Add new entry to the path environment variable

addEntry.ps1

# source: 
# https://stackoverflow.com/questions/17240725/setx-doesnt-append-path-to-system-path-variable/17247259

$new_entry = 'd:\app'

$old_path = [Environment]::GetEnvironmentVariable('path', 'machine');
$new_path = $old_path + ';' + $new_entry
[Environment]::SetEnvironmentVariable('path', $new_path,'Machine');