如何在 PowerShell 中找到部分路径的潜在源环境变量？
How can I find the potential source environment variable for a partial path in PowerShell?
我想编写一个将常规路径转换为包含环境变量的路径的函数：
例如：
C:\Windows\SomePath
转换为：
%Windir%\SomePath
我该怎么做，这可能吗？
这是我想要做的，但问题是，我需要检查字符串
所有可能的变量，有没有更自动的方法？这样就不需要 -replace 运算符
function Format-Path
{
param (
[parameter(Mandatory = $true)]
[string] $FilePath
)
if (![System.String]::IsNullOrEmpty($FilePath))
{
# Strip away quotations and ending backslash
$FilePath = $FilePath.Trim('"')
$FilePath = $FilePath.TrimEnd('\')
}
$FilePath = $FilePath -replace "C:\Windows", "%Windir%"
$FilePath = $FilePath -replace "C:\ProgramFiles", "%ProgramFiles%"
$FilePath = $FilePath -replace "C:\ProgramFiles (x86)", "%ProgramFiles (x86)%"
# ETC.. the list goes on..
return $FilePath
}
# test case
Format-Path '"C:\Windows\SomePath\"'
输出为：
%Windir%\SomePath
编辑：
无效的输入或错误的代码并不是真正的问题，因为最后 $Path 可以很容易地检查：
Test-Path -Path ([System.Environment]::ExpandEnvironmentVariables($FilePath))
这是我最终尝试将其自动化的结果：
function Format-Path {
param (
[string]$path
)
## Environmental variable list
$EV_Variables = ( gci env:* | Where-Object {$_.Name -notin "SystemDrive", "HomeDrive" -and $_.Value -notmatch ";"} | sort-object name )
## Compare string
while ($EV_Variables.Value -like $path) {
foreach ($EC in $EV_Variables) {
if ( $path -like "*$($EC.value)*") {
$path = $path.Replace($EC.Value, "%$($EC.Name)%")
}
}
}
$path
}
Format-Path "C:\Program Files (x86)\Nmap\nmap.exe"
Format-Path "C:\Windows"
Format-Path "C:\Program Files"
Format-Path "C:\Program Files (x86)"
哪个returns:
%nmap%
%SystemRoot%
%ProgramFiles%
%ProgramFiles% (x%NUMBER_OF_PROCESSORS%%PROCESSOR_LEVEL%)
我在一些环境变量上对此进行了测试，它对大多数环境变量都有效，但围绕某些环境变量存在一些问题，例如上面显示的 %NUMBER_OF_PROCESSORS%，但我确定您可以将它们从变量列表中排除。
谢谢大家的建议，我看到 Owain Esau 已经 post 编辑了问题
我也在研究解决方案。
如果我不post我得出的结果可能是个错误:
function Format-Path
{
param (
[parameter(Mandatory = $true)]
[string] $FilePath
)
$SearchString = Split-Path -Path $FilePath -Parent
$Variables = @(Get-ChildItem Env:) | Sort-Object -Descending { $_.Value.length }
foreach ($Value in $Variables.Value)
{
if ($Value -like "*$SearchString")
{
$Replacement = "%" + @(($Variables | Where-Object { $_.Value -eq $Value} ).Name)[0] + "%"
return $FilePath.Replace($SearchString, $Replacement)
}
}
}
Format-Path "C:\Windows\SomePath"
Format-Path "C:\Program Files (x86)\SomePath"
Format-Path "C:\Program Files\SomePath"
Format-Path "C:\ProgramData\SomePath"
# does not work for %SystemDrive%
Format-Path "C:\SomePath"
输出：
%SystemRoot%\SomePath
%ProgramFiles(x86)%\SomePath
%ProgramFiles%\SomePath
%ProgramData%\SomePath
除 %SystemDrive% 需要进一步改进外，此方法有效。
我会留下这个问题以供改进。
下面的代码是我对此的看法。路径和反斜杠操作有一些特殊性，所以我试图在评论中解释所有内容。
有一个关键点，那就是 无限字符串搜索，例如 -replace、-like、.Contains() 等执行的搜索，并且可以当一个变量路径的值是另一个变量路径或目录路径的子字符串时，会产生不良结果。例如，给定 %ProgramFiles% (C:\Program Files) 和 %ProgramFiles(x86)% (C:\Program Files (x86))，路径 C:\Program Files (x86)\Test 可以转换为 %ProgramFiles% (x86)\Test 而不是 %ProgramFiles(x86)%\Test 如果 %ProgramFiles% 刚好在 %ProgramFiles(x86)% 之前测试。
解决方案是只比较一个变量的路径和一个完整的路径段。也就是说，在路径 C:\Program Files (x86)\Test 的情况下，比较会像这样...
