Convert long file names to short names windows 10?

Is there a way to convert long file names into a truncated short form on pc? Is there a simple way to do this? I'm new to using the command prompt / PowerShell and don't fully understand what long scripts are doing and how to modify them.

I want to transfer all of my files to an external hard drive but many of the files are from a mac with long names and I receive an error when I try to transfer them.

Answer

Save the following into a file Set-DosFileName.ps1

[CmdletBinding(SupportsShouldProcess=$true)]
Param(
    [parameter(Mandatory=$true)]
    [string]$folder,
    [switch]$recurse
)
$fso = New-Object -ComObject Scripting.FileSystemObject
Get-ChildItem -Path $folder -File -Recurse:$recurse | ForEach-Object {
    $shortName = $fso.getfile($_.Fullname).ShortName
    if ($shortName -ne $_.Name)
    {
        $fullShortName = Join-Path $_.Directory -ChildPath $shortName
        Move-Item -LiteralPath $_.Fullname -Destination $fullShortName
    }
}

To use this open a PowerShell window and change into the directory where you saved the file:

cd "D:\folder where you saved the script"

then:

.\Set-DosFileName.ps1 -folder "D:\myfiles\Foo Bar" -whatif

The script should show how it would rename your files.

To include all files in subdirectories add the -recurse switch:

.\Set-DosFileName.ps1 -folder "D:\myfiles\Foo Bar" -whatif -recurse

If everything looks fine, remove the -whatif switch to actually rename the files. I would still keep a backup of the original files just in case anything goes wrong.

I haven't tested this with a large number of files, be aware that some file names may be pretty ugly.