Public/Get-EnvironmentVariable.ps1
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function Get-EnvironmentVariable { <# .SYNOPSIS Retrieves the value of an environment variable. .DESCRIPTION The Get-EnvironmentVariable function retrieves the value of the specified environment variable or displays all environment variables. .PARAMETER Name The name of the environment variable to retrieve. .EXAMPLE Get-EnvironmentVariable -Name "PATH" Retrieves the value of the "PATH" environment variable. .NOTES Author: Sam Erde Version: 0.0.2 Modified: 2024/10/12 Variable names are case-sensitive on Linux and macOS, but not on Windows. Why is 'Target' used by .NET instead of the familiar 'Scope' parameter name? @IISResetMe (Mathias R. Jessen) explains: "Scope" would imply some sort of integrated hierarchy of env variables - that's not really the case. Target=Process translates to kernel32!GetEnvironmentVariable (which then in turn reads the PEB from the calling process), whereas Target={User,Machine} causes a registry lookup against environment data in either HKCU or HKLM. The relevant sources for the User and Machine targets are in the registry at: - HKEY_CURRENT_USER\Environment - HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment See more at <https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_environment_variables>. #> [Alias('gev')] [CmdletBinding(HelpUri = 'https://day3bits.com/PSPreworkout/Get-EnvironmentVariable')] [OutputType('System.String')] param ( # The name of the environment variable to retrieve. If not specified, all environment variables are returned. [Parameter(Position = 0)] [string]$Name, # The target of the environment variable to retrieve. Defaults to User. (Process, User, or Machine) [Parameter(Position = 1)] [System.EnvironmentVariableTarget] $Target = [System.EnvironmentVariableTarget]::User, # Switch to show environment variables in all target scopes. [Parameter()] [switch] $All ) # If a variable name was specified, get that environment variable from the default target or specified target. if ( $PSBoundParameters.Keys.Contains('Name') ) { [Environment]::GetEnvironmentVariable($Name, $Target) } elseif (-not $PSBoundParameters.Keys.Contains('All') ) { [Environment]::GetEnvironmentVariables() } # If only the target is specified, get all environment variables from that target. if ( $PSBoundParameters.Keys.Contains('Target') -and -not $PSBoundParameters.ContainsKey('Name') ) { [System.Environment]::GetEnvironmentVariables([System.EnvironmentVariableTarget]::$Target) } # Get all environment variables from all targets. # To Do: Get the specified variable name from all targets if a name and -All are specified. if ($All) { Write-Output 'Process Environment Variables:' [Environment]::GetEnvironmentVariables([System.EnvironmentVariableTarget]::Process) Write-Output 'User Environment Variables:' [Environment]::GetEnvironmentVariables([System.EnvironmentVariableTarget]::User) Write-Output 'Machine Environment Variables:' [Environment]::GetEnvironmentVariables([System.EnvironmentVariableTarget]::Machine) } } |