Rename files to lowercase in Powershell

问题

I am trying to rename a bunch of files recursively using Powershell 2.0. The directory structure looks like this:

Leaflets
+ HTML
  - File1
  - File2
  ...
+ HTMLICONS
  + IMAGES
    - Image1
    - Image2
  - File1
  - File2
  ...
+ RTF
  - File1
  - File2
  ...
+ SGML
  - File1
  - File2
  ...

I am using the following command:

get-childitem Leaflets -recurse | rename -newname { $_.name.ToLower() }

and it seems to rename the files, but complains about the subdirectories:

Rename-Item : Source and destination path must be different.

I reload the data monthly using robocopy, but the directories do not change, so I can rename them by hand. Is there any way to get get-children to skip the subdirectories (like find Leaflets -type f ...)?

Thanks.

UPDATE: It appears that the problem is with files that are already all lower case. I tried changing the command to:

get-childitem Leaflets -recurse | if ($_.name -ne $_name.ToLower()) rename -newname { $_.name.ToLower() }

but now Powershell complains that if is not a cmdlet, function, etc. Can I pipe the output of get-childitem to an if statement?

UPDATE 2: This works:

$files=get-childitem Leaflets -recurse
foreach ($file in $files)
{
    if ($file.name -ne $file.name.ToLower())
    {
        rename -newname { $_.name.ToLower() }
    }
}

回答1:

Even though you have already posted your own answer, here is a variation:

dir Leaflets -r | % { if ($_.Name -cne $_.Name.ToLower()) { ren $_.FullName $_.Name.ToLower() } }

Some points:

• dir is an alias for Get-ChildItem (and -r is short for -Recurse).
• % is an alias for ForEach-Object.
• -cne is a case-sensitive comparison. -ne ignores case differences.
• $_ is how you reference the current item in the ForEach-Object loop.
• ren is an alias for Rename-Item.
• FullName is probably preferred as it ensures you will be touching the right file.

If you wanted to excludes directories from being renamed, you could include something like:

if ((! $_.IsPsContainer) -and $_.Name -cne $_.Name.ToLower()) { ... }

Hopefully this is helpful in continuing to learn and explore PowerShell.

回答2:

Keep in mind that you can pipe directly to Rename-Item and use Scriptblocks with the -NewName parameter (because it also accepts pipeline input) to simplify this task:

Get-ChildItem -r | Where {!$_.PSIsContainer} | 
                   Rename-Item -NewName {$_.FullName.ToLower()}

and with aliases:

gci -r | ?{!$_.PSIsContainer} | rni -New {$_.FullName.ToLower()}

回答3:

slight tweak on this, if you only want to update the names of files of a particular type try this:

get-childitem *.jpg | foreach { if ($_.Name -cne $_.Name.ToLower()) { ren $_.FullName $_.Name.ToLower() } }

this will only lowercase the jpg files within your folder and ignore the rest

回答4:

There are many issues with the previous given answers due to the nature of how Rename-Item, Piping, Looping and the Windows Filesystem works. Unfortunatly the the most simple (not using aliases for readability here) solution I found to rename all files and folders inside of a given folder to lower-case is this one:

Get-ChildItem -Path "/Path/To/You/Folder" -Recurse | Where{ $_.Name -cne $_.Name.ToLower() } | ForEach-Object { $tn="$($_.Name)-temp"; $tfn="$($_.FullName)-temp"; $nn=$_.Name.ToLower(); Rename-Item -Path $_.FullName -NewName $tn; Rename-Item -Path $tfn -NewName $nn -Force; Write-Host "New Name: $($nn)";}

回答5:

You need to temporarily rename them to something else then name them back all lower case.

$items = get-childitem -Directory -Recurse

foreach ($item in $items)
{

   if ($item.name -eq $item.name.ToLower())
   {    

       $temp = $item.FullName.ToLower() + "_"
       $name = $item.FullName.ToLower()
       ren $name $temp

       ren $temp $name
   }

回答6:

It's more idomatic in PowerShell to use where instead of if in a pipeline:

gci -Recurse Leaflets | 
    ? { $_.Name -ne $_.Name.ToLower()) } | 
    % { ren -NewName $_.Name.ToLower() }

来源：https://stackoverflow.com/questions/3822745/rename-files-to-lowercase-in-powershell