How to remove first word from folder name? - powershell

Question

I have 26 folders with the names of my students (Firstname Lastname_somedata). Windows sorts this with their first name. I want to automate the deletion of their first name so their last last name comes first and sorts like it should.
Thanks!
Edit: An Example folder name "Anna Ansaleere_28032_assignsubmission_file_".
I have been trying some stuff but nothing that actually produced something usefull.

Answer 1

As commented, it would be better to have the first- and lastnames swapped with a comma in between. That way the possibility of ending up with duplicate folder names is rather unlikely.
I'd suggest something like this:
$rootFolder = 'D:\Test'
Get-ChildItem -Path $rootFolder -Directory | ForEach-Object {
$student, $remainder = $_.Name -split '_', 2
# in case there is a folder where no space is found between the First and Last name
if (!($student.Contains(' '))) {
Write-Host "Not possible to find the First and Lastname in $($_.FullName)"
continue
}
$firstname, $lastname = $student -split ' ', 2
$newName = '{0}, {1}_{2}' -f $lastname, $firstname, $remainder
$_ | Rename-Item -NewName $newName -WhatIf
}
If you are satisfied with the resuts shown in the PowerShell console, remove the -WhatIf switch so the folders are actually renamed.
Before:
Anna Ansaleere_28032_assignsubmission_file
Henry This-Or-That_98765_assignsubmission_file
John Doe_12345_rejection_file
After:
Ansaleere, Anna_28032_assignsubmission_file_
Doe, John_12345_rejection_file
This-Or-That, Henry_98765_assignsubmission_file
P.S. if your version of PowerShell is less than 3.0, do Get-ChildItem -Path $rootFolder | Where-Object { $_.PSIsContainer } | ForEach-Object {..} to return directories only

Answer 2

With the assumption that "somedata" do not contain a space (studentID parhaps?) this would work.
$folder_path = "C:\Users\USER\Documents\stackoverflow"
#Gets all folders from $folder_path location.
$folders = Get-ChildItem $folder_path | where {$_.PSIsContainer -eq $true}
foreach ($folder in $folders)
{
#Takes the second string after spliting it on "space" character.
#In case of: Jonas Olsson_1452385
#The second string would be: Olsson_1452385
$new_name = ($folder.name).split(" ")[1]
$new_name
#Rename folder to new name
Rename-Item $folder.FullName -NewName $new_name
}
PS, next time, let us know what you have tried when you post.