PowerShell Windows Development Skill

A Claude Code skill for Windows automation with PowerShell — covering cmdlet patterns, pipeline operations, Active Directory management, registry operations, and Windows-specific scripting best practices.

When to Use This Skill

Choose this skill when:

• Automating Windows system administration tasks
• Writing PowerShell scripts for deployment and configuration
• Managing Active Directory, IIS, or Windows services
• Working with the Windows registry and file system
• Building CI/CD scripts for Windows environments
• Debugging PowerShell syntax and operator issues

Consider alternatives when:

• You need cross-platform shell scripts (use Bash)
• You need Linux system administration (use a Linux shell skill)
• You need .NET application development (use a C# skill)

Quick Start

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# Check PowerShell version
$PSVersionTable.PSVersion

# Run a script
.\script.ps1

# Set execution policy (required for scripts)
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

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# Production-ready script template
#Requires -Version 7.0
[CmdletBinding()]
param(
    [Parameter(Mandatory)]
    [string]$Environment,

    [ValidateSet('Deploy', 'Rollback', 'Status')]
    [string]$Action = 'Status'
)

$ErrorActionPreference = 'Stop'

try {
    Write-Host "Running $Action for $Environment"
    # Script logic here
} catch {
    Write-Error "Failed: $_"
    exit 1
} finally {
    Write-Host "Script completed"
}

Core Concepts

Critical Syntax Rules

Wrong	Correct	Why
if ($a -eq $b) {}	if ($a -eq $b) { }	Braces on same line
$array.Count -gt 0	($array.Count) -gt 0	Parentheses around property access
"text" + $var + "text"	"text ${var} text"	String interpolation
$result = cmd /arg	$result = & cmd /arg	Call operator for executables

Pipeline Operations

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# Filter, transform, sort
Get-Process |
    Where-Object { $_.WorkingSet64 -gt 100MB } |
    Sort-Object WorkingSet64 -Descending |
    Select-Object Name, @{N='Memory(MB)'; E={[math]::Round($_.WorkingSet64/1MB,2)}} |
    Format-Table -AutoSize

# Parallel processing
$servers = @('srv1', 'srv2', 'srv3')
$servers | ForEach-Object -Parallel {
    Test-Connection -ComputerName $_ -Count 1 -Quiet
} -ThrottleLimit 5

Windows Management

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# Service management
Get-Service -Name 'MyService' | Restart-Service -Force
New-Service -Name 'MyApp' -BinaryPathName 'C:\app\myapp.exe' -StartupType Automatic

# Registry operations
Get-ItemProperty -Path 'HKLM:\SOFTWARE\MyApp' -Name 'Version'
Set-ItemProperty -Path 'HKLM:\SOFTWARE\MyApp' -Name 'Version' -Value '2.0'

# Scheduled tasks
$trigger = New-ScheduledTaskTrigger -Daily -At '2:00AM'
$action = New-ScheduledTaskAction -Execute 'powershell.exe' -Argument '-File C:\scripts\backup.ps1'
Register-ScheduledTask -TaskName 'NightlyBackup' -Trigger $trigger -Action $action

Configuration

Parameter	Type	Default	Description
PSVersion	string	"7.0"	Minimum PowerShell version
ErrorActionPreference	string	"Stop"	Error handling: Stop, Continue, SilentlyContinue
ExecutionPolicy	string	"RemoteSigned"	Script execution policy
OutputEncoding	string	"UTF8"	Output text encoding
ProgressPreference	string	"SilentlyContinue"	Progress bar display

Best Practices

1. Always use $ErrorActionPreference = 'Stop' — by default, PowerShell continues after non-terminating errors; Stop makes all errors halt execution like other languages expect.

2. Use [CmdletBinding()] and named parameters — this enables -Verbose, -Debug, and -ErrorAction on your functions, and validates parameter input automatically.

3. Wrap executable calls with the call operator & — use & program.exe --arg instead of just program.exe --arg; the call operator handles paths with spaces and ensures proper execution.

4. Use Test-Path before file operations — always check if paths exist before reading, writing, or deleting; PowerShell file errors can be cryptic without pre-validation.

5. Use try/catch/finally for all critical operations — catch specific exception types when possible: catch [System.IO.IOException] is more precise than a generic catch.

Common Issues

Scripts won't run due to execution policy — Run Set-ExecutionPolicy RemoteSigned -Scope CurrentUser to allow local scripts. Don't use Unrestricted in production as it allows all scripts.

Comparison operators don't work as expected — PowerShell uses -eq, -ne, -gt, -lt instead of ==, !=, >, <. The familiar operators are for redirection and will create files instead of comparing.

String variables don't expand in single quotes — Use double quotes "Hello $name" for variable expansion; single quotes 'Hello $name' are literal strings. This is the opposite of some other languages.