https://github.com/ThePoShWolf/Utilities/blob/master/Misc/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.
Set-PathVariable -AddPath "C:\tmp abc\bin" -Scope Machine
Set-PathVariable -RemovePath C:\tmp\bin -Scope Machine
Set-PathVariable -RemovePath "C:\tmp abc\bin" -Scope Machine
.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)
}