- 测试与原始路径是否相等
C:\Program Files (x86)\Test。没有匹配的变量。
- 测试与父路径是否相等
C:\Program Files (x86)。 %ProgramFiles(x86)% 匹配。没有进一步的祖先路径（即 C:）被测试。
%ProgramFiles% 永远不会匹配，因为未测试部分路径 C:\Program Files。
通过仅针对完整路径段进行测试，变量与候选路径的比较顺序无关紧要。
New-Variable -Name 'VariablesToSubstitute' -Option Constant -Value @(
# Hard-code system variables that contain machine-wide paths
'CommonProgramFiles',
'CommonProgramFiles(x86)',
'ComSpec',
'ProgramData', # Alternatively: ALLUSERSPROFILE
'ProgramFiles',
'ProgramFiles(x86)',
'SystemDrive'
'SystemRoot' # Alternatively: WinDir
'MyDirectoryWithoutSlash' # Defined below
'MyDirectoryWithSlash' # Defined below
);
function Format-Path
{
param (
[parameter(Mandatory = $true)]
[string] $FilePath
)
if (![System.String]::IsNullOrEmpty($FilePath))
{
# Strip away quotations
$FilePath = $FilePath.Trim('"')
# Leave trailing slashes intact so variables with a trailing slash will match
#$FilePath = $FilePath.TrimEnd('\')
}
# Initialize this once, but only after the test code has started
if ($null -eq $script:pathVariables)
{
$script:pathVariables = $VariablesToSubstitute | ForEach-Object -Process {
$path = [Environment]::GetEnvironmentVariable($_)
if ($null -eq $path)
{
Write-Warning -Message "The environment variable ""$_"" is not defined."
}
else
{
return [PSCustomObject] @{
Name = $_
Path = $path
}
}
}
}
# Test against $FilePath and its ancestors until a match is found or the path is empty.
# Only comparing with complete path segments prevents performing partial substitutions
# (e.g. a path starting with %ProgramFiles(x86)% being substituted with %ProgramFiles%,
# or "C:\Windows.old" being transformed to "%SystemRoot%.old")
for ($filePathAncestorOrSelf = $FilePath;
-not [String]::IsNullOrEmpty($filePathAncestorOrSelf);
