Powershell 如何在不扩展令牌的情况下获取PATH环境变量的值?
我正在编写一个PowerShell脚本,将文件夹名称转换为PATH环境变量中的短名称,并保存更改。它可以正确地用于显式路径,但它会扩展标记,因此当我保存更改时,标记将替换为显式路径。我想保留这些代币 例如,如果我的路径是:Powershell 如何在不扩展令牌的情况下获取PATH环境变量的值?,powershell,environment-variables,Powershell,Environment Variables,我正在编写一个PowerShell脚本,将文件夹名称转换为PATH环境变量中的短名称,并保存更改。它可以正确地用于显式路径,但它会扩展标记,因此当我保存更改时,标记将替换为显式路径。我想保留这些代币 例如,如果我的路径是:%SystemRoot%;%SystemRoot%\system32;C:\Program Files\TortoiseSVN\bin;C:\ProgramData\Chocolate\bin 我想要这个结果:%SystemRoot%;%SystemRoot%\system32
%SystemRoot%;%SystemRoot%\system32;C:\Program Files\TortoiseSVN\bin;C:\ProgramData\Chocolate\bin
我想要这个结果:%SystemRoot%;%SystemRoot%\system32;C:\PROGRA~1\TORTOI~1\bin;C:\PROGRA~3\CHOCOL~1\bin
但我得到的却是:C:\Windows;C:\Windows\system32;C:\PROGRA~1\TORTOI~1\bin;C:\PROGRA~3\CHOCOL~1\bin
下面是说明问题的完整脚本
# get the current path.
# I ended up not using either of these approaches because they appear to
# be contextual; on my system, at least, they include paths that aren't
# seen when I view the PATH value from the System Properties -> Environment
# Variables dialog box.
$current_path = $env:Path
$current_path = [System.Environment]::GetEnvironmentVariable("Path")
# Instead, I get the PATH value directly from the registry, like so:
$current_path = (Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment' -Name Path).Path
# The problem is that PowerShell expands the tokens even when reading from the
# registry, so I can't detect the tokens and ignore them. What I really want
# is just the literal string value, with no token evaluation.
# Here's a sample value; this is what I see in regedt32 and the system dialogs,
# but it's not what I get from the line above.
$current_path = '%SystemRoot%;%SystemRoot%\system32;C:\Program Files\TortoiseSVN\bin;C:\ProgramData\chocolatey\bin'
$new_path = ''
# the FileSystemObject has a method to convert the path using short names for the folders.
$fso = New-Object -ComObject Scripting.FileSystemObject
# Individual paths are delimited by a semicolon. Skip paths with tokens,
# and preserve trailing slashes in each path.
$current_path.Split(';') |
ForEach-Object {
if ($_.StartsWith('%'))
{ $_ }
elseif ($_.EndsWith('\'))
{ "$($fso.GetFolder($_).ShortPath)\" }
else
{ "$($fso.GetFolder($_).ShortPath)" }
} |
ForEach-Object { $new_path += "$_;" }
# remove the extra semicolon from the end the new PATH.
$new_path = $new_path.TrimEnd(";")
"Current PATH length: $($current_path.Length)"
"New PATH length: $($new_path.Length)"
$new_path
# commented out so you don't accidentally update your path if you try out this script
#[System.Environment]::SetEnvironmentVariable("Path", $new_path, "Machine")
如果我可以从注册表中获取文本字符串值,似乎应该很容易,但到目前为止,我还没有弄清楚如何做到这一点。这不是PowerShell本身,而是底层Windows注册表的一个“功能”。Path变量的类型为REG_EXPAND_SZ,可在检索时自动展开环境变量。我认为使用内置cmdlet无法解决这个问题,但可以使用.NET
Microsoft.Win32.Registry
API。将RegistryKey.GetValue
重载与RegistryValueOptions.DoNotExpandEnvironmentNames一起使用:
$regKey = [Microsoft.Win32.Registry]::LocalMachine.OpenSubKey('SYSTEM\CurrentControlSet\Control\Session Manager\Environment', $true)
$regKey.GetValue('Path', $null, "DoNotExpandEnvironmentNames")
保存变量时,使用SetValue
和RegistryValueKind.ExpandString
的重载以正确的类型保存变量:
$regKey.SetValue("Path", $new_path, "ExpandString")
不使用.NET[Microsoft.Win32.Registry]
键入:用户和系统路径条目的一行程序
(Get-Item -path "HKCU:\Environment" ).GetValue('Path', '', 'DoNotExpandEnvironmentNames')
(Get-Item -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" ).
GetValue('Path', '', 'DoNotExpandEnvironmentNames')
我必须在调用OpenSubkey()时添加一个参数,比如soOpenSubkey('SYSTEM\CurrentControlSet\Control\Session Manager\Environment','ReadWriteSubTree')
,然后它才允许我使用SetValue()写回注册表,但除此之外,这正是我想要的。非常感谢@Matt Oh yea默认情况下注册表项不可写。您需要调用该重载或接受bool的重载(如在我的编辑中)。使用您的答案创建了一个powershell脚本,该脚本自动等幂添加未扩展路径: