Rename files to lowercase in Powershell

Question

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() }
    }
}

In PowerShell 7 at least, `Rename-Item` doesn't error out if the new name is the same as the old name. I'm not sure which version this behavior changed in though. But your first attempt piping `gci` to `rename-item` works now. — codewario, Apr 23 '21 at 18:29

score 35 · Accepted Answer · answered Sep 29 '10 at 16:13

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.

Worth mentioning that this works for renaming files but not directories. For directories, you'll need to do 2 rename operations. See [here](https://til.secretgeek.net/powershell/Rename_to_lower_case.html) for an example. — velsietis, Jan 29 '20 at 15:40

score 20 · Answer 2 · answered Sep 29 '10 at 16:51

20

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()}

answered Sep 29 '10 at 16:51

Keith Hill

194,368
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Thanks. And to change file names we can use this : gci . -recurse -force | ?{!$_.PSIsContainer} | rni -New {$_.Name.replace("aaa","bbb")} – Mahmoud Moravej May 11 '13 at 12:36

score 3 · Answer 3 · answered Jun 19 '18 at 09:38

3

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)";}

answered Jun 19 '18 at 09:38

omni

4,104
8
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I used this to rename a few million files - one catch is it doesn't handle files with a bracket eg: '[' or ']' . I think something [here](https://superuser.com/questions/212808/powershell-bug-in-copy-move-rename-when-filename-contains-square-bracket-charac) has a solution. I didn't attempt to fix because I have a post work around and this took care of most issues. – Logan Waggoner Apr 13 '23 at 01:39
You might also need the folders lower cased - something like this can be run from the root of where you are working: ``` #Get the directories / sub directories and rename to lowercase Get-ChildItem -recurse| ?{ $_.PSIsContainer -And $_.Name -CMatch "[A-Z]" } | %{ $NName = $_.Name.ToLower() #Set temporary name to enable rename to the same name; Windows is not case sensitive $TempItem = Rename-Item -Path $_.FullName -NewName "x$NName" -PassThru Rename-Item -Path $TempItem.FullName -NewName $NName } ``` – Logan Waggoner Apr 13 '23 at 02:46
Should use Rename-Item -LiteralPath instead of -Path as some file types are not supported (like brackets otherwise). – Logan Waggoner Apr 17 '23 at 00:47

score 2 · Answer 4 · answered Oct 15 '13 at 14:41

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

score 2 · Answer 5 · answered Sep 07 '16 at 16:43

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
   }

score 0 · Answer 6 · answered Oct 11 '10 at 01:49

0

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() }

answered Oct 11 '10 at 01:49

Jay Bazuzi

45,157
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JensGC · Answer 7 · 2020-02-19T16:24:18.560

0

A small but important correction to the answer from Jay Bazuzi. The -cne (case sensitive not equal) operator must be used if the where-part should return anything.

Additionally I found that the Path parameter needed to be present. This version worked in my setup:

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

edited Feb 19 '20 at 16:24

answered Feb 19 '20 at 15:41

JensGC

1
2

score 0 · Answer 8 · answered Jan 03 '22 at 20:53

for everyone who is following this thread; the following line can also be used to lower both files and directories.

Get-ChildItem -r  | Rename-Item -NewName { $_.Name.ToLower().Insert(0,'_') } -PassThru |  Rename-Item -NewName { $_.Name.Substring(1) }

Main post: https://stackoverflow.com/a/70559621/4165074

score 0 · Answer 9 · answered May 17 '23 at 23:48

Modified to work with [] brackets in the name or other unsupported chars and will handle the directories too (or you can leave that out). I pieced this together from various places.

Should be able to put this in a file, then navigate to the target dir and run it from there.

#Get the directories / sub directories and rename to lowercase 
Get-ChildItem -recurse| ?{ $_.PSIsContainer -And $_.Name -CMatch "[A-Z]" } | %{ 
$NName = $_.Name.ToLower() 
#Set temporary name to enable rename to the same name; Windows is not case sensitive 
$TempItem = Rename-Item -LiteralPath $_.FullName -NewName "x$NName" -PassThru Rename-Item -LiteralPath $TempItem.FullName -NewName $NName }

#Now handle all the files
Get-ChildItem -LiteralPath . -Recurse | Where{ $_.Name -cne $_.Name.ToLower() } | ForEach-Object { 
$tn="$($_.Name)-temp"; $tfn="$($_.FullName)-temp"; 
$nn=$_.Name.ToLower(); 
Rename-Item -LiteralPath $_.FullName -NewName $tn; 
Rename-Item -LiteralPath $tfn -NewName $nn -Force; 
Write-Host "New Name: $($nn)";
}

Rename files to lowercase in Powershell

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