# Split-Path -Parent removes the trailing backslash on the result *unless* the result
# is a drive root. It'd be easier to normalize all paths without the backslash, but
# Split-Path throws an error if the input path is a drive letter with no slash, so
# normalize everything *with* the backslash and strip it off later.
$filePathAncestorOrSelf = EnsureTrailingBackslash (
# Protect against the case where $FilePath is a drive letter with no backslash
# We have to do this here because we want our initial path above to be
# exactly $FilePath, not (EnsureTrailingBackslash $FilePath).
Split-Path -Path (EnsureTrailingBackslash $filePathAncestorOrSelf) -Parent
)
)
{
# Test against $filePathAncestorOrSelf with and without a trailing backslash
foreach ($candidatePath in $filePathAncestorOrSelf, $filePathAncestorOrSelf.TrimEnd('\'))
{
foreach ($variable in $pathVariables)
{
if ($candidatePath -ieq $variable.Path)
{
$variableBasePath = "%$($variable.Name)%"
# The rest of the path after the variable's path
$pathRelativeToVariable = $FilePath.Substring($variable.Path.Length)
# Join-Path appends a trailing backslash if the child path is empty - we don't want that
if ([String]::IsNullOrEmpty($pathRelativeToVariable))
{
return $variableBasePath
}
# Join-Path will join the base and relative path with a slash,
# which we don't want if the variable path already ends with a slash
elseif ($variable.Path -like '*\')
{
return $variableBasePath + $pathRelativeToVariable
}
else
{
return Join-Path -Path $variableBasePath -ChildPath $pathRelativeToVariable
}
}
}
}
}
return $FilePath
}
function EnsureTrailingBackslash([String] $path)
{
return $(
# Keep an empty path unchanged so the for loop will terminate properly
if ([String]::IsNullOrEmpty($path) -or $path.EndsWith('\')) {
$path
} else {
"$path\"
}
)
}
使用这个测试代码...
$Env:MyDirectoryWithoutSlash = 'C:\My Directory'
$Env:MyDirectoryWithSlash = 'C:\My Directory\'
@'
X:
X:\Windows
X:\Windows\system32
X:\Windows\system32\cmd.exe
X:\Windows.old
X:\Windows.old\system32
X:\Windows.old\system32\cmd.exe
X:\Program Files\Test
X:\Program Files (x86)\Test
X:\Program Files (it's a trap!)\Test
X:\My Directory
X:\My Directory\Test
'@ -split "`r`n?" `
| ForEach-Object -Process {
# Test the path with the system drive letter
$_ -replace 'X:', $Env:SystemDrive
# Test the path with the non-system drive letter
$_
} | ForEach-Object -Process {
$path = $_.TrimEnd('\')
# Test the path without a trailing slash
$path
# If the path is a directory (determined by the
# absence of an extension in the last segment)...
if ([String]::IsNullOrEmpty([System.IO.Path]::GetExtension($path)))
{
# Test the path with a trailing slash
"$path\"
}
} | ForEach-Object -Process {
[PSCustomObject] @{
InputPath = $_
OutputPath = Format-Path $_
}
}
...我得到这个结果...
InputPath OutputPath
--------- ----------
C: %SystemDrive%
C:\ %SystemDrive%\
X: X:
X:\ X:\
C:\Windows %SystemRoot%
C:\Windows\ %SystemRoot%\
X:\Windows X:\Windows
