无需重启更改系统环境变量

优势：
setx克服1024个字符的限制

PowerShell脚本

$newPath = 'f:\common tools\git\bin;f:\common tools\python\app;f:\common tools\python\app\scripts;f:\common tools\ruby\bin;f:\masm32\bin;F:\Borland\BCC55\Bin'
$oldPath = [Environment]::GetEnvironmentVariable('path', 'machine');
[Environment]::SetEnvironmentVariable('path2', "$($newPath);$($oldPath)",'Machine');

参考：
https://qastack.cn/superuser/387619/overcoming-the-1024-character-limit-with-setx