Platform-specific considerations in PowerShell - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the current user's home directory in PowerShell.

PowerShell

Write-Output $[1]

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

AHOME

B$env:USERPROFILE

Cenv:PATH

DUSER

Attempts:

3 left

💡 Hint

Common Mistakes

Using $HOME which is common in Linux but not in Windows PowerShell.

Using $USER which is not defined in PowerShell.

In PowerShell, the current user's home directory is stored in the environment variable USERPROFILE. Access it using $env:USERPROFILE.

2fill in blank

medium

Complete the code to check if the current OS is Windows in PowerShell.

PowerShell

if ($PSVersionTable.OS -[1] 'Windows') { Write-Output 'Windows OS' }

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

A-match

B-eq

C-like

D-contains

Attempts:

3 left

💡 Hint

Common Mistakes

Using -eq which requires exact match.

Using -contains which is for collections, not strings.

The -match operator performs a regex match. Since $PSVersionTable.OS contains a string with OS info, -match 'Windows' checks if 'Windows' is part of that string.

3fill in blank

hard

Fix the error in the code to list all files in the current directory on Linux using PowerShell.

PowerShell

Get-ChildItem -Path . | Where-Object { $_.[1] -eq $false }

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

APSIsContainer

BType

CMode

DFileType

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Type' or 'Mode' which do not directly indicate file or folder.

Checking for 'File' string which is not a property value.

The property PSIsContainer is $true for directories and $false for files. To list files, check where PSIsContainer is $false.

4fill in blank

hard

Fill both blanks to create a dictionary of file names and sizes for files larger than 1MB in the current directory.

PowerShell

$files = @{ } ; Get-ChildItem -File | Where-Object { $_.Length [1] 1MB } | ForEach-Object { $files[[2]] = $_.Length }

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

A>

BName

CLength

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > for size comparison.

Using Length as dictionary key instead of Name.

Use > to filter files larger than 1MB. Use Name as the key in the dictionary to store file sizes.

5fill in blank

hard

Fill all three blanks to create a list of process names running with more than 100 MB memory usage.

PowerShell

$heavyProcs = Get-Process | Where-Object { $_.[1] [2] 100MB } | Select-Object -ExpandProperty [3]

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

AWorkingSet64

B>

CProcessName

DId

Attempts:

3 left

💡 Hint

Common Mistakes

Using Id instead of ProcessName for output.

Using < instead of > for filtering memory usage.

WorkingSet64 gives memory usage in bytes. Use > to filter processes using more than 100MB. Select the ProcessName property to get the names.

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