Set-PathVariable.ps1

<#
.SYNOPSIS
	Modify the PATH environment variable.
.DESCRIPTION
	Set-PathVariable allows you to add or remove paths to your PATH variable at the specified scope with logic that prevents duplicates.
.PARAMETER AddPath
    A path that you wish to add. Can be specified with or without a trailing slash.
.PARAMETER RemovePath
    A path that you wish to remove. Can be specified with or without a trailing slash.
.PARAMETER Scope
	The scope of the variable to edit. Either Process, User, or Machine.

    If you specify Machine, you must be running as administrator.
.EXAMPLE
	Set-PathVariable -AddPath C:\tmp\bin -RemovePath C:\path\java

    This will add the C:\tmp\bin path and remove the C:\path\java path. The Scope will be set to Process, which is the default.
.INPUTS
	
.OUTPUTS
	
.NOTES
	Author: ThePoShWolf
.LINK
	
#>
Function Set-PathVariable {
    param (
        [string]$AddPath,
        [string]$RemovePath,
        [ValidateSet('Process', 'User', 'Machine')]
        [string]$Scope = 'Process'
    )
    $regexPaths = @()
    if ($PSBoundParameters.Keys -contains 'AddPath') {
        $regexPaths += [regex]::Escape($AddPath)
    }

    if ($PSBoundParameters.Keys -contains 'RemovePath') {
        $regexPaths += [regex]::Escape($RemovePath)
    }
    
    $arrPath = [System.Environment]::GetEnvironmentVariable('PATH', $Scope) -split ';'
    foreach ($path in $regexPaths) {
        $arrPath = $arrPath | Where-Object { $_ -notMatch "^$path\\?" }
    }
    $value = ($arrPath + $addPath) -join ';'
    [System.Environment]::SetEnvironmentVariable('PATH', $value, $Scope)
}