PowerShellFunctions

Presented byMike Pfeiffer

http://www.AZPoSH.com

AgendaPowerShell Functions

What is a PowerShell Function?Structure of a PowerShell FunctionFunction GuidelinesInput ParametersOutputScopeFunctions in the PipelineBegin, Process and End BlocksParameter AttributesComment Based Help

What is a PowerShell Function?Think of it as a block of code that behaves as

a cmdletCan be loaded from your profile, dot sourced

via a script, or imported from a moduleCan be called or defined in another function

or script

Structure of a PowerShell Function

Function GuidelinesMust be defined before they are calledCall functions without parenthesis or

commas:Get-MyStuff –Param1 $value1 –Param2 $value2Get-MyStuff $value1 $value2

Input ParametersThe $args variableNamed and positional parametersParameter type constraintsInitializing parameters with default valuesThe switch parameter

OutputWrite-Host is for writing to the consoleUse Write-Output to return function outputDon’t use the Return keyword to return

output

ScopeFunctions have internal scopeDon’t use or modify variables from parent

scopeConsider using default values for internal

variables

Functions in the PipelineThe $input variableFilters

Begin, Process and End Blocks

Parameter Attributes

Parameter Attribute Declaration (MSDN): http://bit.ly/bzGu34

Comment Based Help

ResourcesGet-Help About_FunctionsGet-Help About_Functions_AdvancedGet-Help About_Comment_Based_HelpPowerShell in Action

http://manning.com/payette2/PowerGUI PowerShell v2 Snippets

http://bit.ly/azDkJG

Thank You!