Powershell 在 windows 和 unix 中正确生成文件路径 [英] Powershell to generate file paths correctly in windows and unix
问题描述
我想为 powershell 脚本中的文件路径生成一个字符串.我希望它在 windows 和 mac 中都能使用.
I want to generate a string for a file path inside a powershell script. I want this to work in both in windows and mac.
目前代码被硬编码到窗口之类的路径(\" -> windows，/" -> unix):<代码>$templatep="$CoreRoot\templates\$serviceName"
At the moment the code is hardcoded to windows like paths ("\" -> windows, "/" -> unix):
$templatep="$CoreRoot\templates\$serviceName"
我将其更改为:<代码>$templatep= Join-Path $CoreRoot "templates" $serviceName它适用于带有 Powershell 6.0 的 Mac.但是它在我的带有 Powershell 4 的 Windows 服务器中不起作用.我必须做这样的事情:
I changed this to:
$templatep= Join-Path $CoreRoot "templates" $serviceName
And it works in mac with Powershell 6.0. BUT it doesn't work in my windows server with Powershell 4. I have to do something like this:
<代码>$templatep= Join-Path $CoreRoot -ChildPath "templates" |加入路径 -ChildPath $serviceName
知道为什么这仅适用于我的 Mac 吗?这是 powershell 5 或 6 中的新功能吗?我不喜欢必须通过管道连接多个连接路径.有没有更好的方法来做到这一点?
Any idea why this is just working in my mac? Is this a new feature in powershell 5 or 6? I dont't like the having to pipe multiple Join-Paths. Is there a better way to do this?
谢谢！
推荐答案
首先，使用 .NET 框架的解决方法:
First, a workaround using the .NET framework:
[IO.Path]::Combine('a', 'b', 'c')
这在Unix上产生a/b/c，在Windows上产生a\b\c，并且方便地支持任意个路径组件.
This yields a/b/c on Unix, and a\b\c on Windows, and conveniently supports any number of path components.
注意:
此解决方法仅适用于 filesystem 路径，而
Join-Path旨在与任何 PowerShell 驱动器提供程序的路径配合使用.
This workaround is only for filesystem paths, whereas
Join-Pathis designed to work with any PowerShell drive provider's paths.
确保除了 first 之外没有其他组件以 \ (Windows) 或 / (Unix) 开头，因为任何然后忽略前面的组件；例如，在 Windows 上:[IO.Path]::Combine('\a', '\b', 'c') # ->'\b\c' - '\a' 被忽略(!)
请注意，Join-Path不会表现出这种行为；有关详细信息，请参阅我的这个答案.
Make sure that no component other than the first starts with \ (Windows) or / (Unix), because any preceding component is then ignored; e.g., on Windows:
[IO.Path]::Combine('\a', '\b', 'c') # -> '\b\c' - '\a' is ignored(!)
Note that Join-Path does not exhibit this behavior; see this answer of mine for details.
作为使用管道对Join-Path调用进行排序的替代，您可以简单地使用(...)(子表达式):
As an alternative to sequencing Join-Path calls with a pipeline you can simply use (...) (a subexpression):
Join-Path a (Join-Path b c) # -> 'a\b\c' (on Windows)
Join-Path -? 显示的语法自 Windows PowerShell v5.1.14393.693 起(省略附带参数):
The syntax displayed by Join-Path -? as of Windows PowerShell v5.1.14393.693 (incidental parameters omitted):
Join-Path [-Path] <String[]> [-ChildPath] <String> ...
根据这个语法，调用Join-Path a b c应该会导致语法错误，这确实发生了.
Based on this syntax, invocation Join-Path a b c should result in a syntax error, which is indeed what happens.
相比之下，PowerShell [Core] v6+ 中显示的语法揭示了一个附加参数:
By contrast, the syntax displayed in PowerShell [Core] v6+ reveals an additional parameter:
Join-Path [-Path] <String[]> [-ChildPath] <String> [[-AdditionalChildPath] <String[]>]
它是附加的 -AdditionalChildPath 参数，它以收集所有剩余位置参数(ValueFromRemainingArguments)的方式声明，即使指定任意数量的子组件起作用，例如，Join-Path abc 确实起作用.
It is the additional -AdditionalChildPath parameter, which is declared in a manner that collects all remaining positional arguments that (ValueFromRemainingArguments), that makes specifying an arbitrary number of child components work, so that Join-Path a b c indeed works, for instance.
不幸的是，此增强功能不会向后移植到 Windows PowerShell.
Unfortunately, this enhancement won't be back-ported to Windows PowerShell.
注意，即使 [-Path] 是一个 array 参数，它的目的不是接受单个的多个子路径组件输出路径，但允许加入多个父子路径对；例如:
Note that even though [-Path] <String[]> is an array parameter, its purpose is not to accept multiple child path components of a single output path, but to allow joining of multiple parent-child path pairs; e.g.:
$ Join-Path a,b c # same as: Join-Path -Path a,b -ChildPath c
a\c
b\c
最后，即使虽然可能不建议这样做，但您通常可以在两个平台上使用硬编码 / 作为路径分隔符，因为许多 Windows API 函数以及 PowerShell 自己的 cmdlet 接受 \ 和 / 可互换.
但是，并非所有实用程序都可能以这种方式运行，因此使用适合平台的分隔符通常更安全.
Finally, even though it's probably not advisable, you can often get away with hard-coding / as the path separator on both platforms, because many Windows API functions as well as PowerShell's own cmdlets accept \ and / interchangeably.
However, not all utilities may behave this way, so it's generally safer to use the platform-appropriate separator.
例如，以下在 Windows 上运行良好:
For instance, the following works just fine on Windows:
Get-Item c:/windows/system32 # same as: Get-Item c:\windows\system32
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