Debugging

Look at the data

Most PowerShell bugs come from data not being what you think. Check types, counts, and properties:

$result = 'web01'
$result.GetType().Name
@($result).Count
[pscustomobject]@{ Name = 'web01'; Port = 443 } | Format-List *

String
1

Name : web01
Port : 443

Format-List * shows every property; Get-Member shows the type and members.

Strict mode

Set-StrictMode turns silent mistakes into errors:

Set-StrictMode -Version Latest
$user = [pscustomobject]@{ Name = 'Ada' }
try { $user.Nmae } catch { $_.Exception.Message }
try { $undefinedVariable } catch { $_.Exception.Message }

The property 'Nmae' cannot be found on this object. Verify that the property exists.
The variable '$undefinedVariable' cannot be retrieved because it has not been set.

Without strict mode, both lines would silently return $null. Put Set-StrictMode -Version Latest at the top of scripts.

Verbose and debug output

Sprinkle Write-Verbose through advanced functions and run them with -Verbose to trace what happens — the messages stay out of the data and are invisible otherwise.

Breakpoints

In VS Code, click left of a line number to set a breakpoint and press F5. Execution pauses there; you can inspect variables, step through lines (F10), step into functions (F11), and type expressions in the debug console.

From the console, set breakpoints with Set-PSBreakpoint:

# illustrative
Set-PSBreakpoint -Script .\deploy.ps1 -Line 42
Set-PSBreakpoint -Script .\deploy.ps1 -Variable total -Mode Write
.\deploy.ps1

At the [DBG] prompt, type s (step into), v (step over), o (step out), c (continue), k (call stack), or any expression. Adding Wait-Debugger to a script pauses it at that line.

Tracing commands

Set-PSDebug -Trace 1 prints each line as it runs — like set -x in Bash. Turn it off with Set-PSDebug -Off.

What's next

Try the Intermediate Projects, then move on to Level 3 — Advanced: classes, .NET, parallelism, remoting, and building production-ready modules.