X:\Windows\ X:\Windows\
C:\Windows\system32 %SystemRoot%\system32
C:\Windows\system32\ %SystemRoot%\system32\
X:\Windows\system32 X:\Windows\system32
X:\Windows\system32\ X:\Windows\system32\
C:\Windows\system32\cmd.exe %ComSpec%
X:\Windows\system32\cmd.exe X:\Windows\system32\cmd.exe
C:\Windows.old %SystemDrive%\Windows.old
X:\Windows.old X:\Windows.old
C:\Windows.old\system32 %SystemDrive%\Windows.old\system32
C:\Windows.old\system32\ %SystemDrive%\Windows.old\system32\
X:\Windows.old\system32 X:\Windows.old\system32
X:\Windows.old\system32\ X:\Windows.old\system32\
C:\Windows.old\system32\cmd.exe %SystemDrive%\Windows.old\system32\cmd.exe
X:\Windows.old\system32\cmd.exe X:\Windows.old\system32\cmd.exe
C:\Program Files\Test %ProgramFiles%\Test
C:\Program Files\Test\ %ProgramFiles%\Test\
X:\Program Files\Test X:\Program Files\Test
X:\Program Files\Test\ X:\Program Files\Test\
C:\Program Files (x86)\Test %ProgramFiles(x86)%\Test
C:\Program Files (x86)\Test\ %ProgramFiles(x86)%\Test\
X:\Program Files (x86)\Test X:\Program Files (x86)\Test
X:\Program Files (x86)\Test\ X:\Program Files (x86)\Test\
C:\Program Files (it's a trap!)\Test %SystemDrive%\Program Files (it's a trap!)\Test
C:\Program Files (it's a trap!)\Test\ %SystemDrive%\Program Files (it's a trap!)\Test\
X:\Program Files (it's a trap!)\Test X:\Program Files (it's a trap!)\Test
X:\Program Files (it's a trap!)\Test\ X:\Program Files (it's a trap!)\Test\
C:\My Directory %MyDirectoryWithoutSlash%
C:\My Directory\ %MyDirectoryWithSlash%
X:\My Directory X:\My Directory
X:\My Directory\ X:\My Directory\
C:\My Directory\Test %MyDirectoryWithSlash%Test
C:\My Directory\Test\ %MyDirectoryWithSlash%Test\
X:\My Directory\Test X:\My Directory\Test
X:\My Directory\Test\ X:\My Directory\Test\
请注意，候选祖先路径总是先用尾部斜杠搜索，然后再不搜索。这意味着在不太可能发生的情况下，存在两个变量路径，它们的区别仅在于尾部斜杠的存在与否，带有尾部斜杠的变量将被匹配。因此，如上所示，C:\My Directory\Test 将变为 %MyDirectoryWithSlash%Test，这看起来有点奇怪。通过反转函数中第一个 foreach 循环的顺序 from...
foreach ($candidatePath in $filePathAncestorOrSelf, $filePathAncestorOrSelf.TrimEnd('\'))
...到...
foreach ($candidatePath in $filePathAncestorOrSelf.TrimEnd('\'), $filePathAncestorOrSelf)
...相关输出更改为...
InputPath OutputPath
--------- ----------
... ...
C:\My Directory\ %MyDirectoryWithoutSlash%\
... ...
C:\My Directory\Test %MyDirectoryWithoutSlash%\Test
C:\My Directory\Test\ %MyDirectoryWithoutSlash%\Test\
... ...
我想编写一个将常规路径转换为包含环境变量的路径的函数：
例如：
C:\Windows\SomePath
转换为：
%Windir%\SomePath
我该怎么做，这可能吗？
这是我想要做的，但问题是，我需要检查字符串 所有可能的变量，有没有更自动的方法？这样就不需要 -replace 运算符
function Format-Path
{
param (
[parameter(Mandatory = $true)]
[string] $FilePath
)
if (![System.String]::IsNullOrEmpty($FilePath))
{
# Strip away quotations and ending backslash
$FilePath = $FilePath.Trim('"')
$FilePath = $FilePath.TrimEnd('\')
}
$FilePath = $FilePath -replace "C:\Windows", "%Windir%"
$FilePath = $FilePath -replace "C:\ProgramFiles", "%ProgramFiles%"
$FilePath = $FilePath -replace "C:\ProgramFiles (x86)", "%ProgramFiles (x86)%"
