Exploring Wait-Debugger in PowerShell

Welcome back to Wahmans PowerShell blog! Today, we are diving into a very handy cmdlet for debugging your scripts: Wait-Debugger. This powerful tool can help you pause execution of your script and enter the debugger at just the right moment.

What is Wait-Debugger?

According to the Microsoft documentation, Wait-Debugger stops a script in the debugger before running the next statement. In simpler terms, it behaves like an intentional breakpoint in your code. Once Wait-Debugger is hit during execution, the script will pause and open an interactive debugging session, allowing you to inspect variables, check logic, and step through your code manually.

Use Cases and Examples

Let’s walk through four examples, starting from beginner-friendly to more advanced usage.

Example 1: Basic Debugging

You’re running a script and just want to pause at a certain point to check variable values.

Write-Host "Starting script"
Wait-Debugger
Write-Host "This line comes after debugging"

When the script hits the Wait-Debugger line, it will pause, letting you inspect state and step through the rest.

Example 2: Conditional Debugging

Sometimes, you want the debugger to run only under certain conditions, such as a specific input or variable value.

$value = Read-Host "Enter a number"
if ($value -eq 42) {
    Write-Host "Special value detected. Entering debugger."
    Wait-Debugger
}
Write-Host "Script continues..."

Only if the user enters 42 will the debugger be activated.

Example 3: Integrated with Functions

You can use Wait-Debugger inside functions to troubleshoot smaller pieces of logic.

function Test-Math {
    param($a, $b)
    $result = $a + $b
    Wait-Debugger
    return $result
}

$result = Test-Math 5 7
Write-Host "Result: $result"

This allows you to debug just the function logic when it runs.

Example 4: Debugging Remote Scripts (Advanced)

If you’re debugging on a remote system where you’ve set up PowerShell remoting and have the debugger attached, you can pause the remote script as well.

Invoke-Command -ComputerName RemoteHost -ScriptBlock {
    Write-Host "Running on remote system"
    Wait-Debugger
    Write-Host "Resuming on remote system"
}

Note: The remote computer must have a debugger attached and available in the current session context.

Conclusion

Wait-Debugger is an invaluable tool for script development and debugging, whether you’re just starting out or working in a complex environment. Use it to insert logical pause points and take deep dives into your live code execution.

Happy scripting, and I will see you in the next post!