Apply powershell to subfolders

January 7, 2025

I have a lot of folders with image files that accidentally saved without extension.
I’ve managed to work out how to add the extension:

ls -file | ? {$_.extension -eq ''} | % {ren $_ ($_.name + '.jpeg')}

… but I can’t work out how to make it apply to all subfolders.
This command doesn’t work:

Get-ChildItem -Recurse ls -file | ? {$_.extension -eq ''} | % {ren $_ ($_.name + '.jpeg')}

any ideas where I’m going wrong, please?

>Solution :

First, make sure to remove ls from Get-ChildItem -Recurse ls -file – ls is an alias for Get-ChildItem, and since you’ve already specified the cmdlet name PowerShell will attempt to locate a folder named ls and start the search from there.

Second, instead of passing $_ to Rename-Item (alias ren) as a positional argument, pipe it:

Get-ChildItem -Recurse -File | ? {$_.extension -eq ''} | Rename-Item -NewName { $_.Name + '.jpeg' }

Piping the whole file info object to Rename-Item allows PowerShell to bind the correct absolute path to the file system object, and it’ll thus start working for files in nested folders.