Review: Windows PowerShell 2.0 Best Practices - Introduction

 

 

A while back I received a review copy of Windows PowerShell 2.0 Best Practices by Ed Wilson (blog | twitter) and the Windows PowerShell Teams at Microsoft. Having finally found the time to sit down and really digest the information within, I thought I’d do a multi-part review of the book.  Ed Wilson has compiled an excellent resource not only to show off what PowerShell 2.0 can do, but also to provide practical examples and several useful tips for best practices not only in using PowerShell, but in writing reusable and efficient code.

This book is broken down into 5 major sections:

• Introduction
• Planning
• Designing
• Testing and Deploying
• Optimizing

I want to give a quick overview of what’s contained in each chapter, though I’m not going to include the code from the book. You may be able to get it from the main page for the book, but ideally I think this book is well worth buying. You get a PDF file of the book and all of the code included in the book as well. If you plan to do a lot of PowerShell scripting, this book is well worth the money.  I will say that this book is not designed to teach PowerShell.  Ed Wilson really does expect that readers have a working knowledge of PowerShell. He builds on that knowledge to show how to write PowerShell scripts with these best practices in mind.

Chapter 1 contains an overview of PowerShell 2.0. Ed explains some of the differences between PowerShell 1.0 and 2.0, focusing on the new remoting capabilities, WMI enhancements, changes to the way some cmdlets work, and why they have changed the original behavior. He touches on some of the differences between VBScript and PowerShell and why PowerShell might be a better choice than VBScript, despite people’s familiarity with the latter. One of the key advantages of PowerShell over VBScript is that PowerShell was designed to be run from a prompt or as a script. VBScript must be run through something that calls the script.  This command-line interaction allows people to work with the script in a much more interactive way and even use native Windows commands with which people are already familiar.  Ed closes the chapter by reminding readers of the minimum requirements for PowerShell 2.0, informing readers from where they may obtain the latest version of PowerShell and suggesting where PowerShell 2.0 should be installed (pretty much everywhere).

Chapter 2 is where readers become more familiar with PowerShell 2.0 capabilities. We’ve already read about the promise of PowerShell 2.0, but now we can start to see it in action. Ed starts by introducing readers to the PowerShell 2.0 interactive command line. The first command shows users running processes inside the PowerShell environment.  Ed then shows some of the easiest cmdlets to run and remember, followed by the “most important” cmdlets: Get-Help, Get-Command, and Get-Member.  I agree that these three cmdlets are key. You can always find out more about what commands are available, how to run them, and what properties are available.  Ed then lists several useful cmdlets to enhance filtering, grouping, sorting, and such.  Chapter 2 ends with a good introduction to WMI, Remoting, Services, and the Event Log from a PowerShell perspective.

Chapter 3 concentrates on Active Directory. Ed reminds us that what we typically call “AD” is really a legacy term now and is actually “Active Directory Service Interfaces” or ADSI. We tend to think of AD in terms of users and domains, but it contains much more now than it used to. Ed jumps right in by showing readers how to reference ADSI Users, Groups, and Computers with some quick examples of how to reference each within PowerShell.  There’s then a quick “Inside Track” by James Turner showing how PowerShell can be used to automate some common administrative tasks around user accounts. James tells us to use the right tool for the job as well. While the LDAP functionality allows more authentication methods, the WinNT functionality allows more object types and more familiar syntax.  The bulk of Chapter 3 really concentrates on building a functional script to create and update Users within ADSI. The reader is guided from the more simple scripts to query data through reading a file to automate the creation and updating of user accounts. We also get to see several ways to accomplish this task to introduce the reader to reading from a connection to Excel.

Chapter 4 builds on what we’ve already learned from Chapter 3 to work within ADSI.  Ed starts by helping us become familiar with the AD schema through PowerShell. As always, Ed actually puts to use the “Best Practices” that he wants his readers to learn. His first script includes a full Help example and several functions, followed by a breakdown of each function. I found it helpful to look through the original script while Ed explains the details so I could keep track of how each function fit into the bigger picture.

Ed then demonstrates how to query AD for information, going beyond merely listing the results – this is PowerShell after all and the results can be full objects. He gives a pretty good list of ADSI-related properties, shows how to display results that list results, then moves on to true queries – ADO and OLEDB queries. Of course, his overall goal is to really use PowerShell effectively. ADO and OLEDB are useful, but we also want to be efficient. Therefore, the reader is introduced to the DirectorySearcher class and PowerShell 2.0’s [ADSISearcher] to simplify calling DirectorySearcher. Along the way, we see the “FindOne()” method to limit the results to a single row. That is useful to see what data we can expect.  Some familiarity with ADSI can really help when going through these chapters.

We’re led from these queries to actually managing user accounts. First, the reader needs to understand ADSI User Account Control values. He then shows using the Bitwise AND operation to compare the various bits set and determine properties of the various user accounts. Ed shows how to find and display disabled user accounts in a short script using bitwise AND and color coding. Readers are then shown how to move objects within AD without too much code. The final example details how to find missing values within AD. These are the values that are expected, but not always completed.  Once again, I found it very useful to see the whole script while Ed explains each step of the script.  Be sure to include the backtick if you want to type these scripts yourself and try them.

 

Conclusion

The Introductory section of Windows PowerShell 2.0 Best Practices is well-written and serves its purpose of getting the readers ready to move through the rest of the book. If I have any complaints about this section it’s that it uses ADSI pretty heavily. For people who don’t work directly with ADSI on a regular basis, a lot of the examples are harder to follow. While still possible to see the best practices for PowerShell, it’s easy to get lost in trying to figure out what Ed is doing with ADSI.  The Planning section in chapters 5-8 seem to be less focused on a specific set of functionality and much more on how to plan and use PowerShell effectively.  I plan to post a review of those chapters in the near future.

 

I’d appreciate feedback on this review. Too lengthy? Too short? Let me know what’s good and what’s not good. I’d like to write a useful and honest review for those considering this book.