powershell

# PowerShell ## What I Do I am PowerShell, Microsoft's command-line shell and scripting language built on .NET. I provide powerful automation capabilities across Windows, Linux, and macOS. I use a verb-noun naming convention for discoverable commands. I pipeline objects between commands, not text. I offer advanced scripting features including functions, modules, classes, and workflows. I integrate with COM, WMI, .NET, and REST APIs. My Just Enough Administration (JEA) enables role-based administration. I support Desired State Configuration (DSC) for declarative configuration management. I'm essential for Windows Server automation and cloud management with Azure PowerShell. ## When to Use Me - Windows Server administration - Active Directory management - Cloud automation (Azure, AWS, GCP) - Exchange/SharePoint administration - Configuration management with DSC - Log analysis and reporting - CI/CD pipeline scripting - Task automation and scheduling - Exchange data protection ## Core Concepts **Cmdlets**: Small, single-purpose commands following Verb-Noun convention. **Pipeline**: Passing objects between commands for chained operations. **Providers**: Access to different data stores (filesystem, registry, certificates). **Modules**: Bundled cmdlets for specific functionality. **DSC**: Desired State Configuration for declarative infrastructure. **Remote PowerShell**: WS-Management for remote execution. **Classes**: Custom types with properties and methods. **Jobs**: Background tasks for parallel execution. ## Code Examples ### Example 1: Advanced Function Template ```powershell function Invoke-SystemHealthCheck { <# .SYNOPSIS Performs comprehensive system health check .DESCRIPTION This function checks various system components and returns a health status report .PARAMETER ComputerName Target computer name(s) .PARAMETER Timeout Connection timeout in seconds .PARAMETER IncludeLogs Include event log analysis .EXAMPLE Invoke-SystemHealthCheck -ComputerName 'SERVER01' .EXAMPLE Invoke-SystemHealthCheck -ComputerName 'SERVER01','SERVER02' -IncludeLogs #> [CmdletBinding( SupportsShouldProcess=$true, ConfirmImpact='Low' )] param( [Parameter( Mandatory=$false, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true )] [Alias('CN','Name','Server')] [string[]]$ComputerName = $env:COMPUTERNAME, [Parameter()] [int]$Timeout = 30, [Parameter()] [switch]$IncludeLogs, [Parameter()] [string]$OutputPath ) begin { $results = @() $stopwatch = [System.Diagnostics.Stopwatch]::StartNew() Write-Verbose "Starting health check at $(Get-Date)" } process { foreach ($computer in $ComputerName) { Write-Information "Processing $computer" -InformationAction Continue if ($PSCmdlet.ShouldProcess($computer, "Check system health")) { $computerResults = @{ ComputerName = $computer CheckTime = Get-Date Checks = @{} } # Check connectivity $computerResults.Checks['Connectivity'] = @{ Status = Test-Connection -ComputerName $computer -Count 1 -Quiet Latency = (Measure-Command { Test-Connection -ComputerName $computer -Count 1 }).Milliseconds } # Check services if ($computer -eq $env:COMPUTERNAME -or (Test-WSMan $computer -ErrorAction SilentlyContinue)) { $criticalServices = @('WinRM','Dhcp','Dns') $computerResults.Checks['Services'] = foreach ($service in $criticalServices) { $svc = Get-Service -Name $service -ComputerName $computer -ErrorAction SilentlyContinue @{ Name = $service Status = $svc?.Status ?? 