script to convert all .txt file content to lowercase - windows

Question

I have about 700 .txt files scattered in 300 directories and sub-directories.
I would like to open each of them, convert all text inside to lowercase, including Unicode characters (such as É to é), then save and close them.
Can you advise how it could be done through PowerShell? It is my own computer and I have admin rights.
I have started with the below:
Get-ChildItem C:\tmp -Recurse -File | ForEach-Object {}
but I am not sure what to put between the brackets of ForEach-Object {}.

Answer 1

Simple script, with your requirements:
$path=".\test\*.txt"
#With Default system encoding
Get-ChildItem $path -Recurse | foreach{
(Get-Content $_.FullName).ToLower() | Out-File $_.FullName
}
#Or with specified encoding
Get-ChildItem $path -Recurse | foreach{
(Get-Content $_.FullName -Encoding Unicode).ToLower() |
Out-File $_.FullName -Encoding Unicode
}
#Test
Get-ChildItem $path -Recurse | foreach{
Write-Host "`n File ($_.FullName): `n" -ForegroundColor DarkGreen
Get-Content $_.FullName
}

Answer 2

You need to use :
# Reading the file content and converting it to lowercase and finally putting the content back to the file with the same filename.
(Get-Content C:\path\file.txt -Raw).ToLower() | Out-File C:\path\file.txt -Force
inside the foreach and then change the case to lower.
If you want to iterate all the files in the corresponding folder then you can use another foreach to get that job done.
Hope it helps.