PowerShell Split File

function Split-File
{
  <# 
      .SYNOPSIS 
      Splits a file into multiple parts 
 
      .DESCRIPTION 
      Splits a file into smaller parts. The maximum size of the part files can be specified. The number of parts required is calculated. 
 
      .EXAMPLE 
      Split-File -Path 'c:\test.zip' -PartSizeBytes 2.5MB 
      Splits the file c:\test.zip in as many parts as necessary. Each part file is no larger than 2.5MB 
 
      .EXAMPLE 
      Split-File -Path 'c:\test.zip' -PartSizeBytes 2.5MB -AddSelfExtractor 
      Splits the file c:\test.zip in as many parts as necessary. Each part file is no larger than 2.5MB 
      Adds a powershell script that joins the parts when run, and adds a shortcut file to 
      run the PowerShell extractor script on double-click, essentially adding a self-extractor 
  #>


    
    param
    (
        # Path to the file you want to split
        [Parameter(Mandatory,HelpMessage='Path to the file you want to split')]
        [String]
        $Path,

        # maximum size of file chunks (in bytes)
        [int]
        $PartSizeBytes = 1MB,

        # when specified, add a an extractor script and link file to easily convert
        # chunks back into the original file
        [Switch]
        $AddSelfExtractor
    )

    try
    {
        # get the path parts to construct the individual part
        # file names:
        $fullBaseName = [IO.Path]::GetFileName($Path)
        $baseName = [IO.Path]::GetFileNameWithoutExtension($Path)
        $parentFolder = [IO.Path]::GetDirectoryName($Path)
        $extension = [IO.Path]::GetExtension($Path)

        # get the original file size and calculate the
        # number of required parts:
        $originalFile = New-Object -TypeName System.IO.FileInfo -ArgumentList ($Path)
        $totalChunks = [int]($originalFile.Length / $PartSizeBytes) + 1
        $digitCount = [int][Math]::Log10($totalChunks) + 1

        # read the original file and split into chunks:
        $reader = [IO.File]::OpenRead($Path)
        $count = 0
        $buffer = New-Object -TypeName Byte[] -ArgumentList $PartSizeBytes
        $moreData = $true

        # read chunks until there is no more data
        while($moreData)
        {
            # read a chunk
            $bytesRead = $reader.Read($buffer, 0, $buffer.Length)
            # create the filename for the chunk file
            $chunkFileName = "$parentFolder\$fullBaseName.{0:D$digitCount}.part" -f $count
            Write-Verbose -Message "saving to $chunkFileName..."
            $output = $buffer

            # did we read less than the expected bytes?
            if ($bytesRead -ne $buffer.Length)
            {
                # yes, so there is no more data
                $moreData = $false
                # shrink the output array to the number of bytes
                # actually read:
                $output = New-Object -TypeName Byte[] -ArgumentList $bytesRead
                [Array]::Copy($buffer, $output, $bytesRead)
            }
            # save the read bytes in a new part file
            [IO.File]::WriteAllBytes($chunkFileName, $output)
            # increment the part counter
            ++$count
        }
        # done, close reader
        $reader.Close()

        # add self-extractor
        if ($AddSelfExtractor)
        {
            Write-Verbose -Message "Adding extractor scripts..."
            
            # define the self-extractor powershell script:
            $extractorName = "${fullBaseName}.{0:D$digitCount}.part.ps1" -f $count
            $extractorPath = Join-Path -Path $parentFolder -ChildPath $extractorName
            $filePath = '$PSScriptRoot\' + "$baseName$extension"

            # define the self-extractor shortcut file that launches
            # the powershell script on double-click:
            $linkName = "Extract ${fullBaseName}.lnk"
            $linkPath = Join-Path -Path $parentFolder -ChildPath $linkName

            # this will be used inside the extractor script to find the
            # part files via relative path:
            $currentFile = '"$PSCommandPath"'
            $currentFolder = '"$PSScriptRoot"'
            
            # write the extractor script source code to file:
            " 
                # copy the join-file source code into the extractor script: 
                function Join-File { 
                ${function:Join-File} 
                } 
                # join the part files and delete the part files after joining: 
                Join-File -Path ""$filePath"" -Verbose -DeletePartFiles 
 
                # remove both extractor scripts: 
                (Join-Path -Path $currentFolder -ChildPath '$linkName') | Remove-Item 
                Remove-Item -Path $currentFile 
 
                # open the extracted file in windows explorer 
                explorer.exe ""/select,""""$filepath"""""" 
            " | Set-Content -Path $extractorPath

            # create a shortcut file that launches the extractor script
            # when it is double-clicked:
            $shell = New-Object -ComObject WScript.Shell
            $scut = $shell.CreateShortcut($linkPath)
            $scut.TargetPath = "powershell.exe"
            $scut.Arguments = "-nop -executionpolicy bypass -file ""$extractorPath"""
            $scut.WorkingDirectory = ""
            $scut.IconLocation = "$env:windir\system32\shell32.dll,162"
            $scut.Save()
        }
    }
    catch
    {
        throw "Unable to split file ${Path}: $_"
    }
}