'Unknown' StartType = (Get-CimInstance -ClassName Win32_Service ` -Filter "Name='$service'" ` -ComputerName $computer -ErrorAction SilentlyContinue)?.StartMode } } # Check disk space $computerResults.Checks['Disks'] = Get-CimInstance -ClassName Win32_LogicalDisk ` -ComputerName $computer -ErrorAction SilentlyContinue | Where-Object {$_.DriveType -eq 3} | ForEach-Object { @{ Drive = $_.DeviceID PercentFree = [math]::Round(($_.FreeSpace / $_.Size) * 100, 2) Status = if ($_.FreeSpace / $_.Size -lt 0.1) { 'Critical' } elseif ($_.FreeSpace / $_.Size -lt 0.2) { 'Warning' } else { 'Healthy' } } } } # Event logs if ($IncludeLogs) { $computerResults.Checks['EventLogs'] = @{ Errors = (Get-EventLog -LogName System -EntryType Error ` -After (Get-Date).AddHours(-24) -ComputerName $computer -ErrorAction SilentlyContinue).Count Warnings = (Get-EventLog -LogName System -EntryType Warning ` -After (Get-Date).AddHours(-24) -ComputerName $computer -ErrorAction SilentlyContinue).Count } } $results += [PSCustomObject]$computerResults } } } end { $stopwatch.Stop() Write-Verbose "Health check completed in $($stopwatch.Elapsed.TotalSeconds) seconds" # Output results $results | ForEach-Object { [PSCustomObject]@{ ComputerName = $_.ComputerName OverallStatus = if ($_.Checks.Values.Status -contains 'Critical') { 'Critical' } elseif ($_.Checks.Values.Status -contains 'Warning') { 'Warning' } else { 'Healthy' } Details = $_.Checks } } # Export to file if ($OutputPath) { $results | Export-Clixml -Path $OutputPath -Force Write-Verbose "Results exported to $OutputPath" } } } ``` ### Example 2: DSC Configuration ```powershell configuration WebServerConfig { param( [Parameter(Mandatory=$true)] [string[]]$ComputerName, [Parameter(Mandatory=$true)] [string]$WebSiteName, [Parameter(Mandatory=$true)] [string]$PhysicalPath ) Import-DscResource -ModuleName PSDesiredStateConfiguration Import-DscResource -ModuleName xWebAdministration node $ComputerName { # Install Web Server role WindowsFeature WebServer { Ensure = 'Present' Name = 'Web-Server' } # Install management tools WindowsFeature WebMgmtTools { Ensure = 'Present' Name = 'Web-Mgmt-Tools' DependsOn = '[WindowsFeature]WebServer' } # Create application pool xWebAppPool AppPool { Ensure = 'Present' Name = $WebSiteName State = 'Started' ManagedRuntimeVersion = 'v4.0' IdentityType = 'ApplicationPoolIdentity' DependsOn = '[WindowsFeature]WebMgmtTools' } # Create website xWebsite WebSite { Ensure = 'Present' Name = $WebSiteName State = 'Started' PhysicalPath = $PhysicalPath ApplicationPool = $WebSiteName BindingInfo = MSFT_xWebBindingInformation { Protocol = 'http' Port = 80 } DependsOn = '[xWebAppPool]AppPool' } # Configure authentication xWebConfigProperty Authentication { WebsitePath = "IIS:\Sites\$WebSiteName" Filter = 'system.webServer/security/authentication/anonymousAuthentication' PropertyName = 'Enabled' Value = $false DependsOn = '[xWebsite]WebSite' } # Ensure SSL required xWebConfigProperty RequireSSL { WebsitePath = "IIS:\Sites\$WebSiteName" Filter = 'system.webServer/security/access' PropertyName = 'sslFlags' Value = 'Ssl' DependsOn = '[xWebsite]WebSite' } # Configure logging xWebsiteLogging Logging { Ensure = 'Present' Name = $WebSiteName LogDirectory = 'C:\inetpub\logs\LogFiles' LogFlags = @('Date','Time','ServerIP','Method','UriStem','Status','TimeTaken') DependsOn = '[xWebsite]WebSite' } # Windows Firewall Firewall AddFirewallRule { Ensure = 'Present' Name = "IIS-WebTraffic-HTTP-In" DisplayName = "IIS HTTP Traffic" Direction = 'Inbound' Protocol = 'tcp' LocalPort = 80 Action = 'Allow' Enabled = 'True' } } } # Generate MOF files WebServerConfig -ComputerName @('WEB01','WEB02') ` -WebSiteName 'MyApplication' ` -PhysicalPath 'D:\Websites\MyApplication' # Apply configuration Start-DscConfiguration -Path .