Rename or Remove Characters From a Filename with PowerShell - windows

Question

I am trying to rename or remove part of a filename. I have a scheduled job that moves an updated file from one server to another. Once the file is moved it need to be renamed. For example: Filename_01-23-AB.exe to Filename.exe I want to remove everything from the "_" to the "." and leave the extension intact. I found the following code that should do this but I can't seem to get it to work. Am I headed down the right path here?
## Removes the build number from the filename of "Filename_XX-XX-XX.exe" leaving the new filename to be "Filename.exe" ##
$File = -Path "C:\Temp\TestPath\"
foreach ($File in gci *.exe) {
$Fname = ($File.name).split('.')[0] ## item before the '.' ##
$Prefix = $Fname.split('_')[0] ## item before the '_' ##
$Newname = $Prefix + '.exe'
Rename-Item $file $Newname
}

Answer 1

I've tried simplifying what you're tying to do:
pushd "C:\Temp\TestPath\"
dir | ? { $_.Name -like "*.exe" } |
% { Rename-Item $_ "$($_.BaseName.split('_')[0])$($_.Extension)" }
popd
First, this changes the directory your PowerShell is looking at to your defined directory (pushd).
Then it will get the contents of your directory, find all objects with the extension of .exe, and split the file's base name at the underscore. popd will then set the directory back to where-ever it was previous to running this script.

Answer 2

I think this can be simplifyed even more using a regex to remove everything between the first underscore and the file extension:
$Path= 'C:\Temp\TestPath\'
Get-ChildItem $Path -Filter "*_*.exe" | foreach {
$_ | Rename-Item -NewName ($_.Name -replace '(?=_).+(?=\.)')
}
This also works when the filename doesn't contain an underscore.
And here the regex demo.

Answer 3

!not tested
try this
$path = 'C:\Temp\TestPath\'
gci $path *.exe | ? basename -match '_' | % {
# if the file.txt already exists, rename it to file-1.txt and so on
$num = 1
$base = $_.basename.substring(0, $_.basename.indexof('_'))
$ext = $_.extension
$dir = $_.directory
$newname = Join-Path $dir "$base$ext"
while (Test-Path $newname) {
$newname = Join-Path $dir "$base-$num$ext"
$num++
}
# finally, rename the file
ren $_.fullname $newname
}