如果你的路径包含在会话开始时没有定义的环境变量，你也需要展开它们:

$env:Path = [System.Environment]::ExpandEnvironmentVariables([System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User"))

对我来说，这在安装NVM后很有用，NVM定义并添加了%NVM_HOME%到路径。

为了得出它的逻辑结论，你可以使用这个递归函数来展开:

function Expand-EnvironmentVariablesRecursively($unexpanded) {
    $previous = ''
    $expanded = $unexpanded
    while($previous -ne $expanded) {
        $previous = $expanded
        $expanded = [System.Environment]::ExpandEnvironmentVariables($previous)
    }
    return $expanded
}

然后使用:

$env:Path = Expand-EnvironmentVariablesRecursively([System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User"))

我已经打开了一个问题，将这个解决方案添加到refreshenv from Chocolatey。

如果你的路径包含在会话开始时没有定义的环境变量，你也需要展开它们:

$env:Path = [System.Environment]::ExpandEnvironmentVariables([System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User"))

对我来说，这在安装NVM后很有用，NVM定义并添加了%NVM_HOME%到路径。

为了得出它的逻辑结论，你可以使用这个递归函数来展开:

function Expand-EnvironmentVariablesRecursively($unexpanded) {
    $previous = ''
    $expanded = $unexpanded
    while($previous -ne $expanded) {
        $previous = $expanded
        $expanded = [System.Environment]::ExpandEnvironmentVariables($previous)
    }
    return $expanded
}

然后使用:

$env:Path = Expand-EnvironmentVariablesRecursively([System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User"))

我已经打开了一个问题，将这个解决方案添加到refreshenv from Chocolatey。

最简单的方法就是使用Chocolatey(免费软件)。它适用于CMD和PowerShell。然后你将能够用一个简单的命令重新加载PATH(变量扩展):

refreshenv

从cmd安装(需要管理员权限):

@"%SystemRoot%\System32\WindowsPowerShell\v1.0\powershell.exe" -NoProfile -InputFormat None -ExecutionPolicy Bypass -Command "iex ((New-Object System.Net.WebClient).DownloadString('https://chocolatey.org/install.ps1'))" && SET "PATH=%PATH%;%ALLUSERSPROFILE%\chocolatey\bin"

使用示例:

> SET JAVA_HOME=c:/java/jdk6
> SET PATH=%JAVA_HOME%/bin
> ECHO %PATH%
c:/java/jdk6/bin

> SET JAVA_HOME=c:/java/jdk8
> refreshenv
Refreshing environment variables from registry for cmd.exe. Please wait...Finished..
> echo %PATH%
c:/java/jdk8/bin

让我们来看看罗伯的评论:

$env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path","User") 

根据pen的回答，下面是一个PowerShell函数:

function refresh-path {
    $env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine") +
                ";" +
                [System.Environment]::GetEnvironmentVariable("Path","User")
}

然后调用refresh-path。

尝试获取机器路径并将其分配给会话的路径。

$env:Path = [System.Environment]::GetEnvironmentVariable("Path","Machine")