# ETC.. the list goes on..
return $FilePath
}
# test case
Format-Path '"C:\Windows\SomePath\"'
输出为：
%Windir%\SomePath
编辑：
无效的输入或错误的代码并不是真正的问题，因为最后 $Path 可以很容易地检查：
Test-Path -Path ([System.Environment]::ExpandEnvironmentVariables($FilePath))
这是我最终尝试将其自动化的结果：
function Format-Path {
param (
[string]$path
)
## Environmental variable list
$EV_Variables = ( gci env:* | Where-Object {$_.Name -notin "SystemDrive", "HomeDrive" -and $_.Value -notmatch ";"} | sort-object name )
## Compare string
while ($EV_Variables.Value -like $path) {
foreach ($EC in $EV_Variables) {
if ( $path -like "*$($EC.value)*") {
$path = $path.Replace($EC.Value, "%$($EC.Name)%")
}
}
}
$path
}
Format-Path "C:\Program Files (x86)\Nmap\nmap.exe"
Format-Path "C:\Windows"
Format-Path "C:\Program Files"
Format-Path "C:\Program Files (x86)"
哪个returns:
%nmap%
%SystemRoot%
%ProgramFiles%
%ProgramFiles% (x%NUMBER_OF_PROCESSORS%%PROCESSOR_LEVEL%)
我在一些环境变量上对此进行了测试，它对大多数环境变量都有效，但围绕某些环境变量存在一些问题，例如上面显示的 %NUMBER_OF_PROCESSORS%，但我确定您可以将它们从变量列表中排除。
谢谢大家的建议，我看到 Owain Esau 已经 post 编辑了问题
我也在研究解决方案。
如果我不post我得出的结果可能是个错误:
function Format-Path
{
param (
[parameter(Mandatory = $true)]
[string] $FilePath
)
$SearchString = Split-Path -Path $FilePath -Parent
$Variables = @(Get-ChildItem Env:) | Sort-Object -Descending { $_.Value.length }
foreach ($Value in $Variables.Value)
{
if ($Value -like "*$SearchString")
{
$Replacement = "%" + @(($Variables | Where-Object { $_.Value -eq $Value} ).Name)[0] + "%"
return $FilePath.Replace($SearchString, $Replacement)
}
}
}
Format-Path "C:\Windows\SomePath"
Format-Path "C:\Program Files (x86)\SomePath"
Format-Path "C:\Program Files\SomePath"
Format-Path "C:\ProgramData\SomePath"
# does not work for %SystemDrive%
Format-Path "C:\SomePath"
输出：
%SystemRoot%\SomePath
%ProgramFiles(x86)%\SomePath
%ProgramFiles%\SomePath
%ProgramData%\SomePath
除 %SystemDrive% 需要进一步改进外，此方法有效。
我会留下这个问题以供改进。
下面的代码是我对此的看法。路径和反斜杠操作有一些特殊性，所以我试图在评论中解释所有内容。
有一个关键点，那就是 无限字符串搜索，例如 -replace、-like、.Contains() 等执行的搜索，并且可以当一个变量路径的值是另一个变量路径或目录路径的子字符串时，会产生不良结果。例如，给定 %ProgramFiles% (C:\Program Files) 和 %ProgramFiles(x86)% (C:\Program Files (x86))，路径 C:\Program Files (x86)\Test 可以转换为 %ProgramFiles% (x86)\Test 而不是 %ProgramFiles(x86)%\Test 如果 %ProgramFiles% 刚好在 %ProgramFiles(x86)% 之前测试。
解决方案是只比较一个变量的路径和一个完整的路径段。也就是说，在路径 C:\Program Files (x86)\Test 的情况下，比较会像这样...
- 测试与原始路径是否相等
C:\Program Files (x86)\Test。没有匹配的变量。 - 测试与父路径是否相等
C:\Program Files (x86)。%ProgramFiles(x86)%匹配。没有进一步的祖先路径（即C:）被测试。 %ProgramFiles%永远不会匹配，因为未测试部分路径C:\Program Files。
通过仅针对完整路径段进行测试，变量与候选路径的比较顺序无关紧要。
New-Variable -Name 'VariablesToSubstitute' -Option Constant -Value @(
# Hard-code system variables that contain machine-wide paths
'CommonProgramFiles',
'CommonProgramFiles(x86)',
'ComSpec',
'ProgramData', # Alternatively: ALLUSERSPROFILE
'ProgramFiles',
'ProgramFiles(x86)',
'SystemDrive'
'SystemRoot' # Alternatively: WinDir
'MyDirectoryWithoutSlash' # Defined below
'MyDirectoryWithSlash' # Defined below
);
function Format-Path
{
param (
[parameter(Mandatory = $true)]
[string] $FilePath
)
if (![System.String]::IsNullOrEmpty($FilePath))
{
# Strip away quotations
$FilePath = $FilePath.Trim('"')
# Leave trailing slashes intact so variables with a trailing slash will match
#$FilePath = $FilePath.TrimEnd('\')
}
# Initialize this once, but only after the test code has started
if ($null -eq $script:pathVariables)
{
$script:pathVariables = $VariablesToSubstitute | ForEach-Object -Process {
$path = [Environment]::GetEnvironmentVariable($_)
if ($null -eq $path)
{
Write-Warning -Message "The environment variable ""$_"" is not defined."
