Dot sourcing a PowerShell script.

PowerShell works in scopes. At the very top layer, you have a global scope. When you run a script, it is ran in a script scope inside the global. If you run any functions inside that script, they run in their own function scope inside the script scope, which is inside the global scope.

When the function is finished and it exits its scope, all the data in the function is lost. When the script ends, all of its data and the knowledge of the existence of the scripts functions are also lost. What if you wanted to keep the functions from the script available to the shell? That is where dot sourcing comes into play.

Let’s take a look at this simple function:

Function Display-Info
{
Write-Host (Get-WmiObject Win32_OperatingSystem).Caption
}

Display-Info

The output of this function, which changes depending on the client it is ran on, is:

Microsoft Windows 7 Ultimate

I know, this is a very simple function. the problem is, after the execution is completed, I cannot use the function again in the shell. To help solve this, I’m going to save this function as Library.ps1. You can name it anything that you want. I’m creating Library.ps1 to hold all the functions that I create and want to use in the shell or to make them available to my other PowerShell scripts.

I’m going to run this program in my shell environment.

I’m now going to attempt to execute the function directly from my shell.

No luck.

When I execute the command Dir Function: I can see that my function, Display-Info, is not listed.

I’m going to next dot source my library.ps1 script into the shell so that I can use its functions from within the shell and all scripts that I run in that shell session.

To do this, I execute the command . ./library.ps1. Just so we are clear, the command is: Period – Space – Period – forward slash – library.ps1.

Now when I execute Dir Function: I can see my function is listed.

I can now also execute it directly in the shell.

Just remember that once you close the shell, you will need to dot source your PowerShell script back in. The dot sourcing puts the functions in the global scope. When you close the global scope, you lose everything in it.

Comments

Sticky Key problem between Windows Server 2012 and LogMeIn

This week I instructed my first class using Windows Server 2012 accessed via LogMeIn and discovered a Sticky Key problem every time you press the Shift key. Here is my solution to resolve this. First off, in the Preferences of LogMeIn for the connection to the Windows Server, click General . Change the Keyboard and mouse priority to Host side user and click Apply at the bottom. On the Windows 2012 server, open the Control Panel – Ease of Access – Change how your keyboard works . Uncheck Turn on Sticky Keys . Click Set up Sticky Keys . Uncheck Turn on Sticky Keys when SHIFT is pressed five times . Click OK twice. If you are using Windows Server 2012 as a Hyper-V host, you will need to redo the Easy of Use settings on each guest operating system in order to avoid the Sticky Key Problem. Updated Information: March 20, 2013 If you continue to have problems, Uncheck Turn on Filter Keys .

Where did a User’s Account Get Locked Out?

Updated: May 15, 2015 When this article was originally published, two extra carriage returns were add causing the code to malfunction. The code below is correct. My client for this week’s PowerShell class had a really interesting question. They needed to know where an account is being locked out at. OK, interesting. Apparently users hop around clients and forget to log off, leading to eventual lock out of their accounts. The accounts can be unlocked, but are then relocked after Active Directory replication. This problem is solved in two parts. The first one is to modify the event auditing on the network. The second part is resolved with PowerShell. The first part involves creating a group policy that will encompass your Domain Controllers. In this GPO, make these changes. Expand Computer Configuration \ Policies \ Windows Settings \ Security Settings \ Advanced Audit Policy Configuration \ Audit Policies \ Account Management Double click User Account Management C...

Backup and Restore AD LDS with DSDBUTIL.exe

Active Directory Lightweight Directory Services allow you to create a directory service that allows applications to have access to user accounts, groups, and authentication similar to Active Directory Domain Services. The big advantage here is that the schema of the directory service will not be bound by the rules of an Active Directory database. Exchange 2007/2010, for example, use an instance of AD LDS on the Edge Transport Server to provide for user authentication from the internet. Because your Active Directory database is not exposed to the internet, this is more secure. Applications will handle most of the dirty work should they require AD LDS. You may want to make sure the database is being backed up and also have a restore plan in place. Should the database become corrupt, the application that uses that database will fail. This document will walk you through backing up and restoring an instance of AD LDS using the dsdbutil.exe command. Fi...

Jason Yoder, MCT

Search This Blog