Scripts often need to dynamically find out what directory they are executed from.  In CMD scripts this is done by %~dp0.  For powershell the following will do the trick.

  split-path -parent $MyInvocation.MyCommand.Definition

 When this is run anywhere in the script body (not a function within the script) it will return the directory currently holding the running script.  If you execution this from a function within a script though, it will print out the body of the function.  If you need to know the directory of the script inside the body of the script, store it in script level variable.

  $script:mypath = $MyInvocation.MyCommand.Definition

  function printScriptPath() { return $script:mypath; }