}
else
{
return [PSCustomObject] @{
Name = $_
Path = $path
}
}
}
}
# Test against $FilePath and its ancestors until a match is found or the path is empty.
# Only comparing with complete path segments prevents performing partial substitutions
# (e.g. a path starting with %ProgramFiles(x86)% being substituted with %ProgramFiles%,
# or "C:\Windows.old" being transformed to "%SystemRoot%.old")
for ($filePathAncestorOrSelf = $FilePath;
-not [String]::IsNullOrEmpty($filePathAncestorOrSelf);
# Split-Path -Parent removes the trailing backslash on the result *unless* the result
# is a drive root. It'd be easier to normalize all paths without the backslash, but
# Split-Path throws an error if the input path is a drive letter with no slash, so
# normalize everything *with* the backslash and strip it off later.
$filePathAncestorOrSelf = EnsureTrailingBackslash (
# Protect against the case where $FilePath is a drive letter with no backslash
# We have to do this here because we want our initial path above to be
# exactly $FilePath, not (EnsureTrailingBackslash $FilePath).
Split-Path -Path (EnsureTrailingBackslash $filePathAncestorOrSelf) -Parent
)
)
{
# Test against $filePathAncestorOrSelf with and without a trailing backslash
foreach ($candidatePath in $filePathAncestorOrSelf, $filePathAncestorOrSelf.TrimEnd('\'))
{
foreach ($variable in $pathVariables)
{
if ($candidatePath -ieq $variable.Path)
{
$variableBasePath = "%$($variable.Name)%"
# The rest of the path after the variable's path
$pathRelativeToVariable = $FilePath.Substring($variable.Path.Length)
# Join-Path appends a trailing backslash if the child path is empty - we don't want that
if ([String]::IsNullOrEmpty($pathRelativeToVariable))
{
return $variableBasePath
}
# Join-Path will join the base and relative path with a slash,
# which we don't want if the variable path already ends with a slash
elseif ($variable.Path -like '*\')
{
return $variableBasePath + $pathRelativeToVariable
}
else
{
return Join-Path -Path $variableBasePath -ChildPath $pathRelativeToVariable
}
}
}
}
}
return $FilePath
}
function EnsureTrailingBackslash([String] $path)
{
return $(
# Keep an empty path unchanged so the for loop will terminate properly
if ([String]::IsNullOrEmpty($path) -or $path.EndsWith('\')) {
$path
} else {
"$path\"
}
)
}
使用这个测试代码...
$Env:MyDirectoryWithoutSlash = 'C:\My Directory'
$Env:MyDirectoryWithSlash = 'C:\My Directory\'
@'
X:
X:\Windows
X:\Windows\system32
X:\Windows\system32\cmd.exe
X:\Windows.old
X:\Windows.old\system32
X:\Windows.old\system32\cmd.exe
X:\Program Files\Test
X:\Program Files (x86)\Test
X:\Program Files (it's a trap!)\Test
X:\My Directory
X:\My Directory\Test
'@ -split "`r`n?" `
| ForEach-Object -Process {
# Test the path with the system drive letter
$_ -replace 'X:', $Env:SystemDrive
# Test the path with the non-system drive letter
$_
} | ForEach-Object -Process {
$path = $_.TrimEnd('\')
# Test the path without a trailing slash
$path
# If the path is a directory (determined by the
# absence of an extension in the last segment)...
if ([String]::IsNullOrEmpty([System.IO.Path]::GetExtension($path)))
{
# Test the path with a trailing slash
"$path\"
}
} | ForEach-Object -Process {
[PSCustomObject] @{
InputPath = $_
OutputPath = Format-Path $_
}
}
...我得到这个结果...
