Tidy up Windows PATH environment variable

path-cleanup.ps

# For demostration purposes only. Use at your own risk.

$OriginalMachinePath = [Environment]::GetEnvironmentVariable('Path','Machine')
$UniqueMachinePaths = ($OriginalMachinePath -split ';') | ForEach-Object {
    $_.Trim([Char]'\',[Char]'/')
} | Sort-Object -Unique
$UniqueMachinePath = [string]::Join(";",$UniqueMachinePaths).Trim([Char]';')
$OriginalMachinePath > ".\original_machine_path.txt"
$UniqueMachinePath > ".\unique_machine_path.txt"

$OriginalUserPath = [Environment]::GetEnvironmentVariable('Path','User')
$UniqueUserPaths = ($OriginalUserPath -split ';') | ForEach-Object {
    $_.Trim([Char]'\',[Char]'/')
} | Sort-Object -Unique
$UniqueUserPath = [string]::Join(";",$UniqueMachinePaths).Trim([Char]';')
$FilteredUserPaths = $UniqueUserPaths.Where({-Not ($UniqueMachinePaths.contains($_))})
$FilteredUserPath = [string]::Join(";",$FilteredUserPaths).Trim([Char]';')
$OriginalUserPath > ".\original_user_path.txt"
$UniqueUserPath > ".\unique_user_path.txt"
$FilteredUserPath > ".\filtered_user_path.txt"

# Use caution and at your own risk.
Write-Output $FilteredUserPath # It's not empty... right?
[Environment]::SetEnvironmentVariable('Path', $FilteredUserPath,'User')

# You need to be running an administrator to clean up the machine path.
# Also double check anything, don't trust anything you didn't write, etc, etc o_o
Write-Output $UniqueMachinePath # It's not empty... right?
[Environment]::SetEnvironmentVariable('Path', $UniqueMachinePath,'Machine')