Powershell function which opens the containing folder of a given file

open-containingfolder.ps1

# Powershell function which opens the containing folder of a given file
# in the default program (this will be Windows Explorer 99% of the time).
# 
# Note that if -File is actually a folder, it will open that folder's
# parent folder.
#
# Usage:
#   Open-ContainingFolder $env:AppData
#   Open-ContainingFolder .\somefile.txt
#   Open-ContainingFolder C:\Windows\System32\ping.exe

function Open-ContainingFolder {
    Param(
        [Parameter(Mandatory=$true)]
        [string]$File
    )
    if (Test-Path -LiteralPath $File) {
        Invoke-Item $(Split-Path -Parent $File)
    } else {
        $host.ui.WriteErrorLine("$File does not exist")
    }