What's the best way to determine the location of the current PowerShell script?

Question

Whenever I need to reference a common module or script, I like to use paths relative to the current script file. That way, my script can always find other scripts in the library.

So, what is the best, standard way of determining the directory of the current script? Currently, I'm doing:

$MyDir = [System.IO.Path]::GetDirectoryName($myInvocation.MyCommand.Definition) 

I know in modules (.psm1) you can use $PSScriptRoot to get this information, but that doesn't get set in regular scripts (i.e. .ps1 files).

What's the canonical way to get the current PowerShell script file's location?

Answer 1

PowerShell 3+

# This is an automatic variable set to the current file's/module's directory $PSScriptRoot 

PowerShell 2

Prior to PowerShell 3, there was not a better way than querying the MyInvocation.MyCommand.Definition property for general scripts. I had the following line at the top of essentially every PowerShell script I had:

$scriptPath = split-path -parent $MyInvocation.MyCommand.Definition