InputPath OutputPath
--------- ----------
C: %SystemDrive%
C:\ %SystemDrive%\
X: X:
X:\ X:\
C:\Windows %SystemRoot%
C:\Windows\ %SystemRoot%\
X:\Windows X:\Windows
X:\Windows\ X:\Windows\
C:\Windows\system32 %SystemRoot%\system32
C:\Windows\system32\ %SystemRoot%\system32\
X:\Windows\system32 X:\Windows\system32
X:\Windows\system32\ X:\Windows\system32\
C:\Windows\system32\cmd.exe %ComSpec%
X:\Windows\system32\cmd.exe X:\Windows\system32\cmd.exe
C:\Windows.old %SystemDrive%\Windows.old
X:\Windows.old X:\Windows.old
C:\Windows.old\system32 %SystemDrive%\Windows.old\system32
C:\Windows.old\system32\ %SystemDrive%\Windows.old\system32\
X:\Windows.old\system32 X:\Windows.old\system32
X:\Windows.old\system32\ X:\Windows.old\system32\
C:\Windows.old\system32\cmd.exe %SystemDrive%\Windows.old\system32\cmd.exe
X:\Windows.old\system32\cmd.exe X:\Windows.old\system32\cmd.exe
C:\Program Files\Test %ProgramFiles%\Test
C:\Program Files\Test\ %ProgramFiles%\Test\
X:\Program Files\Test X:\Program Files\Test
X:\Program Files\Test\ X:\Program Files\Test\
C:\Program Files (x86)\Test %ProgramFiles(x86)%\Test
C:\Program Files (x86)\Test\ %ProgramFiles(x86)%\Test\
X:\Program Files (x86)\Test X:\Program Files (x86)\Test
X:\Program Files (x86)\Test\ X:\Program Files (x86)\Test\
C:\Program Files (it's a trap!)\Test %SystemDrive%\Program Files (it's a trap!)\Test
C:\Program Files (it's a trap!)\Test\ %SystemDrive%\Program Files (it's a trap!)\Test\
X:\Program Files (it's a trap!)\Test X:\Program Files (it's a trap!)\Test
X:\Program Files (it's a trap!)\Test\ X:\Program Files (it's a trap!)\Test\
C:\My Directory %MyDirectoryWithoutSlash%
C:\My Directory\ %MyDirectoryWithSlash%
X:\My Directory X:\My Directory
X:\My Directory\ X:\My Directory\
C:\My Directory\Test %MyDirectoryWithSlash%Test
C:\My Directory\Test\ %MyDirectoryWithSlash%Test\
X:\My Directory\Test X:\My Directory\Test
X:\My Directory\Test\ X:\My Directory\Test\
请注意，候选祖先路径总是先用尾部斜杠搜索，然后再不搜索。这意味着在不太可能发生的情况下，存在两个变量路径，它们的区别仅在于尾部斜杠的存在与否，带有尾部斜杠的变量将被匹配。因此，如上所示，C:\My Directory\Test 将变为 %MyDirectoryWithSlash%Test，这看起来有点奇怪。通过反转函数中第一个 foreach 循环的顺序 from...
foreach ($candidatePath in $filePathAncestorOrSelf, $filePathAncestorOrSelf.TrimEnd('\'))
...到...
foreach ($candidatePath in $filePathAncestorOrSelf.TrimEnd('\'), $filePathAncestorOrSelf)
...相关输出更改为...
InputPath OutputPath
--------- ----------
... ...
C:\My Directory\ %MyDirectoryWithoutSlash%\
... ...
C:\My Directory\Test %MyDirectoryWithoutSlash%\Test
C:\My Directory\Test\ %MyDirectoryWithoutSlash%\Test\
... ...