Powershell function returns double path when appending subdir

Question

I have a curious problem. I have a function that takes a $srcDir and $destDir and $topDir $srcDir is in the format of \$topDir\subDir1\subDir2\subDir..n What I need is to append all subDir parts to the $destDir

My approach so far is to split-path until I reach $topDir and then append the resulting string to $destDir using join-path.

If no sub directories are appended to $destPath then the return is perfect.

If I append a path to $destPath then the return is $destPath $destPath

Here is the output in sample values

• srcIn: C:\path\topdir\
• destIn: \\server\path\
• destOut: \\server\path\

Now if I have subdirectories

• scrIn: C:\path\topdir\subpath\subpath1
• destIn: \server\path\
• destOut: \\server\path\subpath\subpath1 \\server\path\subpath\subpath1

Inside the function the path looks correct. There is no dbl of the destOut value. once I return from the function it has the double value.

How do I prevent this? I just wanted a simple function to obtain the sub directories and append to the destDir so I can preserve folder structure and move files to their appropriate directories.

Ty.

function GetSubDir
{
    param(
        [Parameter(Mandatory=$true)]
        [string]$filePath, 
        [Parameter(Mandatory=$true)]
        [string]$destDir,
        [string]$topDir="Disk1"
    )


    $tmpPath = Split-Path $filePath -parent
    $fileName = Split-Path $filePath -leaf 
    $tmp= Split-Path $filePath -leaf
    while ($tmp -ne $topDir)
    {

        if (test-path $tmpPath -PathType container)
        {
            if ($subDir){$subDir = "$tmp\$subDir"}
            else {$subDir = "$tmp\"}
        }
        else {$subDir = "$tmp"}
        $tmp = Split-Path $tmpPath -leaf
        $tmpPath = Split-Path $tmpPath -parent

    }

    $destPath = Join-Path $destDir $subDir
    if (!(Test-Path $destPath)) {md $destPath}
    if (Test-Path $destPath -PathType container) 

    #name is set in calling function
    {$destPath = Join-Path $destPath $name}

    return $destPath
}

Answer 1

With a tip of the hat to @TessellatingHecker, let me agree that one line will suffice, but I believe it is this one line that is needed:

$srcPath -replace [Regex]::Escape($topDir), $destDir

Now let's encapsulate that in a function...

function MapSubDir($srcPath, $topDir, $destDir)
{
    $srcPath -replace [Regex]::Escape($topDir), $destDir
}

And feed it your original two test cases to observe you get your desired results:

PS> $srcPath= "C:\path\topdir\"
PS> $topDir= "C:\path\topdir\"
PS> $destDir= "\\server\path\"
PS> MapSubDir $srcPath $topDir $destDir
\\server\path

PS> $srcPath = "C:\path\topdir\subpath\subpath1"
PS> MapSubDir $srcPath $topDir $destDir
\\server\path\subpath\subpath1

Answer 2

The md function (alias for new-item) returns the directory it creates. Since you don't do anything with that value, it is added to the output stream of the function.

To fix this, do one of these:

md $destPath | out-null

[null]md $destPath