\WebServerConfig -Wait -Verbose -Force ``` ### Example 3: REST API Client ```powershell class APIClient { [string]$BaseUri [hashtable]$Headers [int]$Timeout [bool]$IgnoreSSL APIClient([string]$BaseUri, [int]$Timeout = 30) { $this.BaseUri = $BaseUri $this.Timeout = $Timeout $this.Headers = @{ 'Content-Type' = 'application/json' 'Accept' = 'application/json' } } [void] SetBearerToken([string]$Token) { $this.Headers['Authorization'] = "Bearer $Token" } [object] Get([string]$Endpoint, [hashtable]$QueryParams = @{}) { $uri = "$($this.BaseUri)/$Endpoint" if ($QueryParams.Count -gt 0) { $uri += '?' + ($QueryParams.GetEnumerator() | ForEach-Object { "$($_.Key)=$([System.Web.HttpUtility]::UrlEncode($_.Value))" }) -join '&' } $params = @{ Uri = $uri Method = 'GET' Headers = $this.Headers Timeout = $this.Timeout } return $this.Invoke-RestMethod @params } [object] Post([string]$Endpoint, [object]$Body) { $uri = "$($this.BaseUri)/$Endpoint" $params = @{ Uri = $uri Method = 'POST' Headers = $this.Headers Body = $Body | ConvertTo-Json -Depth 10 Timeout = $this.Timeout } return $this.Invoke-RestMethod @params } [object] Put([string]$Endpoint, [object]$Body) { $uri = "$($this.BaseUri)/$Endpoint" $params = @{ Uri = $uri Method = 'PUT' Headers = $this.Headers Body = $Body | ConvertTo-Json -Depth 10 Timeout = $this.Timeout } return $this.Invoke-RestMethod @params } [object] Patch([string]$Endpoint, [object]$Body) { $uri = "$($this.BaseUri)/$Endpoint" $params = @{ Uri = $uri Method = 'PATCH' Headers = $this.Headers Body = $Body | ConvertTo-Json -Depth 10 Timeout = $this.Timeout } return $this.Invoke-RestMethod @params } [void] Delete([string]$Endpoint) { $uri = "$($this.BaseUri)/$Endpoint" $params = @{ Uri = $uri Method = 'DELETE' Headers = $this.Headers Timeout = $this.Timeout } $null = Invoke-RestMethod @params } } # Usage example $api = [APIClient]::new('https://api.example.com/v1') $api.SetBearerToken('your-token-here') # GET request $users = $api.Get('users') # POST request $newUser = @{ name = 'John Doe' email = 'john@example.com' role = 'admin' } $created = $api.Post('users', $newUser) ``` ### Example 4: Parallel Processing with Jobs ```powershell function Invoke-ParallelProcessing { <# .SYNOPSIS Process items in parallel using jobs #> param( [Parameter(Mandatory=$true)] [array]$InputObject, [Parameter(Mandatory=$true)] [scriptblock]$ScriptBlock, [Parameter()] [int]$ThrottleLimit = 5, [Parameter()] [string]$PropertyName ) $results = @() $jobs = @() foreach ($item in $InputObject) { $job = @{ ScriptBlock = $ScriptBlock InputObject = $item } if ($PropertyName) { $job['Name'] = $item.$PropertyName } $jobs += $job # Start job when throttle limit not reached if ($jobs.Count -ge $ThrottleLimit) { $results += Receive-Job -Job ($jobs | Start-Job -ScriptBlock $ScriptBlock) -ErrorAction Continue $jobs = @() } } # Process remaining jobs if ($jobs.Count -gt 0) { $results += Receive-Job -Job ($jobs | Start-Job -ScriptBlock $ScriptBlock) -ErrorAction Continue } return $results } # Example usage - process multiple servers $servers = @('SERVER01','SERVER02','SERVER03','SERVER04','SERVER05') $script = { param($server) Get-CimInstance -ComputerName $server -ClassName Win32_OperatingSystem | Select-Object @{N='Server';E={$server}}, Caption, Version } $results = Invoke-ParallelProcessing -InputObject $servers -ScriptBlock $script -ThrottleLimit 3 ``` ## Best Practices