Powershell: processing files in two folders based on what's in them

I have two directories: c:\Rar and c:\unRared

Rar - contains hundreds of RA开发者_C百科R'ed files. Only one file inside the RAR. File inside the archive is with *.TRN extension. UnRared has unarchived files (hundreds of files with *.TRN extension)

I've been trying to create a Powershell script to extract only files that have not been extracted already.

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can't you just supply parameters to whatever compression program you have telling it not to overwrite existing files?

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Knocked this out on my own...well, not really, with the help of developer

$dir1='C:\temp\aaa'
$dir2='C:\temp\bbb'
$CmdPath = "C:\Program Files (x86)\WinRAR\RAR.exe"
$Files2Extract = get-childitem -path 'C:\temp\aaa' -recurse -name -filter *.rar
#$d2 = get-childitem -path $dir2 -recurse

foreach($file in $Files2Extract){
    $justname =  $dir2+'\\'+(split-path $file -leaf).split(".")[0]+'.trn'

    if(!(Test-Path -path $justname)) {
        &$CmdPath e $file $dir2
    }

}