运行带有变量 -Path 参数的 Powershell 命令

Question

Can someone please explain the following behaviour to me?

PS C:\Users\Kenny> $filePath = "C:\\Complicated.File.Path.That.Has.Special-Chars`[but-no.spaces`]and.definitely.exists\"
PS C:\Users\Kenny> cd $filePath
cd : Cannot find path 'C:\\Complicated.File.Path.That.Has.Special-Chars[but-no.spaces]and.definitely.exists\' because it does not exist.
At line:1 char:1
+ cd $filePath
+ ~~~~~~~~~~~~~~~~                                 
    + CategoryInfo          : ObjectNotFound: (C:\\Complicated...initely.exists\:String) [Set-Location], ItemNotFoundE
   xception
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.SetLocationCommand

PS C:\Users\Kenny> cd 'C:\\Complicated.File.Path.That.Has.Special-Chars`[but-no.spaces`]and.definitely.exists\'
PS C:\Complicated.File.Path.That.Has.Special-Chars[but-no.spaces]and.definitely.exists> cd c:
PS C:\Users\Kenny> Write-Host $filePath
C:\\Complicated.File.Path.That.Has.Special-Chars[but-no.spaces]and.definitely.exists\
PS C:\Users\Kenny> cd "$filePath"
cd : Cannot find path 'C:\\Complicated.File.Path.That.Has.Special-Chars[but-no.spaces]and.definitely.exists\' because it does not exist.
At line:1 char:1
+ cd "$filePath"
+ ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (C:\\Complicated...initely.exists\:String) [Set-Location], ItemNotFoundE
   xception
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.SetLocationCommand

PS C:\Users\Kenny> cd ${filePath}
cd : Cannot find path 'C:\\Complicated.File.Path.That.Has.Special-Chars[but-no.spaces]and.definitely.exists\' because it does not exist.
At line:1 char:1
+ cd ${originalPath}
+ ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (C:\\Complicated...initely.exists\:String) [Set-Location], ItemNotFoundE
   xception
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.SetLocationCommand

PS C:\Users\Kenny> cd ${$filePath}
cd : Cannot process argument because the value of argument "path" is null. Change the value of argument "path" to a
non-null value.
At line:1 char:1
+ cd ${$filePath}
+ ~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Set-Location], PSArgumentNullException
    + FullyQualifiedErrorId : ArgumentNull,Microsoft.PowerShell.Commands.SetLocationCommand

PS C:\Users\Kenny> cd $($filePath)
cd : Cannot find path 'C:\\Complicated.File.Path.That.Has.Special-Chars[but-no.spaces]and.definitely.exists\' because it does not exist.
At line:1 char:1
+ cd $($filePath)
+ ~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (C:\\Complicated...initely.exists\:String) [Set-Location], ItemNotFoundE
   xception
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.SetLocationCommand

If I had a penny for every minute I've wasted on PowerShell's insistance that backticks, quotes and other meta-characters are just right , I would be the richest man on Earth! Somebody please save me from this madness!

And BTW, what I'm actually trying to do is recurse through a bunch of folders and delete everything that isn't a video file, like so...

Remove-Item -Path $filePath -Recurse -Exclude '*.avi','*.mkv','*.mp4'

...which doesn't work for (presumably) the same reason: not being able to pass a variable to the -Path parameter. And if someone is feeling really generous, they could also help me with this . MTIA: :D

Answer 1

Use -LiteralPath instead of -Path because some of the special characters where interpreted with -Path .

Remove-Item -LiteralPath

Answer 2

Special characters are just so much fun in PS right?

-LiteralPath works exactly like Patrick explained, but they don't allow for wildcards; because they're literal.

Have you tried using single quotes ' instead of double quotes ". This allows you to escape special characters, while still evaluating wildcards. Try the commands below:

New-Item -Path 'C:\Users\username\PSScripts\bracket`[\te$t.txt'
Get-Item -Path  'C:\Users\username\PSScripts\bracket`[\*'

Also, if it helps, I use VSCode for most scripting and, if you use tab completion, it will format this properly for you.

I hope that helps!

Answer 3

The solution to my overall problem ended up being this line of my batch script:

powershell -Command "Get-ChildItem -Recurse -LiteralPath %filePath% | Where-Object Extension -match '^(?!(\.avi|\.mkv|\.mp4)$)' | Remove-Item"

The regex was the hardest to get right, since I haven't used negative lookaheads before, but after ~2 hours of total time spent on this one line of code , it finally works!