Native PowerShell wrapper for MKLINK.

mklink.psm1

function New-Symlink {
    <#
    .SYNOPSIS
        Creates a symbolic link.
    #>
    param (
        [Parameter(Position=0, Mandatory=$true)]
        [string] $Link,
        [Parameter(Position=1, Mandatory=$true)]
        [string] $Target
    )

    Invoke-MKLINK -Link $Link -Target $Target -Symlink
}


function New-Hardlink {
    <#
    .SYNOPSIS
        Creates a hard link.
    #>
    param (
        [Parameter(Position=0, Mandatory=$true)]
        [string] $Link,
        [Parameter(Position=1, Mandatory=$true)]
        [string] $Target
    )

    Invoke-MKLINK -Link $Link -Target $Target -HardLink
}


function New-Junction {
    <#
    .SYNOPSIS
        Creates a directory junction.
    #>
    param (
        [Parameter(Position=0, Mandatory=$true)]
        [string] $Link,
        [Parameter(Position=1, Mandatory=$true)]
        [string] $Target
    )

    Invoke-MKLINK -Link $Link -Target $Target -Junction
}


function Invoke-MKLINK {
    <#
    .SYNOPSIS
        Creates a symbolic link, hard link, or directory junction.
    #>
    [CmdletBinding(DefaultParameterSetName = "Symlink")]
    param (
        [Parameter(Position=0, Mandatory=$true)]
        [string] $Link,
        [Parameter(Position=1, Mandatory=$true)]
        [string] $Target,

        [Parameter(ParameterSetName = "Symlink")]
        [switch] $Symlink = $true,
        [Parameter(ParameterSetName = "HardLink")]
        [switch] $HardLink,
        [Parameter(ParameterSetName = "Junction")]
        [switch] $Junction
    )

    # Ensure target exists.
    if (-not(Test-Path $Target)) {
        throw "Target does not exist.`nTarget: $Target"
    }

    # Ensure link does not exist.
    if (Test-Path $Link) {
        throw "A file or directory already exists at the link path.`nLink: $Link"
    }

    $isDirectory = (Get-Item $Target).PSIsContainer
    $mklinkArg = ""

    if ($Symlink -and $isDirectory) {
        $mkLinkArg = "/D"
    }

    if ($Junction) {
        # Ensure we are linking a directory. (Junctions don't work for files.)
        if (-not($isDirectory)) {
            throw "The target is a file. Junctions cannot be created for files.`nTarget: $Target"
        }

        $mklinkArg = "/J"
    }

    if ($HardLink) {
        # Ensure we are linking a file. (Hard links don't work for directories.)
        if ($isDirectory) {
            throw "The target is a directory. Hard links cannot be created for directories.`nTarget: $Target"
        }

        $mkLinkArg = "/H"
    }

    # Capture the MKLINK output so we can return it properly.
    # Includes a redirect of STDERR to STDOUT so we can capture it as well.
    $output = cmd /c mklink $mkLinkArg `"$Link`" `"$Target`" 2>&1

    if ($lastExitCode -ne 0) {
        throw "MKLINK failed. Exit code: $lastExitCode`n$output"
    }
    else {
        Write-Output $output
    }
}

Export-ModuleMember New-Symlink, New-Hardlink, New-Junction