Rename files to lowercase in Powershell - 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() }
}
}

Answer 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.

Answer 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()}

Answer 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)";}

Answer 4

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

Answer 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
}

Answer 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() }

Answer 7

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() }

Answer 8

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