Public/Environment/Get-WindowsEnvironmentVariable.ps1
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using namespace Microsoft.Win32 <# .SYNOPSIS Gets an Environment Variable. .DESCRIPTION This will will get an environment variable based on the variable name and scope while accounting whether to expand the variable or not (e.g.: `%TEMP%`-> `C:\User\Username\AppData\Local\Temp`). .NOTES This helper reduces the number of lines one would have to write to get environment variables, mainly when not expanding the variables is a must. .PARAMETER Name The environment variable you want to get the value from. .PARAMETER Scope The environment variable target scope. This is `Process`, `User`, or `Machine`. .PARAMETER PreserveVariables A switch parameter stating whether you want to expand the variables or not. Defaults to false. .PARAMETER IgnoredArguments Allows splatting with arguments that do not apply. Do not use directly. .EXAMPLE Get-WindowsEnvironmentVariable -Name 'TEMP' -Scope User -PreserveVariables .EXAMPLE Get-WindowsEnvironmentVariable -Name 'PATH' -Scope Machine #> function Get-WindowsEnvironmentVariable { [CmdletBinding()] [OutputType([string])] param ( [Parameter(Mandatory = $true)] [string] $Name, [Parameter(Mandatory = $true)] [System.EnvironmentVariableTarget] $Scope ) [string] $MACHINE_REG = "SYSTEM\CurrentControlSet\Control\Session Manager\Environment\"; [string] $USER_REG = "Environment"; switch ($Scope) { 'Machine' { [RegistryKey] $RegKey = [Registry]::LocalMachine.OpenSubKey($MACHINE_REG) } 'User' { [RegistryKey] $RegKey = [Registry]::CurrentUser.OpenSubKey($USER_REG) } 'Process' { return [Environment]::GetEnvironmentVariable($Name, $Scope) } default { throw "Unknown environment variable scope: $Scope" } } [string] $envValue = '' if ($null -ne $RegKey) { try { # Some versions of Windows do not have HKCU:\Environment $envValue = $RegKey.GetValue($Name, [string]::Empty) } catch { Write-Error "Unable to retrieve the $Name environment variable." } finally { $RegKey.Close() } } if ([String]::IsNullOrEmpty($envValue)) { $envValue = [Environment]::GetEnvironmentVariable($Name, $Scope) } return $envValue } |