如何获得的实际大小，在磁盘上的PowerShell中的文件？ [英] How to get the actual size-on-disk of a file from PowerShell?

问题描述

我写一个管理脚本，我需要计算磁盘上的文件的大小。

I am writing an administrative script, and I need to calculate the size of files on disk.

这些文件是在一个COM pressed NTFS卷。

These files are on a compressed NTFS volume.

我不能使用 FileInfo.Length ，因为这是文件的大小，而不是大小在磁盘上。举例来说，如果我有一个100MB的文件，但它仅使用25MB由于NTFS COM pression，我需要我的脚本返回25MB。

I can't use FileInfo.Length, because that is file size and not size on disk. For example, if I have a 100MB file, but it is only using 25MB due to NTFS compression, I need my script to return 25MB.

有没有办法做到这一点在PowerShell中？

Is there a way to do this in Powershell?

（我了解 GetCom pressedFileSize（） Win32调用，但我希望这已经wrappered在一定程度上。）

(I know about the GetCompressedFileSize() Win32 call, but I was hoping that this is already wrappered at some level.)

推荐答案

（编辑）

我想通了，如何动态的属性（称为脚本属性）添加到文件对象，所以现在，我可以使用语法：$ theFileObject.Com pressedSize读取尺寸

I figured out how to dynamically add a property (called a "script property") to the Fileobject, so now, I can use the syntax: $theFileObject.CompressedSize to read the size.

（编辑完）

阅读Goyuix的反应，我觉得很酷，但不存在某种在PowerShell中类型的扩展能力？。所以，后来我发现这个在Scott Hanselman帖子：的http://www.hanselman.com/blog/MakingJunctionsReparsePointsVisibleInPowerShell.aspx

Read Goyuix's response, and I thought "Cool, but isn't there some kind of type-extension capability in Powershell?". So then I found this Scott Hanselman post: http://www.hanselman.com/blog/MakingJunctionsReparsePointsVisibleInPowerShell.aspx

和我创建了一个脚本属性的FileInfo对象：.com的pressedSize

And I created a Script Property for the FileInfo object: CompressedSize.

下面是我所做的：（注：我是很新的PowerShell的，或者至少我不使用它太多这也许可以做出好了很多，但这里是我所做的：

Here's what I did: (note: I'm quite new to Powershell, or at least I don't use it much. This could probably be made a lot better, but here's what I did:

首先，我从Goyuix的编译后的Ntfs.ExtendedFileInfo。我把DLL在我的PowerShell配置文件目录（文件\ WindowsPowershell）

First, I compiled the Ntfs.ExtendedFileInfo from Goyuix's post. I put the DLL in my Powershell profile directory (Documents\WindowsPowershell)

接下来，我创建了我的个人资料目录中的文件名为My.Types.ps1xml。

Next, I created a file in my profile directory named My.Types.ps1xml.

我把下面的XML到文件：

I put the following XML into the file:

<Types>
<Type>
    <Name>System.IO.FileInfo</Name>
    <Members>
        <ScriptProperty>
          <Name>CompressedSize</Name>
          <GetScriptBlock>
            [Ntfs.ExtendedFileInfo]::GetCompressedFileSize($this.FullName)
          </GetScriptBlock>
        </ScriptProperty>
    </Members>
</Type>
</Types>

这code（合并后入式系统），将一个名为com pressedSize属性动态添加到通过GET-childitem / DIR返回FileInfo的对象。但是PowerShell不会了解code着呢，不知道我的DLL呢。我们处理，在下一步的：

That code (once merged into the type system) will dynamically add a property named CompressedSize to the FileInfo objects that are returned by get-childitem/dir. But Powershell doesn't know about the code yet, and it doesn't know about my DLL yet. We handle that in the next step:

编辑Profile.ps1。在同一目录下。现在，我的档案文件恰好已经在它的一些东西，因为我有社区扩展了PowerShell的安装。但愿，我包括你需要在接下来的code段，这样它会工作，即使一台机器，不具有扩展的一切。添加以下code到Profile.ps1：

Edit Profile.ps1. in the same directory. Now, my Profile file happens to already have some stuff in it because I have the Community Extensions for powershell installed. Hopefully, I'm including everything that you need in this next code snippet, so that it will work even on a machine that does not have the extensions. Add the following code to Profile.ps1:

#This will load the ExtendedfileInfo assembly to enable the GetCompressedFileSize method.  this method is used by the
#PSCompressedSize Script Property attached to the FileInfo object.
$null = [System.Reflection.Assembly]::LoadFile("$ProfileDir\ntfs.extendedfileinfo.dll") 

#merge in my extended types
$profileTypes = $ProfileDir | join-path -childpath "My.Types.ps1xml"
Update-TypeData $profileTypes

现在，我引用了$ ProfileDir变量之前定义在我Profile.ps1脚本。万一它不是你的，这里的定义是：

Now, the $ProfileDir variable that I reference is defined earlier in my Profile.ps1 script. Just in case it's not in yours, here is the definition:

$ProfileDir = split-path $MyInvocation.MyCommand.Path -Parent

就是这样。接下来，您运行PowerShell的时候，你可以访问FileInfo对象上的COM pressedSize财产就好像它是任何其他财产。 例如：

That's it. The next time that you run Powershell, you can access the CompressedSize property on the FileInfo object just as though it is any other property. Example:

$ MYFILE = DIR C：\ TEMP \ myfile.txt的

$myFile = dir c:\temp\myfile.txt

$ myFile.Com pressedSize

$myFile.CompressedSize

这工作（在我的机器上，反正），但我很乐意听到它是否适合在与最佳实践。有一件事我知道我做错了：在Profile.ps1文件，我返回的LoadFile的结果转化成我不会用（$空=等等等等）的变量。我这样做是为了晚饭preSS加载文件到控制台的结果的显示。有可能是一个更好的办法来做到这一点。

This works (on my machine, anyway), but I would love to hear whether it fits in with best practices. One thing I know I'm doing wrong: in the Profile.ps1 file, I return the results of LoadFile into a variable that I'm not going to use ($null = blah blah). I did that to suppress the display of result of load file to the console. There is probably a better way to do it.

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