PowerShell: Put Number in a Filename in Front of the Filename

I had to work with some files where the interesting number in the filename is not at the start, but after a keyword. So, if I wanted to sort the files in the folder by the interesting number, I’d need to rename the files to put the number at the start. Might seem like a pointless endeavour but I have my reasons.

In the image below is a quick and simple example of how the tool works. I’m interested in the number after CJ, so the keyword to split on is CJ (not a word but you get it), and there are 2 digits we’re interested in. After renaming, I can sort the files in the folder using the special number.

Image: Example of FileNameSorter.ps1

The Script

I named it FileNameSorter.ps1 but you can call it anything you like. Then I ran as .\FileNameSorter.ps1.

Function Wr{

  If(!$Args[0]){Write-Host}

  elseif(!$Args[1]){Write-Host $Args[0] -NoNewLine}

  else{Write-Host $Args[0] -NoNewLine -ForegroundColor $Args[1]}

}

Wr "Put Number in a Filename in front of the Filename" CYAN;Wr

Wr "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" CYAN;Wr

[System.Object]$Pwd = Pwd

[String]$Current = $Pwd.path

Wr "Current Folder: " CYAN; Wr $Current WHITE;Wr

Wr "Target Folder (or press ENTER to use current): " YELLOW

[String]$Target = Read-Host

If(!$Target){$Target = $Current}

elseif(!(Test-Path $Target)){Wr "$Target is not a valid path!" RED;EXIT}

[System.Array]$Files = (Get-ChildItem -Path $Target).Name

Wr "Files in target:" CYAN;Wr

$Files | Foreach{ Wr $_ WHITE;Wr }

Wr "Keyword to Split on: " YELLOW

[String]$KeyWord = Read-Host

Wr "How many digits in the number: " YELLOW

[Int16]$Digits = Read-Host

Function FNS-Rename-Files{

  Param([Switch]$Rename)

  $Files | Foreach{

    [System.Array]$S = ($_ -Split $KeyWord)

    If($S.count -gt 1){

      $NosAfterKeyword = ($S[1] -replace '\D+(\d+)','$1')

      If($NosAfterKeyword.length -ge $Digits){

        $Nos = $NosAfterKeyword.Substring(0,$Digits)

        If(!$_.StartsWith($Nos) -and [Bool]($Nos -as [double])){

          If($Rename){Rename-Item ($Target + "\" + $_) ($Nos + "_" + $_)}

          $_ = ($Nos + "_" + $_) 

        }

      }

    }

    Wr $_ WHITE;Wr

  }

}

Wr "Will rename files to:" CYAN;Wr

FNS-Rename-Files

Wr "Okay to proceed (Y/N)? " YELLOW

[String]$YesOrNo = Read-Host

If($YesOrNo -ne "Y"){EXIT}

Wr "Files renamed to:" CYAN;Wr

FNS-Rename-Files -Rename