How to normalize a path in PowerShell?

Question

I have two paths:

fred\\frog

and

..\\frag

I can join them together in PowerShell like this:

Answer 1

This library is good: NDepend.Helpers.FileDirectoryPath.

EDIT: This is what I came up with:

[Reflection.Assembly]::LoadFrom("path\to\NDepend.Helpers.FileDirectoryPath.dll") | out-null

Function NormalizePath ($path)
{
    if (-not $path.StartsWith('.\'))  # FilePathRelative requires relative paths to begin with '.'
    {
        $path = ".\$path"
    }

    if ($path -eq '.\.')  # FilePathRelative can't deal with this case
    {
        $result = '.'
    }
    else
    {
        $relPath = New-Object NDepend.Helpers.FileDirectoryPath.FilePathRelative($path)
        $result = $relPath.Path
    }

    if ($result.StartsWith('.\')) # remove '.\'. 
    {
        $result = $result.SubString(2)
    }

    $result
}

Call it like this:

> NormalizePath "fred\frog\..\frag"
fred\frag

Note that this snippet requires the path to the DLL. There is a trick you can use to find the folder containing the currently executing script, but in my case I had an environment variable I could use, so I just used that.