Batch renaming files by PowerShell?

Question

How can I rename files in a folder that have random names and random extensions to a sequence like the example below: 0001.pdf 0002.pdf ..... 0100.png and continue.

And if possible then generate a .txt file with the names and extensions generated.

For the .txt file if not possible Powershel could be another application.

Searching I got the code below, but I can't fix it for the task I need.

Dir | Rename-Item –NewName { $_.name –replace " - ","0" }

Answer 1

Wrap the call to Rename-Item in ForEach-Object then maintain a counter in a variable:

$fileNumber = 1
Get-ChildItem path\to\folder\containing\random\files -File |ForEach-Object {
    # Construct new file name
    $newName = '{0:0000}{1}' -f $fileNumber,$_.Extension

    # Perform rename
    $_ |Rename-Item -NewName $newName

    # Increment number
    $fileNumber++
}