: Check the syntax for conditional execution

   The syntax if ($IsLinux) { ... } runs the block only on Linux.

3. Final Answer:

   if ($IsLinux) { Write-Host 'Running on Linux' } -> Option D

4. Quick Check:

   Linux code block = if ($IsLinux) [OK]

Hint: Use if ($IsLinux) for Linux-specific code blocks [OK]

Common Mistakes:

• Using $IsWindows or $IsMacOS for Linux code
• Using undefined variable $IsUnix
• Incorrect if statement syntax

3. What will be the output of this PowerShell script when run on macOS?

if ($IsWindows) { Write-Output 'Windows' } elseif ($IsLinux) { Write-Output 'Linux' } elseif ($IsMacOS) { Write-Output 'MacOS' } else { Write-Output 'Unknown' }

medium

A. MacOS

B. Linux

C. Windows

D. Unknown

Solution

1. Step 1: Understand the platform variables

   On macOS, $IsMacOS is true, while $IsWindows and $IsLinux are false.

2. Step 2: Follow the conditional logic

   The script checks $IsWindows (false), then $IsLinux (false), then $IsMacOS (true), so it outputs 'MacOS'.

3. Final Answer:

   MacOS -> Option A

4. Quick Check:

   macOS detection outputs 'MacOS' [OK]

Hint: Check $IsMacOS true for Mac output in if-elseif chain [OK]

Common Mistakes:

• Assuming Linux output on macOS
• Ignoring else block
• Confusing $IsWindows with $IsMacOS

4. You wrote this PowerShell script to run only on Windows:

if ($IsWindows) {
  Write-Output 'Windows detected'
} else {
  Write-Output 'Not Windows'
}

But it always outputs 'Not Windows' even on Windows. What is the likely problem?

medium

A. You ran the script in PowerShell Core on Windows but $IsWindows is true only in Windows PowerShell

B. You ran the script in PowerShell Core on Windows where $IsWindows is false

C. You ran the script in Windows PowerShell 5.1 on Windows where $IsWindows does not exist

D. You used $IsWindows without the $ sign

Solution

1. Step 1: Understand $IsWindows availability

   The $IsWindows automatic variable exists only in PowerShell Core 6.0+ and is true on Windows.

2. Step 2: Identify the likely problem

   In legacy Windows PowerShell 5.1, $IsWindows does not exist ($null/false), so the if condition fails even on Windows.

3. Final Answer:

   You ran the script in Windows PowerShell 5.1 on Windows where $IsWindows does not exist -> Option C

4. Quick Check:

   $IsWindows unavailable in PS 5.1 [OK]

Hint: Verify your PowerShell edition (powershell.exe vs pwsh.exe) [OK]

Common Mistakes:

• Forgetting $ sign on variable
• Assuming $IsWindows always true on Windows
• Confusing PowerShell Core and Windows PowerShell behavior

5. You want to write a PowerShell script that creates a folder named 'Logs' only on Windows and macOS, but skips Linux. Which code snippet correctly implements this platform-specific behavior?

hard

A. if ($IsWindows -or $IsMacOS) { New-Item -ItemType Directory -Path './Logs' }

B. if ($IsLinux) { New-Item -ItemType Directory -Path './Logs' }

C. if ($IsWindows -and $IsMacOS) { New-Item -ItemType Directory -Path './Logs' }

D. if ($IsUnix) { New-Item -ItemType Directory -Path './Logs' }

Solution

1. Step 1: Understand platform conditions

   You want to create the folder only on Windows or macOS, so the condition should check if either $IsWindows or $IsMacOS is true.

2. Step 2: Analyze each option

   if ($IsWindows -or $IsMacOS) { New-Item -ItemType Directory -Path './Logs' } uses -or to combine $IsWindows and $IsMacOS correctly. if ($IsLinux) { New-Item -ItemType Directory -Path './Logs' } creates folder only on Linux (wrong). if ($IsWindows -and $IsMacOS) { New-Item -ItemType Directory -Path './Logs' } uses -and which requires both true (impossible). if ($IsUnix) { New-Item -ItemType Directory -Path './Logs' } uses undefined $IsUnix which is falsey (wrong).

3. Final Answer:

   if ($IsWindows -or $IsMacOS) { New-Item -ItemType Directory -Path './Logs' } -> Option A

4. Quick Check:

   Use -or for Windows or Mac condition [OK]

Hint: Use -or to combine platform checks for multiple OS [OK]

Common Mistakes:

• Using -and instead of -or for multiple platforms
• Creating folder on Linux by mistake
• Using undefined variables like $IsUnix