WhatIf and Confirm support in PowerShell - Mini Project: Build & Apply

WhatIf and Confirm support

📖 Scenario: You are creating a PowerShell script to safely delete files. You want to add safety features so users can see what will happen before files are deleted and confirm the action.

🎯 Goal: Build a PowerShell script that supports -WhatIf and -Confirm parameters to safely delete files.

📋 What You'll Learn

Create a function called Remove-MyFile that deletes a file.

Add [CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')] to enable -WhatIf and -Confirm support.

Use $PSCmdlet.ShouldProcess() to check if the action should proceed.

Use Write-Verbose to show a message when deleting a file.

Test the function with -WhatIf and -Confirm parameters.

💡 Why This Matters

🌍 Real World

PowerShell scripts often delete files or make changes that can be risky. Using WhatIf and Confirm lets users preview or approve actions to avoid mistakes.

💼 Career

Many IT and automation jobs require writing safe scripts that support WhatIf and Confirm to prevent accidental data loss.

1

Create the Remove-MyFile function

Create a PowerShell function called Remove-MyFile that takes a parameter Path and deletes the file at that path using Remove-Item.

PowerShell

function Remove-MyFile {
    param(
        [string]$Path
    )
    # Your code here
}

Need a hint?

Use Remove-Item -Path $Path inside the function to delete the file.

2

Add CmdletBinding to support -WhatIf and -Confirm

Add [CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')] above the param block in the Remove-MyFile function to enable -WhatIf and -Confirm support.

PowerShell

[CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')]
function Remove-MyFile {
    param(
        [string]$Path
    )
    Remove-Item -Path $Path
    # Your code here
}

Need a hint?

Place [CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')] right before the function keyword.

3

Use $PSCmdlet.ShouldProcess() to confirm action

Inside the Remove-MyFile function, replace the direct Remove-Item call with a check using if ($PSCmdlet.ShouldProcess($Path, 'Remove file')). Only call Remove-Item if this returns true. Also add Write-Verbose to show a message before deleting.

PowerShell

[CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')]
function Remove-MyFile {
    param(
        [string]$Path
    )
    # Your code here
}

Need a hint?

Use if ($PSCmdlet.ShouldProcess($Path, 'Remove file')) { ... } to check before deleting.

4

Test the function with -WhatIf and -Confirm

Call Remove-MyFile with -Path set to "C:\temp\test.txt" and add the -WhatIf parameter to see what would happen. Then call it again with -Confirm to ask for confirmation.

PowerShell

[CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')]
function Remove-MyFile {
    param(
        [string]$Path
    )
    if ($PSCmdlet.ShouldProcess($Path, 'Remove file')) {
        Write-Verbose "Deleting file: $Path"
        Remove-Item -Path $Path
    }
}

# Your code here to test Remove-MyFile with -WhatIf and -Confirm

Need a hint?

Run Remove-MyFile -Path "C:\temp\test.txt" -WhatIf and Remove-MyFile -Path "C:\temp\test.txt" -Confirm to test.